Main Lib- LIBRARY OF THE UNIVERSITY OF CALIFORNIA. GIFT OF Class ^JJL^T ''-frjifll ** TY OF CALIFORNIA-COLLEGE OF AGRICULTURE.! AGRICULTURAL EXPERIMENT STATION. E. W. HILGARD, Director. BERKELEY, CAL. KESISTANT VINES- SELECTION, ADAPTATION, AND GRAFTING. BY ARTHUR P. HAYNE, Pn.B., Assistant in Charge of Viticulture and Olive Culture. APPENDIX TO VITICULTURAL REPORT, 1896. SACRAMENTO; A. j. JOHNSTON, : : : : : SUPERINTENDENT STATE PRINTING, 1897. Viticulture, Agricultural Experiment Station, University of California. Principal Topics . Resistant Vines. Qfp.-fc vo^u^: . Jt&ft ?^r 1897 Vine Pruning. Btl. 119 1897 Death of Vines in Santa Clara 134 1901 Herbaceous Grafting. M 146 1902 Resistant Vines arid Hybrids. M 148 1902 Vine Diseases in Sonoma w 168 1905 Selection of Vine Cuttings Circ. 26 1906 Grafting Resistant Vines. Bui. 180 1906 Oidiura of the Vine. 186 1907 Insects of the Vine. M 192 1907 Best Wine Grapes M 193 1907 Pruning Young Vines . M H H Pruning Sultaninas " M Grape Root Worm 196 1908 Resistant Vines. M 197 1908 Vine Diseases. ff " " Grape Leaf Hopper M 198 M Grape Growing in Imperial. 210 1911 Cif ( n c I ) B ^ ^ 3 rt9$i i * &3X& .- \C m lr J I . i. n i oi i aO '*lb " '^4' x/a^ *- ^ i . aaaiv Lib. Dept ' jsniort oH -rti ^^ -J^t? 3 ,0-riO a^:^i/ft % yO :wiV lo iiy . f jt.fff ao/iiV ^dui^Bi'a'dfl i- 11 * 19 cf o H UNIVERSITY OF CALIFORNIA-COLLEGE OF AGRICULTURE. AGRICULTURAL EXPERIMENT STATION. E. W. HILGARD, Director. BERKELEY, CAL. EESISTANT VINES- SELECTION, ADAPTATION, AND GRAFTING. BY ARTHUR P. HAYNE, Pn.B., Assistant in Charge of Viticulture and Olive Culture. APPENDIX TO VITICULTURAL REPORT, 1896. SACRAMENTO; A. j. JOHNSTON, : : : : : SUPERINTENDENT STATE PRINTING. 1897. HE UNIVERSITY OF EXPERIMENT STATION AND SUB-STATIONS OF THE UNIVERSITY OF CALIFORNIA-1895-96. CENTRAL STATION (Berkeley, Alameda County). E. W. HILGARD, Ph.D., LL.D. (Professor of Agriculture), Director and Chemist. E. J. WICKSON, M. A. (Associate Professor of Agriculture, Horticulture, and Entomology), Superintendent of Agricultural Grounds. R. H. LOUGHRIDGE, Ph.D. (Assistant Professor), Agricultural Geologist and Agricultural Chemist. C. W. WOODWORTH, M.S. (Assistant Professor), Entomologist. W. A. SETCHELL, Ph.D. (Professor of Botany), Botanist. M. E. JAFFA, Pb.B., M. S. (Assistant Professor of Agriculture), First Assistant Chemist in Agricultural Laboratory. ARTHUR P. HAYNE, Ph.B. (Instructor), Assistant in charge of Viticulture and Olive Culture. GEO. E. COLBY, Ph.B. (Instructor), Second Assistant Chemist in Viticultural Laboratory. C. H. SHINN, A.B., Inspector of Stations. F. T. BIOLETTI, B.S. (Instructor), Bacteriologist ; in charge of Viticultural Cellar. EMIL KELLNER, Foreman of Station Grounds. A. V. STUBENRAUCH, Clerk to the Director. SIERRA FOOTHILL CULTURE SUB-STATION (near Jackson, Amador County). R. C. RUST, Patron ; Jackson. -, Foreman ; Jackson. SOUTHERN COAST RANGE CULTURE SUB-STATION (near Paso de Robles, San Luis Obispo County). F. D. FROST, Patron ; Paso Robles. T. F. SEDGWICK, in charge ; Paso Robles. SAN JOAQUIN VALLEY CULTURE SUB-STATION (near Tulare City, Tulare County). JOHN TUOHY, Patron ; Tulare City. JULIUS FORRER, Foreman ; Tulare City. SOUTHERN CALIFORNIA CULTURE SUB-STATION (near Pomona, Los Angeles County). C. F. LOOP, Patron ; Chino. J. W. MILLS, Foreman ; Pomona. CHICO FORESTRY SUB-STATION (near Chico, Butte County). R. F. PENNELL, Patron ; Chico. A. B. BOLAND, Foreman ; Chico. SANTA MONICA FORESTRY SUB-STATION (near Santa Monica, Los Angeles Co.). ROY JONES, Patron ; Santa Monica. J.H. BARBER, Foreman ; Santa Monica. VITICULTURAL SUB-STATION (under private auspices). EAST SIDE SANTA CLARA VALLEY STATION ; Mission San Jos, Alameda County. John Gallegos, Patron ; Mission San Jose". 208859 TABLE OF CONTENTS. PAGE. INTRODUCTORY NOTE 8 PHYLLOXERA: Natural habitat; Evolution of, and resistant vines; Introduc- tion into Europe 9 REMEDIES FOR THE PHYLLOXERA _ 10 Insecticide: Extinction treatment 10 Submersion: Nature of the soil; Depth and duration ; Dangers _. 11 Plantations in Sand 12 Resistant Vines: Replanting of European vines; Influence on growth and crop ; Influence on quality of wine ; Extra expense ; Discovery of the resist- ance of American vines ; First attempts at planting ; Species and varieties ; Vitis Riparia and Rupestris ; Selection ; Cause of failure ; Hybrids and direct producers; Standard of resistance _ _ 12-22 Character of Lands for Resistant Vines : Calcareous soil ; Compactness ; Humid- ity; Fertility; Preparation of the ground; Deep culture _._ 24 QUARANTINE AND DISINFECTION 25 DESCRIPTION OF RESISTANT VINES V. Rupestris; V. Riparia; Lenoir; Herbemont; Solonis; V. Doaniana; V. Calif ornica; V. Arizonica 26 GRAFTING Systems of English ; Cleft ; Ligatures ; Time for grafting ; Cutting off of roots ; Care of grafting vines ; Choice and preservation of scions 37 Grafting on cuttings ; Heeling in ^ 49 NURSERIES Choice and preparation of soils ; Planting ; Care of ; Transplanting. 50-54 ILLUSTRATIONS. Photograph of non-selected and selected vines of the same age, growing side by side in the vineyard of John Swett, Martinez, Cal. Fig. 1. Showing the formation of callus on a scion cut for a cleft-graft. 2. Stock and scion ready for a whip-graft, for grafting of cuttings on small vines. 3. Manner of cutting scion. 4. Respective positions of parallel cuts in scion and stock of cleft-graft. 5, 6. Ordinary cleft-graft on old vine. 7. The scion cut for a cleft-graft. 8. Manner of using rafna on a cutting whip-graft. 9. Manner of using raffia when lead strips are used. 10. Nursery of grafted cuttings, showing method of planting and banking. 11. A six-year-old vine, badly grafted, perishing from phylloxera on roots from scion- 12. Old grafted vine, showing almost normal difference between size of stock and scion. INTRODUCTORY NOTE. Owing to the fact that the vineyards of a part of the State are being destroyed by the phylloxera, and that at any moment the hitherto unaffected parts may become infected, it has been deemed advisable to publish the following bulletin in order to aid those who are already making earnest endeavors to replant their ravaged vineyards, as well as to endeavor to correct misconceptions of some fundamental principles. In this work I have followed very closely my answers to letters of inquiry from the vineyardists who have written to the University for information, so that the bulletin may be considered as an answer to actual questions asked by the vine-growers. I have drawn largely on notes made from the lectures of my former instructor, Professor Pierre Viala, of PEcole Nationale d' Agriculture de Montpellier, France, as well as from the revision of those lectures as given in his valuable book "Adaptation." All those who read French are strongly advised to consult this work, as it is complete scientifically as well as practically. ARTHUR P. HAYNE. December, 1896. RESISTANT VINES; THEIR SELECTION, ADAPTATION, AND GRAFTING. Natural Habitat of the Phylloxera. The phylloxera is a minute insect that is found on both the leaves and roots of the grapevine. It causes, ultimately, the death of all the varieties of the Vitis Vinifera, or European vine, as well as that of many other species. It is essentially an insect of American origin, its native habitat being that part of the United States east of the Rocky Mountains, below the Canada line; it has existed on the American vines in that part of the United States, so far as is known, for ages. Up to a quite recent date, however, little was known of this insect, beyond a few facts concerning the leaf-inhabiting form (sometimes also called the gall form), which, being comparatively harmless in its effects on the vine, was merely noted as a curiosity. Though having lived on the American wild vines of the East for a longer time than history can record, nothing was known concerning its deadly effects upon the non- American species. Evolution of Phylloxera and Resistant Vines. It would seem, from geological specimens of extinct species of American vines, that, for a long time, there has been a sort of struggle going on between the phylloxera and the wild vines. All weakling vines in the forests perished from the bite of the insect, while those that were strong and vigorous did not, but, in conformity with a general law of Nature, gradually developed characteristics or qualities that enabled them to withstand the attacks of the phylloxera. Of course this took a very long time to come about, for such changes in the nature of species do not take place in a few years; science shows that it requires ages to bring about such results. Hence, it is the veriest nonsense to speak of "the root form of the phylloxera having suddenly come into existence since the use of insecticides on the leaves, being forced by the poisoning of its natural habitat to seek shelter and food on the roots." While it is perfectly true that the original insect was probably a leaf insect, just as the oak phylloxera is to-day, yet it took many ages to develop or evolve the root-inhabiting form from it. Introduction into Europe. Probably it would have been many years before the complicated life-history of the phylloxera would have been known, had it not been for the fact that by some unfortunate accident the insect was carried beyond the Atlantic and dropped among the vineyards of the Old World. This occurred some thirty-odd years ago. Finding a new species of grapevine especially well adapted for its growth and development, it began to multiply faster than it did on the wild vines of its native forests, and soon caused the entire destruction of some of the finest vineyards of the Old World. For some time the 10 UNIVERSITY OF CALIFORNIA. cause of the death of the vines was not suspected; but by an accident the roots of the sickly vines were found to be covered with a small in- sect, which was proved to be identical with the Phylloxera Vastatrix of America. At once the search for an economical, effective remedy began. Thousands of plans were proposed and tried by private persons and Gov- ernment commissions; and though many were found that would result in the death of the insect, yet either because of economical reasons, or the danger to the vine arising from the quantities of the insecticide, none were very generally adopted for the saving of the vineyards. REMEDIES. After a quarter of a century of careful and systematic study and experiment, it has been found possible to combat the phylloxera by means of : (a) Insecticides, (b) Submersion, (c) Planting in Sand, (d) Re- sistant Vines. INSECTICIDES. The only two insecticides that have proved at all practical are Carbon Bisulphid and Sulfocarbonate of Potassium. These are either injected into the soil around the vine, killing the insect by the vapor, or they are carried into the soil dissolved in water, as is the case with the sulfocar- bonate; in some cases the carbon bisulphid is mixed by " injectors " with the water and carried into the soil. It is perfectly true that when these insecticides are properly applied under favorable conditions, the phylloxera will be almost entirely exterminated. It is also a fact, how- ever, that owing to the light doses that have to be applied on account of the danger to the roots of the vine, these treatments with insecticides must be given annually. This heavy annual expense, then, makes insecti- cides economically practicable only on the most valuable vineyards, such as those that produce the finest " chateau " wines. Extinction Treatment. In California, with the present state of the market, insecticides are entirely too expensive to be thought of as a permanent thing, though they may be useful in cases where it is desired to kill every living thing, insect or vegetable, in a small spot of a vine- yard that has just been infected. By promptly tearing out the diseased vines as soon as a few become infected, the spread of the phylloxera may be checked for a long time. This treatment "by extinction" has been very successful in checking the rapidity of the spread of the phylloxera in several countries where it has been systematically used. The most striking examples are found in Switzerland. It is now being rigorously applied in the Champagne region of France, and though no hope is entertained of being able to preserve the vineyards for all time, yet it is certain that their ultimate destruction will be delayed very many years. It is a grave mistake to allow the phylloxera to remain undisturbed till it has destroyed the entire vineyard. A great many years may be added to the productiveness of an infected vineyard, if the diseased vines be torn out as soon as they show the effects of the insect. This tearing- out of the sick vines should be done, even if the soil be not treated with insecticides. If nothing else be done, the vines should be carefully RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 11 rooted out and burned on the spot, the ground around being covered lightly with straw or brush, which is immediately burned, so as to destroy all insects that may be on or near the surface of the soil, or on the roots and trunks of the vines. Aside from this use of insecticides for pur- poses of the eradication of the insect from a small spot, it is far too expensive an operation to be relied on in this State, with any known insecticide. While none have thus far been found that are economical, it is by no means certain that the time will not come when we may have a cheap and effective insecticide for our phylloxera-infected vineyards. But the public is warned against trusting to seductive advertisements of those who claim to have infallible remedies. The field has been so carefully worked by the best chemists, entomologists, and practical vineyardists of the world, that there is little probability of anything effective being dis- covered very soon. But even though a very cheap insecticide be found, it must not be forgotten that this must be applied annually, and no matter how slight the expense, this annual treatment merely means a diminished net revenue. Perhaps one of the commonest deceptions practiced by the sellers of phylloxera remedies is the use of powerful fertilizers mixed with some so-called insecticide. By this means it is certain that the vine may be temporarily revived, but the revival is too short-lived to be depended on for crops enough to pay for the treatment, which amounts simply to a heavy fertilization. SUBMERSION. Much misconception has arisen concerning the utility of this opera- tion. While it is perfectly true that, under certain special conditions, it is effective and economical, yet the conditions under which submer- sion is possible are so special that but few can avail themselves of this means of combating the phylloxera. Nature of the Soil. In the first place, the vineyard must be perfectly or almost level, and in easy communication with an abundant water- supply. Then, the soil must be neither too porous nor too compact. Again, the submersion must be continuous, and not interrupted, even for an hour. Should the surface of the soil be exposed for an hour at the end of forty days in a vineyard that requires a sixty-day sub- mersion, the forty days of submersion do not count, but the whole operation has to be begun as though there had never been a day of submersion. We give below a table illustrating some of the special conditions that have to be fulfilled in order to make this seemingly simple operation possible and practically effective. This is dwelt upon somewhat at length, as the Station is in receipt of numerous inquiries on this subject from those who imagine that mere heavy irrigation will be effective in checking the phylloxera. Depth and Duration. In all cases where the loss of water per day, either on account of the permeability of the soil or the evaporation, or both, amounts to more than 500 cubic yards per day on an acre, submersion becomes impossible. 12 UNIVERSITY OP CALIFORNIA. Time Required to kill Phylloxera in a vineyard by Submersion in Water. Duration of submersion. Loss per Acre of Water in 24 Days in Autumn. Days in Winter. Hours. Very slightly permeable soils Medium permeable soils 50 to 55 55 to 60 55 to 60 60 to 65 40 cu. yds. 40 to 120 cu. yds. Permeable soils .. 65 to 70 70 to 75 120 to 280 cu. yds. Very permeable soils 90 90 390 to 450 cu. yds. From the table it will be seen that, with the necessity of Continuous submersion from 1 to 2 feet, the operation is not so simple as many sup- pose. It will not do to leave too much of the trunk of the vine or canes exposed above the water-level. Hence it is that in the case of high- pruned vines the depth of the water must be greater than in the case of short-pruned vines. The duration of the submersion depends, to a certain extent, upon the climate. In very cold countries the duration of the complete submersion may be considerably shortened. The table is given for warm or temperate climates, such as that of California. Dangers of Submersion. It is to be remarked that submerged vines speedily perish from " black knot." "gouty swellings," etc.; besides such vines are extremely sensitive to the attacks of the "powdery mildew" and other fungous diseases. It may be added that heavier fertilization is required on vineyards that are submerged than otherwise would be the case. PLANTING IN SAND. In this case, too, it is to be noted that a merely "sandy soil," as is generally understood by the term in this State, is not sufficient to check the spread or development of the phylloxera. There must be at least 85% of pure sand in a soil that is to be relied on as a phylloxera- proof soil. But even this high percentage of sand is not sufficient, if there be a slight admixture of clay. More or less lime does not make much difference. It has been found that while the Vitis Vinifera will grow well in sandy soils of the above description, yet they require heavy fertilization and yield crops of an inferior quality, though heavy quantity. RESISTANT VINES. It being, then, not economical, except in very special cases, to attempt to destroy the phylloxera itself, we are inevitably driven to the con- clusion that all of our vineyards on non-resistant roots will sooner or later perish under the attacks of the insect. We can, however, replant the vineyard on roots that, while tolerating the insect, suffer nothing or little from its bites. This is the only reliable measure thus far found to be of practical value to those who would grow grapes. While it involves the loss of capital expended in a growing vineyard, it enables us for the future to guard against further loss from the same cause; and, in the case of new plantations, it shuts out the occurrence of the loss. Replanting of European Vines. It is mere folly to plant the Vitis Vinifera, on its own roots, in vineyards where the phylloxera has already destroyed the vines. While it is possible for a full-grown, healthy RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 13 Vinifera to resist the attacks of the phylloxera for several years before perishing, it is not possible for a young, partly rooted, non-resistant vine to live any length of time when planted in soil that is already infected with the insect and somewhat exhausted from years of cultiva- tion. Some imagine that it would be economical to plant the Viniferas in the same place that the dead vine occupied, expecting to get two or three crops from the vine before it perishes. This is a common error in countries infected with the phylloxera, especially at the beginning of the trouble. It has been tried over and over again in all the countries where the vineyards have been destroyed, and, even with many pre- cautions, such as allowing the land to rest for several years, etc., it has ahuays proved a heavy financial loss, even in the richest soils and with the most vigorous varieties. I do not know of a single case, out of the great number of experiments of this sort, that has not proved disastrous from a financial standpoint, even in countries where the value of the crop is greater than in Cali- fornia. The difference in cost between planting on resistant roots and planting on non-resistant roots is so insignificant that, taken with the certainty of having, sooner or later, to go through the same operation of replanting, renders planting non-resistants a most foolish thing to do. Influence on Growth and Crop. It is to be noted, too, that when a Vinifera has been grafted on a variety of resistant vine, perfectly adapted to soil, climate, stock, etc., it will produce heavier crops, sweeter and better- matured grapes, of larger size, than the Vinifera would produce on the same soil were there no phylloxera at all. This alone, aside from the certain loss of capital in the future, would more than pay for the extra expense of planting on resistant roots. When it is observed that a vineyard planted on resistant vines does not produce fully as much as the same varieties did under similar circumstances on non-resistant roots, the conclusion must be that it is not the fault of the resistant itself, but that the wrong adaptation to soil, etc., has been made, just as would obtain if the wrong variety of Vinifera were planted on the same soil. Failures, then, in plantations on resistant roots merely show that the vine-grower has made a mistake which he can rectify by the exercise of a due amount of study and intelligence. Influence on Quality of Wine. It was for a long time asserted that the wine made from Viniferas grafted on the resistant stock was of inferior quality, or would in time acquire some of the disagreeable characteristics of the American grape. Time has proved that the qual- ity of the wine is only affected in so far that perfectly matured grapes give a better product than those imperfectly matured; and as the grapes from grafted vines are, as a rule, better matured than is usually the case on non-resistants, the results are in favor of the grafted vine. It is also to be noted that grafted vineyards are less apt to coulure, or the dropping of the young grapes. Extra Expense of Resistant Stock. It is true that the resistant vines require more care to get them started than the Viniferas, and therein lies one of the heaviest counts against the use of resistant stock. The extra time and expense of grafting and cultivation before the vineyards pay are certainly drawbacks; but as things stand to-day, he who would have a vineyard must encounter resolutely such extra care and expense, or leave the field for some one else who is willing to do the work properly. 14 UNIVERSITY OF CALIFORNIA. Discovery of the Resistance of American Vines. When the phylloxera was first found on the vines of the Old World, some profound thinkers proposed grafting the Vitis Vinifera, or European grape, on the Ameri- can stocks, arguing very correctly that, as the phylloxera had existed from all time on the wild American vines, there must be some quality in these vines that enabled them to resist the attacks of the insect; for there were the wild vines thriving in the forests with the phylloxera on them to prove it. Examination showed that, in Europe, on vineyards attacked by the phylloxera, wherever there was an American vine it alone out of all the vines did not seem to be affected with the deadly dis- ease that was sweeping out of existence millions of dollars' worth of capital. Some of these vines had been grafted, and it was found that they gave abundant and excellent crops where the Viniferas perished. No sooner was this exemption of American vines observed, than the more progressive vine-growers sent to America for cuttings and seeds of the American vines that were found growing wild in the forests. It would be impossible to estimate the number thus imported into the European vineyards, but there were very many shiploads of them. First Attempts at Planting Resistant Vines. Tens of thousands of acres were planted out in American vines, but the results were at first disappointing. Many were found to perish outright, others eked out a feeble existence and finally died even before grafting, while some throve at first and even for a short time after grafting, and then perished. Among all these some were noted that from the first flourished most exceptionally, and, after grafting, yielded heavier crops than had ever been obtained with Viniferas on the same soil. Species and Varieties. This caused close attention to be paid to the species and varieties of the American vines. After a due amount of study and experiment, it was found that in America, instead of having a single species, as in Europe, we have eighteen distinct specieSj grouped as follows: Section I. MUSCADINIA (Planchon). Vitis Rotundifolia (Michaux). Vitis Munsoniana (Simpson). Section II. EUVITIS (Planchon). 1st Series. LABRUSC.E. Vitis Labrusca (Linneeus). 2d Series. LABRUSCOIDE^E. Vitis Californica (Bentham). Vitis Caribaea (de Candolle). Vitis Coriacea (Schuttle worth). Vitis Candicans (Engelmann). 3d Series. AESTIVALES. Vitis Lincecumii (Buckley). Vitis Bicolor (Le Conte). Vitis Aestivalis. 4th Series. CINERASCENTES. Vitis Berlandieri (Planchon). Vitis Cordifolia (Michaux). Vitis Cinerea (Engelmann). 5th Series. RUPESTRES. Vitis Rupestris (Scheele). Vitis Monticola (Buckley). Vitis Arizonica (Engelmann). 6th Series. RIPARIA. Vitis Riparia (Michaux). Vitis Rubra (Michaux). RESISTANT VINES J THEIR SELECTION, ADAPTATION, ETC. 15 From this list, with its grouping, it will be found that the question of American vines is a far more complicated one than at first might appear, especially if it is borne in mind (and too great stress cannot be laid upon the fact) that each of these eighteen species embraces many hundreds of varieties, these varieties differing the one from the other in the same species as much as the " Zinfandel " does from the " Seedless Sultana." The Vitis Vinifera, or the single species of Europe, which furnishes us with our wine- and most of our table-grapes, has over 1,500 varieties. It is possible that there will be found almost as many varie- ties of each one of the eighteen American species in America. In the case of the Vinifera, however, we have the grape berries to help us classify the varieties. With the American resistants we can place little reliance on the berries, as many of them are not eatable, and in a vine- yard the leaf alone is seen for but a year or so; and after that it is cut back and grafted. Hence the difficulty in getting the average vine- grower to familiarize himself with the variations in species and varieties of American resistants. This explains how so many very intelligent vine-growers continually confuse species and variety. This confusion of species with variety has proved the greatest stumbling- block in the path of the modern viticulturist. The inability, or in many cases the unwillingness, to recognize the fact that there are hundreds of varieties of Riparias, etc., and that some are valuable and others are not, has cost the world vast sums of money and has driven many vine- growers into bankruptcy. The burden fell heaviest on the French, who were the first to seriously take up resistants. They have had many years of experience on a large scale, and we are able to profit by their mistakes and successes in planting out our resistant vineyards. At least we should do so; but it is unfortunately true that to-day in this State there are very many who simply refuse even to investigate what others have done. Local experience is necessary, no doubt; but unless it is intelligently directed, vast sums must first be spent before any adequate results are to be had. When certain facts have been estab- lished in many countries beyond a possibility of doubt, it is folly for us to disregard them. I have found that when the experience of others is alluded to it is very often sneeringly thrust aside, with the remark that "We do things differently in California." Just as though "doing things differently" could change a thin-wooded, weak variety into a thick-wooded, vigorous one. It really would seem that many of the vine-growers of this State are disposed to begin experimenting with resistants precisely as the Europeans did, making the same costly mis- takes and utterly disregarding the successes in the way of improved varieties, already achieved. When the Europeans found that some of their imported American cuttings did well, while others perished, they took one step in the right direction by recognizing the fact that there were really material differ- ences existing between American vines. Their scientists told them the names of the species, and pointed out the fact that each species embraces many different varieties. The vineyardists, however, were in such haste to replant their ruined vineyards that they grasped at the names of species, and paid but little attention to the subdivisions of each group. By a system of experimental selection they found that the Vitis (species) Riparia and the Vitis Rupestris were the best all-around groups to select from. The other species were found to be of little or no practical value, 16 UNIVERSITY OF CALIFORNIA. on account of their difficulty of adapting themselves to new conditions, refusal to grow from cuttings, or requiring such special soils, etc., that it was not practically possible to use them. Hence the sixteen other species of American vines will not now be considered at this time, reserving for another place and time a full discussion, from a scientific standpoint, of these species which have but little practical interest for us to-day. Let the reader be assured that it will be idle for him to attempt to improve on the Riparia and Rupestris, except by years of hybridizing, or repro- duction by layering, which is far too long and expensive an operation, except for public experiment stations or fancy vineyardists. A few of the hybrids already made will, in their place, be discussed. Vitis Riparia and Vitis Rupestris. As soon as the fact was established that the Vitis Riparia and Vitis Rupestris were more valuable than the rest of the eighteen species, the European growers did exactly as is being done to-day in California. They sent to the American forests and got any and everything that could be called Riparia or Rupestris. Perhaps one of the most striking mistakes they made was to attempt to reproduce the resistant stocks from seeds. This proved a most dismal failure everywhere, for almost every seedling developed into a new variety of more or less worthless- ness, it being seldom that a grape seedling is as good as the mother- vine. The well-meant advice of some "to go slow" was disregarded, and they planted anything they could get. The result was that tens of thousands of acres had to be dug up, after several years of waiting. Then came the period of doubt, and the revival of the old question, " Do resistants really resist?" In this State, similarly, many entertain serious doubts on this subject. Mysterious diseases are reported that attack one man's vines and leave his neighbors' intact. In some cases a man's Riparias are found to be partly perishing, while others, bought from a different nursery, are doing finely. All this was passed through by the European vine-growers years ago, and it cost them roundly; but they persevered and -finally triumphed over all obstacles, in spite of having far more difficulties to contend with than their California brethren have. By visiting their neighbors, and the government experiment stations, they profited by the lessons each had learned under different conditions, and thus it came about that even the laborers soon learned to become comparative experts in American ampelography. There seems to be a deep-seated objection on the part of many Cali- fornia growers to going into what they are pleased to call "useless details." They want a hard-and-fast rule that will fit all cases, and that will not require any study on their part. The moment it is sug- gested that there are varieties of Riparia or Rupestris, they become impatient and say " That's all well enough for the experts, but there is not time for such details." Yet it became necessary that the most igno- rant peasants abroad should familiarize themselves with these details before the vineyards were sucessfully reconstituted; and they did so, becoming most expert observers and invaluable aids to those more deeply .versed in the science. Instead of relying on nurserymen to do the selecting for them, they procured from those that had the best varieties and propagated their own nursery stock, carefully rejecting all weak RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 17 vines, or such as did not seem to thrive as well as others on their special soil. It was not a case with them of refusing to " send their money out of the country 11 in order to procure for propagating purposes the very best to be had, as is unfortunately the case with many here in California. They did want the best to be had, knowing full well that it was false economy to get inferior stocks when better could be procured, even at a higher price. The patronage of "home products" is perfectly right when the products are as good as can be had elsewhere, but when applied to inferior nursery stock, it is going rather too far. Selection is the great lesson that has been learned in the planting of resistant vines. Now in order to select the best to be had, one may have to go beyond his own vineyard into other vineyards, even if they be situated on the other side of the world. If he cannot go personally, he can at least rely on some one in whom he has confidence, who can; and when once he has a few vigorous vines he can soon propagate enough for himself and his neighbors. In selecting varieties it was found that the geographical analogies between the native habitat of the vine and that of the place where it was to grow had little to do with the problem. What was needed was a variety that was very vigorous and large-wooded, and that was easily suited to new soils and conditions. It is to be remarked that among the many species and their varieties, some are very hard to transplant into other conditions, while others adapt themselves very readily to new condi- tions. Concerning species it has been found that the Riparia and Rupestris, as groups, adapt themselves more readily to changed condi- tions than any of the other American species known. It is perfectly true, however, that the varieties of each of these species differ greatly the one from the other in this respect. There are some Riparia varieties which it seems almost impossible to grow successfully, except under most exceptional conditions. There are otjier Riparia varieties that do remarkably well in the same soils in which other varieties of the same species refuse absolutely to grow. Yet in both cases they are "true Riparias." The expression "true Riparias" is used advisedly, for one of the commonest questions the Department is asked is, "Where can I get a ' true Riparia"?" The point to be made is that there are hundreds of " true Riparias " that are worthless. What has been said in this connection of the Riparia holds good in the case of the Varieties of the Vitis Rupestris. After some years of experiment it was found that the Vitis Riparia was the best all-around group for the majority of European soils. This is shown from the fact that to-day, out of the 2,500,000,000 of vines grafted on resistant stocks in the Old World, probably 1,700,000,000 are grafted on Riparias. The remainder are almost all Rupestris stocks, with some of the best hybrids that the Americans had previously secured. While the Riparia is beyond a" doubt the best species for the average European vineyard land, it by no means follows that the same is true in California. In Europe there are abundant summer rains, except in the hottest parts. With the thorough cultivation given to the soil, the Riparias thrive remarkably well, for there is always sufficient moisture in the soil to keep up the growth of the vine. In California, on the other hand, there is little or no summer rain and in almost all of our vineyards the soil dries out to a considerable depth. As the Riparia, as a group, is naturally shallow-rooted, the state of affairs in California be- 2 RV 18 UNIVERSITY OF CALIFORNIA. comes very different from that on the other side of the ocean. Instead of being the species that one should at once choose, as a general proposition, it becomes the species that one should not choose until careful investiga- tion has been made as to the depth, moisture, and richness of the soil. If there is sufficient natural richness, moisture, and coolness in the soil to keep the shallow-growing roots of the Riparia in good condition all the year round, then it is undoubtedly the species to choose. If there is any doubt about the moisture, coolness, and friability of the soil, then the Rupestris becomes the species to choose in all cases, except where there is an excess of moisture, lime, or compactness. The reason for this is that the Rupestris is a species that grows naturally in dry soils, and sends its roots downward more than the Riparia. It will thrive in a soil that is so dry that any Riparia would inevitably perish. If one will take the trouble to dig out, with care, a Riparia vine that grows side by side with a Rupestris of the same age in a somewhat dry soil, he will at once perceive the difference in the manner of root-growth in each case. Cause of Failures. While it is true that most of the replanted vine- yards in California have been reconstituted with Riparia stock, it is also true that there have been many failures; and doubtless many of the failures thus far noted can be attributable to the selection of the wrong species for the given soil. In many cases it has been found that Riparias have thriven remarkably well on dry, steep hillsides, and this has been advanced as an argument against the idea that Riparias require moist soils. In some of the cases that have been called to the attention of the Department it has been found, on investigation, that the so-called Riparia stock was not Riparia at all, but Rupestris that had been sold by the nurserymen as Riparia, either ignorantly or because the pur- chaser wanted Riparias. While this explanation holds good in some cases, there are others where it will not, and seemingly dry hillsides are keeping Riparias in a remarkably thriving condition. In these cases it has been found that, although the vineyard was on a hillside that seemed dry, yet in reality there was an underdrainage near the surface that supplied the Riparias with ample moisture, the soil being quite fertile. By inves- tigating closely enough there will always be found explanations of the seeming anomalies, that in no way shake the truth of the general rule. Exceptions must be taken into consideration and looked out for with the greatest care. Another cause of failure in soils that to all appearance are " Riparia soils " is that the land was not in proper condition when the stocks were planted. It has already been remarked that the resistant vines require far greater care in planting than is usually given to the Vinifera. The most important point is the proper preparation of the soil before plant- ing. It has been established, beyond the possibility of rational doubt, that before planting American vines 'the land should be given one plowing that is twice as deep as would have been necessary had Vini- feras been planted in the usual manner. This is one of the practical lessons learned abroad. One of the vineyards that is used by the Pro- fessors of the National School of Agriculture in France as the most striking illustration of the necessity of deep plowing, is situated on the banks of the river Herault, on the very best " Riparia soil " in France. When first replanted in resistant stocks no deeper plowing than had been given for the Viniferas was thought necessary. A very large vine- RESISTANT VINES) THEIR SELECTION, ADAPTATION, ETC. 19 yard was planted to Riparias. After several years it was found that they seemed to be total failures. As the soil was a typical Riparia soil, and the variety used was the very best, much interest was aroused. After consultation, it was decided to dig out the entire vineyard, give it a very deep plowing, and replant it with cuttings from the same mother- vines that had supplied the cuttings for the original plantation. This was done, and to-day there is not a finer vineyard in the country. Experi- ence has shown that all American resistants require deep plowing at first, though some do not require quite as deep preparation as others. The Riparias are the most exacting in this respect. It is a safe rule to follow, that the drier and poorer the soil the greater care should be taken to prepare it for the reception of American resistant vines. Hybrids and Direct Producers. Thus far only the pure species, unmixed, have been spoken of, but there are many vines of more or less value that are not pure species, but have been produced, artificially or accidentally, by cross fertilization, or by mixing the pollen of the flowers of two or more species; so that the resulting vine has some of the characteristics of each of the parent vines. The Americans have made the greatest progress in the hybridization of their vines; owing to the fact that in the East the Vitis Vinifera cannot be grown, they were forced to improve the wild vines, so as to have table and other grapes for their own use. Lately the French have taken up the hybridization of vines, and made remarkable progress. The great object at present is to obtain a vine that, while resisting the phylloxera, the two mildews, the black rot, etc. (all of which diseases are natives of America, and which the American vines resist more or less well), will give without grafting a grape that has size, and the quantity and quality of the Vitis Vinifera. The American grapes have all more or less of a peculiar charac- teristic musky flavor (generally called "foxy taste"), that, while more or less agreeable for table-grapes, becomes unpalatable when fermenta- tion has vinified the must. What is wanted is a vine that will have all the qualities of the American vine as regards the growth, but all of the qualities of the European vine as regards the quantity and excellence of the crop. Thus far the goal has not been reached; but in some cases there 'have been approaches to it. At times the "direct producer" (a vine possessing the resisting power in its roots and free from unpleasant flavors) has been favorably spoken of, and in some cases many thou- sands of acres were planted with them, but extended trial proved that they were not to be compared with the Vinifera grafted on a resistant stock. As an example of this may be cited the Lenoir, or "Jacquez " as it is known in Europe. At one time it was extensively planted as a direct producer, but it was found that the crops were unprofitable, on account of small quantity and the inferior quality of the wine; so it was relegated to the place of a grafting stock. It was found, however, that as a stock it could not compare with the selected " standards," Riparia and Rupestris, because after grafting it lost much of the vigor that made it remarkable when ungrafted; besides which it is more difficult to prop- agate from cuttings. The same can be said of most of the hybrids of Vinifera with American vines. They seem to lose to a great extent their vigor when grafted, and even when ungrafted they do not possess the same degree of resistance to the phylloxera as the mother-vine from which the resisting qualities were derived; and it is seldom that they 20 UNIVERSITY OF CALIFORNIA. are entirely free from the " foxy " flavor of the American vine, though when properly adapted they are very vigorous and thick-wooded, which causes many to prefer them to poor varieties of Riparia and Rupes- tris. Among the best-known hybrids we may mention York-Madeira, Catawba, Taylor, Vialla, Lenoir, Doaniana, Norton's Virginia, Autuchon, Isabella, etc. While it is not claimed that the time will not come when some perfect hybrids may be found that will give all the qualities desired either for a stock or direct production, it is certainly true that thus far none have been found the use of which is as satisfactory as grafting the selected varieties of the pure species. It would seem from the results thus far obtained that the perfect hybrid stock may be looked for long before the perfect direct producer is found. The former are greater successes in their way than the latter have been. Investigation will show that most of the favorable reports concerning new hybrids emanate from nurserymen or interested parties, and hence must be taken cum grano sails. Many Americans have been misled by reading scraps from foreign literature concerning resistants. Thus one very common error, so origi- nated, in this State is that certain varieties " require calcareous soils." As a general statement it is true that all American vines dislike strongly cal- careous soils, though some will stand them better than others. In France the soils are, as a rule, far more calcareous than those of this State. The fact that the American vines " fear lime " has caused the vineyardists there great trouble in reconstituting their vineyards. In fact, there are certain regions, such as the Cognac region of France, where it has been found almost impossible to make either the Riparia or Rupestris grow in some of the most famous vineyards of the region. So refractory have most of the American vines proved that the main hope there now seems to lie in the planting of the Vitis Berlandieri of Texas, by means of layers, for it will not grow from cuttings. Whenever Europeans are reported as experimenting with varieties other than the standard Riparia or Rupestris, it is safe to conclude in most cases that the soil is excessively calcareous. STANDARDS OF RESISTANCE. It must be remembered that mere resistance to phylloxera is not the only desideratum in determining the value of a resistant stock. There must be, with the exemption from the effects of the phylloxera, a natural adaptability to soil and climate that will enable the vine to be sufficiently vigorous to support the graft with a sufficient amount of sap to produce and nourish properly a large crop. Nodosities and Tuberosities. A nodosity is the swelling on the very young, tender rootlets of the grapevine, resulting from the sting of the phylloxera. It is the mildest form of the injury to a root of the vine that is noticeable to the examiner. The mere presence of a few of these nodosities on the roots of a vine does not indicate that the vine is not a valuable resistant. In fact, there are but few of the American resistant vines on which nodosities are not found. While it shows that the resist- ance of the vines is not the maximum, it by no means indicates that the vine is not (on account of its ready adaptability) the very vine for the given soil. These nodosities are whitish or pinkish, and resemble somewhat the head and neck of a long-billed bird. The insect causing RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 21 the swelling is, as a rule, to be found in the acute angle formed where the head joins the neck, or in other words, on the throat. There may be a number of insects found on a nodosity, but the insect whose bite caused the swelling will be found in this acute angle. If, however, cancerous patches of decomposition are found on the more fully developed roots, something more serious is threatened, namely a tuber- osity. This indicates that the resistance of the vine is less than was the case where only nodosities were found. Wherever tuberosities are found there also are nodosities, but the reverse is not true. It is cus- tomary to judge of the resistance of a vine by the nature, number, and position of the tuberosities on the roots. When tuberosities are found that produce only a wound, with a scab-like covering of cork, which may, when dry, be scaled off with the finger-nail, there is a very high resisting power; as the cancers become deeper seated and as they appear more numerous on the older roots, the moare does the resisting power of the vine fall. In order to be able to indicate with some degree of definiteness the resistance to the phylloxera (not the value as a stock), an arbitrary scale has been provisionally adopted by the scientists and practicians of the entire viticultural world. In this scale the maximum of resist- ance is taken as 20, and the minimum as 0. Thus, the resisting power of the best Riparia is indicated by 19.50, and that of the Lenoir (a hybrid) as 12, the best Rupestris varieties, 19.50, etc. From this it will be seen that the injury the phylloxera does to the vine is not the loss of sap, for that is infinitesimal, but the decay of the roots, thus depriving the vine of its supply of nourishment. Also, that if an old, vigorous vine be attacked, it may take many years to destroy the roots, they being very large and well developed; and the vine will endeavor to throw out new roots as fast as the old ones become enfeebled. With a young vine, on the contrary, the root-system is not large, and the cancers speedily so wreck the root- system that it cannot support the life of the vine. Examples of Resistant Standards. The importance of the fact was strongly impressed upon the writer from personal observation of the instance given by Prof. Pierre Viala, of the Institut Agronomique, France, in his excellent work on "Adaptation." In a collection of American vines at the National School of Agriculture, of Montpellier, in one of the worst parts of the plot, there are, side by side, their roots interlacing, some Rupestris, Solonis, Cornucopia, etc. The Rupestris shows but few nodosities, no tuberosities at all, and its resistance may be indicated by the figure 18 out of a possible 20. The Solonis, besides a great number of nodosities, shows on the older roots a number of tuberosities not very dangerous in appearance, which seldom reach as far as the main roots. Its resistance is indicated by the number 15. The roots of the Cornucopia are covered with large nodosities and tuberosities very prominent in character, and give a resistance of 4. These were planted sixteen years ago. If the phylloxera were the only factor in the problem, their exterior vegetation should indicate 18:15:4. As a matter of fact, however, the reverse is the case. The Rupestris, upon which the phylloxera causes no damage whatever, is stunted and yellow and almost in a dying condition, so that its exterior vegetation may be described by 2 out of a possible 20. The Solonis, although 22 UNIVERSITY OF CALIFORNIA. suffering slightly from the attacks of the phylloxera, is less feeble than the Rupestris, and its growth can be fairly indicated by 4 out of a possi- ble 20. The Cornucopia, on the contrary, though badly attacked by the phylloxera, is comparatively vigorous, its exterior growth being equal to about 15 out of a possible 20. This same anomaly is noted in the case of other vines, such as the Othello, Autuchon, Canada, etc., which, even though badly attacked by the phylloxera, sometimes do better than the Rupestris, Riparia, etc., of higher absolute resistance on certain soils. CHARACTER OF LAND FOR RESISTANT VINES. The question then presents itself to the vine-grower: Given a certain soil and climate, what resistant stock should be chosen? For it is, at this state of knowledge of the phylloxera, sheer folly to attempt to plant out a vineyard of non-resistant roots in place of one that has already been destroyed by the insect. It is very true that to-day there are many vine-growers, who, while expecting sooner or later to lose their vine- yards, labor under the delusion that they can get several crops before the phylloxera destroys their second planting. This has been tried the world over, and also in this State, and in every case has proved a bad failure. If any one is going to plant a vine, let him plant one that will not have to be replaced in the course of three or four years. He will have other enemies enough to contend with without laying himself open to one of the most terrible of insect pests known. In silicious clay soils that contain but a moderate amount of lime, all of the American vines will thrive more or less well. They present in their development, fructification, etc., certain differences which it behooves one to keep in mind. Not that in such soils they would prove a com- plete failure; but as the cost of planting a vineyard is great, it is very necessary to take into consideration all the requirements and adapta- tions of each one, in order to obtain the best possible results instead of merely fair ones. In other words, the question is whether we shall do the best that nature permits, or be content with a great deal less than another man gets with the same effort. Excessively Calcareous Soils. In soils in which the lime is largely in excess, things are different. Here nearly all the American vines, and even some varieties of the Vitis Vinifera, behave badly. Observation and experience have established the fact that for every soil there exists an American vine that will produce better results than any other, and it should be the endeavor to find it in order to get the best results from the soil, for it is just as expensive to plant a poor vine as a perfect one. Whatever be the conditions in wine-making to-day, the time will surely come when the industry will be profitable only to those who get the maximum returns from their vines, and it is beyond all dispute that those who have planted inferior stocks cannot attain this end. They will, when competition with properly planted vineyards begins, be driven out of business, so that the sooner this state of affairs is duly appre- ciated, the sooner wine-making in California will be established on a sound basis. As has been shown, it is established beyond possibility of rational doubt, that the soil is one of the principal factors in the problem of reconstituting vineyards destroyed by the phylloxera. RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 23 As regards soils designated as silicious clays or loams, all that is to be considered is their compactness, humidity, and fertility. The impor- tance lies in physical effects produced by a greater or less admixture of sand, clay, etc., thus giving greater or less compactness, etc. Silicious sands containing a quantity less than 8% of clay, are classed as "light soils." The Vitis Vinifera, or European vine, does well in such soils, without attaining extraordinary development; it may be said to develop normally. This is not the case with the American vines, however. Some few American resistants, hybrids or otherwise, such as the Lenoir, Herbemont, Vialla, Rupestris, St. Georges, etc., produce in them, in France, a vegetation that leaves little to be desired; while the Riparia and some others give but a feeble growth. Compactness. The compactness of the soil is due sometimes to an excess of clay, sometimes to an excess of fine silicious sand. In the last case, when the amount of clay is less than 5% or 6%, the soil is excessively hard and compact after the dry weather sets in; so much so that the roots of the vine have great difficulty in penetrating the soil, and the whole vine thrives badly. An excess of clay would seem to be less harmful than an excess of fine silicious sand or silt. Too great com- pactness of the soil is a serious drawback to the well-being of the vine, which, like many other plants, prefers a friable, light, warm soil; and the results obtained are more satisfactory in proportion as these condi- tions are more perfectly realized. It is true that while some of the resistants will grow in the most compact soils, yet they never attain their maximum vigor; while the life of the vine is notably shortened. In such cases the American vines behave somewhat as do the Viniferas; but some among them would seem to resist such soils more than others. Thus, the Riparia and the Rupestris do very poorly in compact soils, while the Lenoir, the Herbemont, and the Vialla accommodate them- selves better to such conditions. Each of these vines will be discussed more fully from this point of view, but the reasons for these differences will be given here; it does not suffice merely to note facts, the causes and general results must be looked for. The Riparias and the greater part of the Rupestris varieties have sparse root-systems, with slender roots; but these roots are very hard and much ramified, being terminated by an abundant growth of very tena- cious root hairs. The Lenoir, the Vialla, the Herbemont, the Cunning- ham, the Cinerea, the York-Maderia, etc., have, on the contrary, larger and stronger roots with less root hairs on them. The Vitis Vinifera and Lenoir, vines that thrive so well on all kinds of soils, have also quite large, thick roots. Just why the vines having the thickest and fleshiest soft roots should seem to penetrate more readily into very hard, compact soils than those with slim, slender, very hard roots, is not fully understood as yet. It may be that the greater strength of the larger roots enables them to force their way into compact subsoils by sheer force of weight or mass. But whatever be the true cause, the fact remains constant and deserves to be noted. It shows that the American species, pure or hybridized among themselves (such hybrids are called Americo-American, while those that are hybridized with the Vitis Vini- fera are called Franco-American, the French having made the most complete study of them thus far), as well as the Franco- American hybrids, which inherit strength and size of root from the Vitis Vinifera, 24 UNIVERSITY OF CALIFORNIA. will develop vigorously in compact soils, as they have a powerful root- system. Years of experiment have established this fact beyond the possibility of dispute. Humidity. The humidity of the soil exercises considerable influence upon the vegetation of the vine. An excess of humidity is very favor- able for the development of fungous diseases, coulure, etc.; besides this, it checks the proper development of the root-system. Plants growing in a very moist soil frequently seem to give a more luxurious external vegetation than those growing on drier soils. In such cases the root- system is always more feeble than would have been the case had the soil been less moist. This phenomenon is not peculiar to the vine, but is observed with all plants. The root-system is always more developed in dry soils (without excess, of course), because of the vine being forced to seek moisture at a greater depth. It would seem, therefore, that in dry soils such as may be said to be characteristic in the majority of Califor- nia vineyards, the root-system must be very well developed, as its enfeeblement counts heavily against the plant. It is, therefore, apparent that on the dry soils of this State vines should be planted whose resist- ance to the phylloxera is above the average. This consideration is independent of other complicating considerations. For dry, gravelly, or sandy soils only such species must be chosen as give a high resisting power and well-developed root-systems. An excess of water in the soil presents another difficulty. Young vines planted under such conditions will scarcely root at all, and though they may give at first seemingly a good top-growth, yet when dry weather comes they generally perish or suffer to such an extent that it is impossible to get from them normal results. Humidity acts frequently in conjunction with compactness, as it does with coldness, of the soil. The latter, however, generally is the result of the two former. This combination of compactness, humidity, and coldness of the soil will delay the starting of the growth in spring, and thus injure the timely nourishment power of the vine. Fertility. Fertility is a powerful adjunct of the proper vegetation of all plants; the more fertile a soil is, the better will be the vegetation thereon. However, very great fertility of the soil is not necessary for all kinds of American vines. The Rupestris is, perhaps, the species which thrives the best in poor soils, especially if tending to dryness. It attains considerable dimensions and supports the graft very well under conditions in which other vines would scarcely grow at all. The Riparia is far more exacting in this respect. The Lenoir and Herbemont accommodate themselves very well to poor soils. Such are the principal conditions which influence the vegetation and development of the vine in the generality of soils, such as are to be dealt with in this State. As has been said, it will not be profitable to compli- cate the study of the adaptation of resistants in this State at the present time, with the numberless exceptions that arise when one has to deal with soils in which there is a large excess of lime. There are few such soils in the viticultural regions, so the consideration of these complica- tions will be deferred to a more profitable time. The general considerations given above are, of course, easily modified to suit particular cases. Lightness of the soil and, in consequence, permea- RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 25 bility, being necessary for the proper vegetation of the vine; exceedingly deep plowing, green or straw manuring, etc., may be made to sensibly modify the compactness and coldness. Drainage will be the remedy in cases of too great moisture, while moderate irrigation with good cultivation will supply any deficiency in moisture. In all cases, however, it is to be noted that too great care in the cultivation of the soil cannot be given. It is a sad fact that in California, with its mostly rich, friable soils and exceptionally good agricultural machinery, vineyardists very t>ften shamefully neglect the cultivation of their vineyards, and then complain because the results hoped for do not materialize. There are far too many viticulturists (and horticulturists, too) who, even in heavy soils, attempt to make one shallow, ill-timed plowing do for the whole season. Others there are who attempt to make irrigation take the place of cultivation. There are on record at the Experiment Station cases where some very fine orchards and vineyards have perished from this cause. There are others where the vines died merely from drying-out, due to poor cultiva- tion. Some seem to imagine that the cultivation of the soil that might be suitable for an old, thrifty vineyard will be equally well suited to a very young one, forgetting that the very young vines have but a very small root-system developed as yet. Some of the reported failures of resistant stocks have been found to be due purely to this cause. Preparation of the Ground. Here, again, attention must be called to a fact that has been well established the world over; namely, that all American vines must have deeper and better cultivation in starting than the Vitis Vinifera, or European vine. This is not a theory, but a fact too well established under the greatest variety'of conditions to be con- troverted. There are in this State some striking examples of the good effect of extra deep plowing before planting out American vines. Too great stress cannot be laid on this necessity of deep preparatory plowing. Especially is this necessary in California on lands that, while not being especially dry, are apt to dry down considerably in summer. It is especially necessary with the Riparias and those resistant vines that tend to throw out their roots horizontally, instead of downward, as is the case with the Rupestris. But even the Rupestris requires deep plowing in order to give it a good start. Professor Viala says that very deep plowing of land destined to be planted in American vines will advance crop-bearing from one to two years; and the facts certainly bear out this statement. Those who cannot give their vineyard land a plow- ing twice as deep as is usually given, no matter what be the fertility of the soil, are advised not to plant American vines, or any other kind. QUARANTINE AND DISINFECTION. From what has been said in this connection, as well as under the head of submersion, it will be seen in what a "fool's paradise" those are dwelling who, on slightly sandy soils well mixed with clay, say that they " have nothing to fear from the phylloxera " when it reaches them, as it surely will, sooner or later. There are many regions of this State, as yet uninfected with the phylloxera, where irrigation is extensively practiced, and where the soils are more or less of a sandy nature. The vine-growers of these regions refuse to believe that they have anything to fear. They may rest assured that they have no ground for such 26 UNIVERSITY OF CALIFORNIA. hope, and at the same time are recommended to place all possible safe- guards around their vineyards in the way of quarantine regulations. In this way they can delay the advent of the phylloxera, but cannot hope to be free from it forever. While the winged form of the phyl- loxera is rare in California, it is a fact that it does exist; and hence there is no possibility of the insect becoming extinct, as is claimed by some. The winged form is not the one most dangerous for infection, except in adjoining vineyards with no trees or hills between. Infection of regions generally is due to the gall form or the root form, or the eggs of one or both. Hence, too great care cannot be taken in avoiding the introduction of undisinfected cuttings, boxes, packing material, etc., on which the insects or their eggs might find a lodging-place. Cuttings can readily be thoroughly disinfected, while it is almost impossible to sufficiently disinfect rooted vines without destroying the greater part of them. The sooner the vine-growers who have not yet the phylloxera in their vineyards make up their minds that it is but a question of time before they will, and act accordingly, the better it will be for them. It was disregard of such warnings that caused the backward state of affairs existing in the regions now being replanted in this State. DESCRIPTION OF RESISTANT VINES. VITIS RUPESTRIS. General Characteristics. This species gives a vigorous, bushy vine, with a short, thick, strong trunk; wood of the year (one year old) is dark reddish-brown, sometimes clear, shiny, chestnut-colored; tendrils are discontinuous. The leaves when young are transparent and brilliant, and of a russet red; when old they are small, wider than long, not lobed, and are folded together so as to form a gutter, glabrous and thick. The sinus of the petiole is open and scarcely perceptible; it has well-marked, wide, obtuse-teeth serration. The upper surface is deep green and shiny, lower surface is of a clearer varnished green. Bunch small, with small, spherical, violet-black berries, the interior of which is highly colored. The roots are long, slender, and very hard, but some- times large and fleshy, as is the case with the "Rupestris du Lot." Varieties. The varieties of the Vitis Rupestris are very numerous. Mr. H. Jaeger, who was the first to study the variations of the wild Rupestris, has succeeded in isolating over a hundred types. Millardet was the first to call attention to the great value of the Rupestris as a stock, but from the first importations of American vines into France the Rupestris was quietly experimented with till about 1882, when its true value was noted by Professor Millardet. It may be said that more forms of the wild Rupestris have been found than is the case with any other American species. Abroad, the inferior varieties of the Rupestris speed- ily gave place to the more vigorous ones, for, as is the case with the Riparia, as well as all stocks, only the most vigorous should be used. As a general rule, it may be said that the characteristics of the valuable forms of the Rupestris are very great vigor, strong trunk and canes, with thick 3 shiny RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 27 leaves. One should rigorously reject and destroy all varieties having pale green or yellowish, thin leaves. As is the case with the use of all inferior varieties, one courts certain financial loss if such varieties are tried. The selection of only the very strongest growers is perhaps more necessary for the Rupestris than is the case with the Riparia. The Vitis Rupestris is divided into two main groups, classed accord- ing to the characters of the leaves. The first group comprises all those varieties whose leaves are quite (comparatively) small; their manner of growth is generally more bushy than those of the other groups. This first grand division may be subdivided into: (1) Varieties that are very bushy growers, with very numerous secondary and tertiary ramifications. The main branches are relatively short. The leaves are very much folded together, with parallel edges almost touching, so situated as to resemble tiles on a roof. They are frequently dull colored on the superior surface and of a yellowish- green on the inferior surface. These forms are not vigorous, and the leaves are apt to fall, becoming honeycombed, with small black spots (melanose) . As a general rule, this form should be rejected. (2) A group of Rupestris which embraces the most vigorous forms, with very large trunks, and principal canes that are less trailing, but with strong and numerous secondary ramifications. The leaves of this group are of medium dimensions in ordinary fertile soils, and are shiny on each surface. Among the best known varieties of this group we may mention the Rupestris Mission, Rupestris du Lot, Rupestris Ganzin, etc. The second grand 'division comprises all the large-leaved Rupestris; larger leaved than those of the preceding group when grown on the same kind of soil. They are of bushy growth, and the ramifications are less numerous than those of the preceding. The leaves, while folded together, are more open than in the first grand division. Most all of the Rupestris of this group are very vigorous and large wooded, and are subdivided into: (1) Large, thick-leaved varieties, with the superior surface of a quite deep green color and wrinkled. Example: Rupestris Metallica, Violet- leaved Rupestris, etc. (2) Varieties with large, fleshy, shiny leaves, whose edges are quite open, and whose surface is sometimes quite wrinkled between the prin- cipal and secondary nerves. Example: Rupestris Ecole, Rupestris Fort Worth, etc. (3) Varieties that have very large, fleshy, almost flat leaves, which are almost as wide as long. These kinds do not grow as bushy as the preceding groups, and would certainly seem to be hybrids of some kind with other species. They are commonly considered, however, as pure Rupestris. Examples: Kansas Rupestris, Rupestris No. 62 of Jaeger's catalogue, etc. Prof. Pierre Viala, of the Institut Agronomique of France, from whose lectures and most valuable book on "Adaptation " we have taken much that is valuable in this bulletin, has given the following resisting power to the better known Rupestris varieties: (The maximum perfection is 20.) Resistance. Rupestris Mission 18 Rupestris du Lot _ _ _ . 16 Rupestris Ganzin 18 Rupestris Martin... 18 The Violet-Leaved Rupestris 18 28 UNIVERSITY OF CALIFORNIA. Resistance. Rupestris Metallica 16 Rupestris Ecole 18 Rupestris of Kansas 18 Rupestris of Fort Worth, Texas - 18 Rupestris No. 62 of Jaeger's Catalogue _. 16 Rupestris "Y" 18 Celeburne (Texas) Rupestris 16 Rupestris No. 64 18 Rupestris No. 65 17 The above are a few of the best known varieties of the Rupestris; but as we have remarked, the mere resistance to the phylloxera does not, in all cases, determine the true value of the variety in question. Still, it is one of the most important factors in the problem. This point cannot be brought out too strongly, for too much money has been absolutely lost from the neglect to consider the resisting power of the variety one would employ in the planting of a vineyard, especially when there have been vines destroyed by the phylloxera on the same soil. With resistance to the phylloxera must be taken into consideration the adap- tability of the variety in question. These forms have been chosen by the University of California, for introduction into California, from the mass of Rupestris varieties, as much for their adaptability as for their resistance. Among these some are found that, though they do not possess as much absolute resistance as others, yet, on account of their easy adaptability, they are in many cases as highly esteemed as those which have a higher resisting power. It is for this reason that in selecting from the one hundred and fifty and more varieties of Rupestris to intro- duce into California, the University selected the Rupestris St. Georges. Not that it is very much better than the other good varieties, but as it is the object of the University to establish as a fact that which is denied by many in California, namely, that there are varieties of all the species of American vines some of which are better than others, and if an inferior variety is selected money will be lost. It is confidently believed that, as soon as the vine-growers come to a realization of the fact that there are good and bad varieties, and that bad varieties mean loss, and the good varieties mean profit, they will at once attend to the importation of the other good varieties. The Rupestris St. Georges was selected from the list just given for the reason that it suckers less than the others, is an erect grower, and, above all, is a variety that will grow in a greater variety of soils and climates than most of the others. It is within the range of prob- ability that there may be other varieties of the Rupestris that will be, as a whole, better suited to California conditions than the Rupestris St. Georges, but as at the present moment the Station is trying to establish a custom (selection of varieties of species), the most vigorous grower and likely variety has been selected, proposing, in the near future, to supply those who wish to try them, with other varieties that may do better, and will feel more than satisfied if the present varieties of resistants can but be improved upon, even if the very best has not been secured. It is very certain that the Rupestris St. Georges is a more vigorous grower and thicker wooded than any of the Rupestris thus far found in this State. While, for various reasons, it is in this bulletin called Rupestris St. Georges, it must be remembered that it has many other names, such as the " Rupestris Phenomene," " Rupestris Phe- nomene du Lot," "Rupestris Sijas," "Rupestris Monticloa," "Rupestris RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 29 St. Georges erige," etc. These are synonyms that are fully recognized on the market, so that the same variety will always be obtained under any of these names. The name of " Rupestris St. Georges " has been chosen for many reasons, but chiefly in order to avoid confusion in the future. As soon as the California vine-grower has been convinced that he must use only selected varieties in the replanting of his vineyard, full descrip- tions of the various varieties of the Vitis Rupestris will be given, so that the refinements of the problem may be taken into consideration. As already said, it is thought that in the majority of California soils the Rupestris will have to be relied on rather than the Riparia, as is the case in Europe. Hence it has been given the first place on the list, in the belief that the absence of summer rains, and the abundance of light gravelly or sandy soils, will require in all but exceptional cases, this hardy, vigorous grower. While it does not graft quite so readily as the Riparia, and needs careful suckering for the first few years, yet it will do so much better than the Riparia on similar dry soils that there can be no question about the gain in quantity and quality of crops. It must be remembered that the native habitat of the Vitis Rupestris differs from that of the Vitis Riparia, in that, instead of seeking the moist, shady banks of streams or the depths of forests, it is found in the open, dry beds of ravines, plunging its hardy, deep roots into soils that are but little better than gravel piles, without shelter of any kind. In such soils the Vitis Riparia can scarcely exist, and if it does succeed in struggling along, it is so feeble that diseases of any kind will kill it. The native habitat of the Vitis Rupestris embraces soils that are far more arid and poor than any of the vineyard land in California. While it flourishes in most excessive heat that would be very harmful to other species, it will stand excessive cold very well. This was proved in France (near Lyons) in the exceptional winter of 1890-91. And though it is said by many that the " experience of Frenchmen should be disre- garded, because our conditions are different," it would seem common sense that if a certain variety of vine will stand cold and be thick-wooded when transplanted into France, there is no reason why it should not be thick-wooded and stand the same amount of cold in California or any other country into which it is carried. It has been proved beyond the possibility of rational doubt that the Vitis Rupestris does equally well in France as it does in its native habitat in the eastern part of the United States, provided the soils are similar. There is no doubt, there- fore, that if it is planted in similar soils in California, for it is not a native of California, it will thrive equally well. It is certain that it will not do as well as the Vitis Riparia when planted in compact clay or adobe soils, and if the clay or adobe be in great excess, and especially compact, even the Vitis Riparia will have to be substituted by the hybrid Lenoir, or Solonis, or some other similar hybrid. The Vitis Rupestris, then, is a species that should be selected for all soils that are gravelly, sandy, and dry. The most important item in this list is the drought, for while the Vitis Riparia will do well in moist soils of almost all kinds, it will not do well, if at all, in dry soils, in which the Rupestris will thrive. On moist soils the Rupestris will thrive, but other things being equal, the Riparia will do better on rich, moist land, especially if there be much sand mixed with it. 30 UNIVERSITY OF CALIFORNIA. Thus it will be seen that in selecting the species of resistant vines to plant, more attention should be given to the physical condition of the soil than to the chemical composition; there is one exception, and that is in the case of an excessive amount of calcareous material, in which neither the Rupestris nor the Riparia will thrive as well as some of the other American species, such as the Vitis Berlandierij which though very vigorous, etc., will not grow from a cutting. Prof. Viala, undoubtedly the greatest living authority on viticulture, says: "Among the diverse forms of the Rupestris we recommend the fol- lowing from a strictly practical point of view as the most valuable in replanting vineyards: Rupestris St. Georges, Rupestris Martin, Rupestris Mission, and Rupestris Ganzin. These alone should remain under culture. The others, though possessing a certain undoubted value, are inferior, because they lack resistance or all-around adaptability. The Rupestris Martin, on account of its great resistance to the phylloxera, should always be used in poor, silicious, gravelly soils, with or without a considerable amount of lime. The Rupestris St. Georges replaces actually the Lenoir and Solonis in poor calcareous soils, where formerly the Vialla, Lenoir, etc., were used. The ungrafted Rupestris will frequently show an alarming number of black spots on the leaves, so abundant in some cases as to cause the dropping of a few of them. This is due to the melanose, a disease of the vine that never does any harm at all, and should alarm no one. As soon as the Rupestris is grafted this will dis- appear from the vineyards, as it can scarcely live on the Vitis Vinifera, but takes more kindly to the American vines." VITIS RIPARIA. This is undoubtedly one of the most valuable species of the American vines for the all-around reconstitution of the vineyards of the world. Its chief value lies in its ready adaptability to a greater number of soils than almost any other species. There are undoubtedly others that have a greater resistance to the phylloxera and greater vigor, but they either refuse to grow from cuttings, or they require soils of such a special nature that, when taken away from their native habitat, they refuse to thrive. In the outset of the selection of American resistants in 1874, Prof. Millardet, of the University of Bordeaux, called attention to the remark- able qualities of the Vitis Riparia. Since then his predictions, as in the case of the Vitis Rupestris, have been verified. There is probably no other American species that is as widely scattered in America on a greater diversity of soils and in all climates as the Vitis Riparia. It was this that led to its being experimented with so carefully. Its greatest recommendation is its ready adaptability, growing as it does on almost any kind of soil and standing extreme heat as well as cold. The Vitis Cordifolia and Vitis Rotundifolia are certainly more resistant and more vigorous than the Riparia, but as they refuse to grow from cuttings and require only the most special soils and climates, they of course cannot be compared with the Riparia. The one weak point of the Riparia is its insistence on moisture and a certain amount of richness and fertility in the soil. It is this that will probably make it less valuable for the majority of California soils than it has proved itself to be in Europe. Undoubtedly, when the Riparia RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 31 is well suited to the soil it is better than any other known resistant, and should be preferred to either the Vitis Rupestris or any of the hybrids, such as the Lenoir, Herbemont, Solonis, Doaniana, Clinton, etc. The great problem is to determine the nature of the soil, and be sure that there is fertility, depth, and moisture enough to suit the Riparia. The physical conditions and the absence of much lime are the only special points that should be considered in the suitability of a soil for Riparia. Thus far the Riparia has been spoken of as a whole species, but the point must be emphasized that there are varieties of Riparia that should never be planted under any circumstances. All weak, thin-wooded Riparias should be avoided, as the planting of feeble resistant stock means certain loss of the capital used in planting them as well as the subsequent cul- tivation of the soil till the fact becomes so apparent that the digging up of the vineyard thus planted is necessitated. In this State there are, undoubtedly, all of the varieties of the Riparia existing in the vineyards, but none of them have been classified or named, and vineyardists propa- gate indiscriminately from all these varieties that are mixed up together. This is so true that there are quite few who really believe that there are such divisions as varieties of Riparia. In order to illustrate the fact, the following groupings of type forms are given not merely varieties, but types, each type embracing many varieties: I. TOMENTOSE RlPAKIAS. (1) Large-leaved. Examples of varieties of this sub-group: Riparia Scribner, Riparia Giant, Violet Riparia, etc. (2) Small-leaved. (All of these should be rejected as worthless.) II. GLABROUS RIPARIAS. (1) Lobed leaves. Example: Riparia Palmata, etc. (2) Entire leaves. This group is subdivided into : (A) Small-leaved Riparias ; (B) Large-leaved Riparias, while "B " is further subdivided into : (a) Dull-colored leaves ; (a') Thin-leaved Riparias ; (a") Thick-leaved Riparias. Example: Riparia Baron Perrier, Riparia with, Bronze shoots, Violet-wooded Riparias, Riparia No. 6 and No. 12 of Meissner's Catalogue, etc. (6) Shiny, thick-leaved Riparias ; (6') Round-leaved Riparias (Exam- ple : Riparia of Indian Territory); (6") Elongated-leaved Riparias (Example : Riparia Gloire de Montpellier, Riparia Scupernong, Riparia Grande Glabre, etc.). From these groups of types it will be seen what a problem the student of American vines has before him. Fortunately for the people of Cali- fornia the problem is almost completely solved. There is no necessity to send to the native forests and get hundreds of thousands of cuttings, and experiment with them for years, to find out the groupings and characteristics of each group and sub-group. The vineyardist can profit by the quarter of a century of vast labor and experiment expended on the problem by those who have made a success of 2,500,000,000 of resistants. All that is to be done is to send to France and ask for one or more of the approved varieties that have certain definite and known characteristics, and begin to experiment- then where the French left off. One can then simplify his studies by having varieties before his eyes, which are definitely named and their qualities known. In spite of this opportunity to profit by the costly experiments of others, most of the California vine-growers refuse to do so. They insist on sending to the forests and getting what chance throws in their way. They may get a good variety the first time, but the truth is, that they get a good one 32 UNIVERSITY OF CALIFORNIA. once in ten thousand times. Any one who has been in the forests where these vines grow, will find in some cases two or more distinct species climbing on the same tree. Now these species hybridize naturally, and the seedlings that grow around are mere nondescripts, neither Riparias nor Rupestris. As the cuttings are gathered when the leaves have fallen, even the chance of getting the correct species is problematical. It is very simple to get a few tried varieties and plant them near a stream or in a garden where they can be forced to go to wood, and in a very short time plant out a large vineyard with something that is defi- nitely known. This is what the foreign vine-growers do, and they have eliminated a great many uncertainties from the problem. In California there is, under the present regime, nothing certain to serve as a guide. The soils must be studied and their general characteristics determined, as the Europeans have done. This is quite simple, but vine-growers plant, they know not what, and if that fails, do not try something that has certain well-defined characteristics, but go on blindly planting vines of whose characteristics they are in perfect ignorance. It is the object of the University to establish the fact that the vine- grower can reduce the chances of failure and loss of money to a minimum as soon as he will plant only good varieties. To make a beginning, it has attempted at first not to confuse the minds of those who would study the problem by the introduction of a number of varieties. They will come later. At the present time the Station has introduced, reim- portedj three of the best known and most generally planted varieties of Riparia, feeling confident that once the vine-grower has seen the selected Riparia planted by the side of the nondescript from Nebraska, he will abandon the present system of trusting to kind Providence to do every- thing for him, and will help himself. There are to-day, in this State, examples of the selected Riparias growing alongside of the nondescripts, under exactly similar conditions, and those who doubt should go to see them. The most striking example is to be found on the place of John Swett & Son, near Martinez, in Contra Costa County. The varieties of Riparia that the University have imported are Riparia Gloire de Montpellier, Riparia Grande Glabre, and Riparia Martin. These were chosen for their great resistance to the phylloxera, and especially for their characteristic of being easily suited in a very great variety of soils. Below is given a table in which the comparative value of these will in part be shown. In the scale adopted, 20 is taken as the highest possible number df points in the determination of its value: Resistance. Vigor. Riparia Scribner ._ _. 18 20 Riparia Gloire de Montpellier _. 18 20 Riparia Grande Glabre 18 20 Riparia Martin _. _ 18 20 Riparia Scupernong _ ^ _ 18 17 Riparia Baron Perrier . 18 16 Giant Toinentose _ _. 18 19 This table was made out from a comparison of the various varieties of Riparia growing under favorable circumstances. It is probable that under more unfavorable conditions the vigor of the Grande Glabre and the Gloire de Montpellier would be increased. One advantage the Riparia has over the Rupestris is that it is more easily grafted when old than the Rupestris. In this State, where vine- yardists still insist on planting the cuttings in place instead of in RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 33 nursery, they are more apt to get better results from grafting old Ripa- rias. It is hoped that the day is not far distant when a cutting will never be planted in place, but that there will be varieties which give such large canes that the cutting can be grafted and planted in the nursery; and when it has rooted, joint can be examined, imperfectly grafted vines rejected, and only uniformly perfect vines planted. In this way a paying crop will be gotten two years sooner than under the present system. I know full well that there are very distinguished men in the State who say that they have tried it and failed, and hence conclude that everybody else will fail. The fact remains that there are tens of thousands of vine-growers the world over who have tried it and have made a success of it; so much so that they practice no other system. Attention is called to the fact that in those countries where cutting- grafting is now successful, when it was first suggested, there were many who said that "they had tried it and failed," but others tried it and now all of the vine-growers use this system and no other. The point intended to be emphasized is that nurseries for vines and cutting-grafting are no longer unestablished theories, but solid facts. It is perfectly true that, for a slipshod farmer, the old system of place planting and grafting presents fewer difficulties, but for one who would get the maximum from his capital, and that as soon as Nature allows, the cutting-graft is the better. There are many things that have to be taken into account. Cuttings must not be allowed to dry out, nor must they be drowned with irrigation; nor must the scions be cut one day and exposed to the wind and sun for twenty-four hours, as I have seen it done. The cuttings as soon as cut, should be grafted and put care- fully away in moist sand and not be exposed to the inclemencies of the weather. Finally, the nursery must be properly cultivated and closely watched, and not trusted to the tender mercies of a Chinaman who knows nothing about what he is caring for. If one will give the proper attention to these details he will find that cutting-grafting and nursery- ing pays, but, if he cannot give all of these attentions to the cutting, he had far better continue in the good old way, planting cuttings in place, leav- ing them three or more years, and then grafting. The following letter is interesting in connection with Riparias; but the same differences between selected and non-selected vines occur with all the American species. The letter is self-explanatory: HILL GIRT VINEYARD, JOHN SWETT & SON, { MARTINEZ, CONTRA COSTA COUNTY, CAL., December 20, 1896. f A. P. HAYNE, ESQ., Berkeley, Gal.: DEAR SIR: The question of the adaptation to particular soils, of different varieties of resistant vines, I consider to be a matter of the first importance. I have planted a large number of various varieties of resistants, and intend to keep careful records of their growth and adaptation to our soil and climate here in the Amambra Valley. I have found such a great difference in the growth of the various varieties of Riparia, that I want to call your attention to results. I have found, in talking with many grape- growers, both in this county and elsewhere, that the impression seems to prevail that there is only one variety of Riparia, and that it is all nonsense to talk about different varieties of the species. I would like to have some of the so-called "practical people" who talk this way examine the different Riparias we have growing here. For instance, "I have growing, side by side in nursery, several thousand each of Riparias, imported last spring from Nebraska by the Viticultural Commission, and others obtained from vineyards near Judge Stanley's place in Napa, and said to be of the same stock as his vines. Both sorts were planted at the same time, in the same manner, and by the same laborers. The soil is uniform throughout the patch a yellow, sandy wash soil, fairly retentive of moisture. When the vines started out in the spring, the Nebraska Riparia seemed slightly stockier and stronger growing. The leaves were slightly larger, and in the month of 3 RV 34 UNIVERSITY OF CALIFORNIA. July, though the canes were not quite as long as the canes on the Napa Riparia, I think tha^t the growth of wood was of about equal weight. But in August, the difference in "adaptation" began to show. When the long, hot, dry days came on, although the ground was still moist and in good condition, the Nebraska vines stopped growing. They did not get scorched, nor sunburned, nor sick, but they simply remained station- ary. Their season of growth came to a sudden end. I do not doubt that frequent irri- gation would have kept them growing, but as we do not propose to plant a vineyard that will require irrigation, we thought it best to let them alone. On the other hand, the Napa Riparia kept on steadily growing until the frost came. I have measured the growth of wood on adjoining rows of the two kinds of vines, and I give you some of the figures to show how they run : Length of Canes. Nebraska Riparia. Napa Riparia. (Unselected variety.) (Practically selected varieties.) 10 inches. 34 inches. 11 inches. 44 inches. 20 inches. 40 inches. 13 inches. 48 inches. 18 inches. 24 inches. 24 inches. 61 inches. 13 inches. 52 inches. 19 inches. 72 inches. 20 inches. 51 inches. 36 inches. 72 inches. 24 inches. 44 inches. 28 inches. 12 inches. Average growth : 20 inches. Average growth : 46 inches. *"- These figures are fairly taken, and the vines have grown in about the same ratio all over the patch. Now I have come to the conclusion that the selected Riparia is worth much more on our soil here than those that came fresh from the woods, doubtless from the bank of some stream where the roots got all the water they required. I believe a large number of these were planted down near Livermore, and it may be that on that soil they have done better than here. If you can hear of any one down there that has faith in the vines of this importation, on whose soil these vines have made gO9d, thrifty, strong growth, I wish you would let me know, for I will sell the 2,000 rooted vines I have on hand very cheap indeed. I do not wish to say that they are not good, but " there are others," and they are so much better that we are going to use these others for our The Riparia Grande Glabre and Glorie de Montpellier made a still heavier growth than the two sorts I have compared, but as they were grown in other soil and under different conditions a comparison would not be strictly fair. Next year I shall have the Napa Riparia and the " Montpellier" growing side by side, so that I can form a better opinion as to their relative merits than I have now. Grafted on old vines, the *' Montpellier " made a growth of 21 feet of cane where an unselected Riparia made a growth of 8 feet and very spindly and poor at that. ?? I send you by express typical vines of "Nebraska" Riparia and of the "Napa," to illustrate their relative growth. You will notice near to root of the " Nebraska " vine a long swelling. This was caused by a borer with which these vines were infested when they arrived. ^1 think, though, that the disinfecting solution used on the cuttings must have killed them all last year, for I have been unable to find any of the borers on the vines this year. Very truly yours, FRANK F. SWETT. LENOIR; HERBEMONT. Lenoir Resistance to phylloxera, 12. Herbemont Resistance to phylloxera, 13. Owingjto the interest in this State in these two hybrids especially the former and the quite extensive plantings already made, as well as those contemplated, a somewhat fuller account of them is given than we otherwise would. The best ampelographers hold that the Lenoir and the Herbemont are hybrids of three species: the resistant species ^Estivalis, the resistant Cinerea, and the non-resistant species Vinifera. The characteristics of the Vinifera are less pronounced in the case of the Lenoir than in the case of the Herbemont, or the Cunningham, which belongs to the same group. The origin of these vines is very uncertain, and much of historical RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 35 interest has been written on the subject. Mr. T. V. Munson, the sava*nt nurseryman, of Denison, Texas, places them in a separate group, which is nothing more nor less than the old " Southern ^Estivalis " group of Engelmann. This Mr. Munson dignifies with the place of a separate species under the name of Vitis Bourquiniana, in honor of G. Bourquin, of Savannah, Ga., who has done good work in studying them. Without wishing to enter into the controversy, I will follow the ideas of the best ampelographers, such as Millardet, Viala, Foe'x, etc., and regard them as hybrids, as I think there is ample proof of this position. The Lenoir and Herbemont have a great affinity for the Vitis Vinifera in grafting, which explains the fact that the production and maturity of the grafted Lenoir and Herbemont are in no way hastened or increased, as is the case when the Vinifera is grafted on the Rupestris or Riparia. Neither of these hybrids grow as readily from cuttings, nor do they graft with the same facility, as the Riparia or Rupestris. It is a mis- take, however, to suppose that they are very poor indeed in this respect, as some say. There is, however, a marked difference in the percentage of cuttings and grafts that take, and the difference shows the superiority of the Rupestris and Riparia. Both of these hybrids stand cold very well. Their resistance (12) is not great, but is sufficient in good soil in cold countries. In warm countries they become, in many cases, so affected by the attacks of the phylloxera that they either succumb, or become so feeble that after some years they do not yield paying crops. In warm climates, then, these two hybrids must have a rich, fertile, cool soil, or they will not pay. There are cases in some of the warmer parts of the vineyards of the world where these have been grafted for twenty-six years, and are still thrifty; but in every case the soil was especially rich, deep, and cool. It has been established, after a quarter of a century of experiment with these two hybrids, that they do not pay as stocks, except in some slightly compact calcareous soils, such as will not grow either Rupestris or Riparia. The Herbemont is especially valueless, either as a stock or a direct producer. The Lenoir is more valuable, especially on compact, cold blue clays, or adobes. As a direct producer the Lenoir is an undoubted failure. Owing to its vigor on rich land and its deep- growing roots it has in this State been found to do better on dry land than the nondescript Riparias. This is not surprising, for a feeble resistant is worthless anyway, and a feeble Riparia on dry soil is utterly valueless. If used as a stock, the grafts that take the best and thrive are those that are made on vines that are several years old six, seven, and more. This is the reverse with the Riparia and Rupestris. The hybrids of Vitis Labrusca and Vitis Riparia furnish us with two that have played an important part in the replanting of the vineyards of the world. These are the Clinton and Vialla. The Clinton has now been abandoned, except in very special cases not necessary to dwell upon ; while the Vialla is still used in certain of the eastern, cold, granitic regions of central France. In hot, and especially in dry countries, it rapidly succumbs to the attacks of phylloxera. Hence it possesses but little interest for California. 36 UNIVERSITY OF CALIFORNIA. SOLONIS. Resistance to phylloxera, 14. This is a hybrid of the Vitis Candicans, Vitis Riparia, and Vitis Rupestris. Mr. T. V. Munson has made a special species of a group of which Solonis is a type. He calls it Vitis Novo Mexicana; but there is little doubt that it is a hybrid. Though this vine has but moderate resistance, it is especially valuable for cold, compact soils that are too moist for any other American vine except the Lenoir. Its special value for California is its quality of growing well in salty or alkali lands where no other resistant would live. In dry or poor soils it will perish from the phylloxera. DOANIANA. This is also a hybrid of the same species as the Solonis, but Mr. Mun- son has classed it as a species calling it Vitis Doaniana. There is no doubt at all but that it is a hybrid. There are several forms of it, as is the case with every group of hybrids. Some interest has been created in this State concerning it, and two of the best forms have been pro- cured from Mr. Munson's valuable nursery in Texas. The two forms thus far imported are the late and early Doaniana. It is valueless as a direct producer, having far too many of the characteristics of the Mus- tang. As a stock, it is vastly inferior to the Solonis, and has been abandoned in other countries. VITIS CALIFORNICA. This species is found in all parts of California, extending partly into Oregon and Arizona. It is one of the most beautiful of all the Ameri- can vines. There are numberless forms of this species, differing widely in their characteristics and habits. Mr. Munson has formed two species out of what the other ampelographers call the Vitis Calif ornica namely, the Vitis Calif ornica, found in the northern part of the State, growing only on the rich, moist banks of streams, and the Vitis Girdiana, found chiefly in the southern part of the State, growing in the dry, sandy soils of that region. This making of two distinct species I think is a mis- take, and I shall regard them as two groups of one species. Many suppose that because all the other American vines resist the phylloxera almost equally well, this is the case with the Vitis Californica. This is an error. The flora of California differ sensi- bly from that of the eastern part of the United States; and the wild grapevine of this State, while having preserved a little of the resist- ing qualities of the Eastern species, evidently came out here in ages when the full resistance to the phylloxera was not wholly developed. Certain it is that the resistance to the phylloxera is very low, but little better than that of the Vitis Vinifera, being but 4 out of a possible 20. It grows so vigorously in its native habitat that many suppose that its resistance is much greater than it really is. In judging of the resistance of a vine, however, one must not be governed by its growth or vigor, but by the nature of the cancerous spots caused by the phylloxera on its roots. As has been shown, a vine may possess a very feeble resistance to phylloxera, and yet maintain its vigor for some time by reason of its RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 37 special adaptation to the soil and climate. This is the case with the Californica. There is but little doubt that along the rich, moist creek- beds of its native home it may be able to withstand the phylloxera for an indefinite time; but it is very certain that once it is removed to drier or different and more unfavorable conditions, it will speedily perish from the attacks of the insect. This has been the case wherever it has been tried under unfavorable conditions. It grafts readily and grows well from cuttings, and is most vigorous. Undoubtedly, if the Califor- nica is to be depended upon, vigorous specimens from the wild vines growing in dry places should be looked for, as dryness is one of the chief characteristics of our soils. In selecting cuttings for planting, the vineyardist should carefully study the nature of the special soil of the vineyard, and try to select wild vines growing on as nearly similar soils as possible. As is the case with all the other American species, there are hundreds of varieties of the Vitis Californica, and most of them will be found to be worthless. So, in selecting, look for vigor, thickness of cane, and resist- ance to drought. The Californica should evidently not be used as. a stock when good Riparia or Rupestris can be obtained. VITIS ARIZONICA. This is a species that inhabits Arizona and New Mexico. It possesses quite a good resisting power 16 out of a possible 20; grows readily from cuttings, and grafts well. It has not been well tried in California, but time may show that a readily adaptable stock can be obtained from it. It is certain that it is inferior as a stock to the Riparia and Rupestris, and where even the Arizonica will grow, the Riparia or Rupestris will do well; so that for the present, experimentation with it should be limited. GRAFTING. The grafting of the vine is an operation that has come down to us from the earliest times. In fact, to-day our processes differ but little from those described so minutely by the Romans. It is especially since American vines came into use as stocks that resist the phylloxera, that the grafting of the grapevine has become common. Formerly it was used merely as a rapid way of changing the varieties in a vineyard; while to-day, on the contrary, all vines must be grafted, either before planting, or after the vineyard has been planted out. It was in 1869 that Messrs. Laliman and Gaston Basile called atten- tion to the importance of this operation in the reconstitution of the phylloxera-ravaged vineyards of the Old World. To-day it is an opera- tion which each and every vine-grower is forced to practice. In Cali- fornia but little attention has been paid to this most important operation; and if one will but take the trouble to examine some of the grafted vineyards of the State, he will find some specimens of the poorest handiwork imaginable. In fact, some of the reported failures of the grafted vineyards are traceable to this cause. To those who are expert grafters (and there are many such), my excuses for dwelling somewhat at length on this subject are offered in advance. I do so, however, in order to answer many questions from many who are not experts, but who have the desire to be. 38 UNIVERSITY OF CALIFORNIA. ANATOMY AND PHYSIOLOGY OF THE GRAFT. (a) The Tissue of the Joint. On the lower section of a graft pruned to one or two eyes/and placed in appropriate conditions as to heat and moisture, there will appear small protuberances of tissue, called callus, on the inner edges or lips of the cut or section. (Just as at the base of all cuttings. See Fig. 1.) These protuberances are but gatherings of cicatricial tissue. They are all the more numerous and developed as they are nearer the base of the section; and on an obliquely-cut graft or scion (as is cut for an " English graft," see Figs. 2, 3, and 4), it is at the lower extremity of the wedge that they first appear. They are destined to cover the wound made by the section, and to shelter it from exterior influ- ences, such as those resulting from rots, etc., by an envelope of cork with which the living parts of the cane (the generating layer, liber, bark, etc.) are covered. The juxtaposition of a corresponding section (that of the subject or stock) alters the destination of the callus. The wood itself has no influence whatever in the formation of the cicatricial tissue; it re- mains just the same as it was at the moment of grafting. Hence the better joints are made without too great an amount of wood being inclosed; the wood being useful only for stiffness. Too much or too little wood is equally bad. A certain amount is necessary to give bark enough to form callus. The principal part in the formation of the callus devolves on the cambium or generating layer. The mechanism of this forma- tion is somewhat as follows: The cells of the scion that are in immediate contact at the surface of the section, and which belong to the regions constituting the generating layer or inner bark, become more active;, they subdivide, multiply, and become prolonged in a direction perpen- dicular (or nearly so) to the surface of the cut. The cells of the soft bast become transformed into still softer cells, the walls of which are thin and non-lignified; they keep on subdividing and multiplying, and, united to those that are the tissues of those resulting from the activity of> the cambium layer, they constitute the small bumps of the cicatricial tissue. Soon the exterior cells, that is to say the oldest, become suberi- fied (or changed into cork), and in one or two layers they form the pro- tecting envelope of cork, more or less resistant, which incloses completely each protuberance, and which becomes attached, sometimes, to the cork envelope of the cane. On the superior section of the canes the same phenomena occur, but they seem to be less distinct and take place much later than is the case with those on the graft itself. This is because the cane (as is the case with the entire vine) has no tendency whatever to cover or protect the wounds made on its superior extremities. The terminal section of the cane never covers itself with callus. The surface of the cut dries out to a varying distance, its channels become clogged with gum, etc., but never close up with living tissue. Every one has noticed that cuttings stratified in cool sand or soil form callus, especially at the lower end of the cane, and only in most exceptional cases is any callus found on the upper end of the cane, and even then this is because of the juxtaposition of another section of cane. If a longitudinal section on a cane is made, the cicatricial tissue forms at first on the lateral edges, and scarcely at all on the transverse section. Finally, the cicatricial tissue forms in greater abundance near an eye or bud than near the middle of the internode. It is the pro- tuberances of the cicatricial tissue on the graft and stock placed in con- RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 39 tact with one another, that form the joint. The younger they are at the moment they join (that is to say, the less their cells are suberified), the better will be the joint. It will be seen from this that the various regions of the bark should be placed as close together as possible. The cells which are derived directly from the activity of the generating layer become joined; one of their layers is transformed, and becomes generat- ing tissue, and unites with the generating tissue of the stock. From this moment the grafted stock grows normally till the joint is com- pleted from the top to the bottom of the wound, and performs its functions as though no wound had been made, and forms wood on the inside and bast on the outside. If the bumps of callus be put in contact when they are old, the joint is far less perfect, and although a joint will form, it will be a very poor one. The tissues are derived from the activity of the new generating layer, and differentiate so as to continue either the libroligneous bundles or the medular rays, etc., corresponding to the graft and the stock. There will, however, be numerous anastomoses formed, thus enabling the circulation to take place almost as though there had been no inter- ruption made in the tissue made by the graft. Such is very roughly the mechanism of the joining of the graft with the stock. From the foregoing we have supposed that the subject or stock was a shoot or part of a branch more or less aged. One could, however, have equally well taken a root or portion of one as the stock. The large roots of the vine have (save a few bands of bast fibers) sensibly the same structure as the cane from one to three years of age. In such a case the joint is produced in the same manner as above described. The cicatricial tissue does not form equally well with all varieties of the vine, whether used as a graft or as the stock. This is observed in the case of a large number of other plants. Some will scarcely form a callus at all, while others form it with the greatest facility. In the case of the vine, the divers varieties have this peculiarity in a very marked degree. Thus we note abundant callus, hence easy grafting, in the case of the Berlandieri (which, however, will not grow from cutting), the Vitis Cinerea, Rupestris St. Georges, Vialla, Cabernet Sauvignon; and a very poor grafting power in the case of the Solonis, Folle Blanche, etc. But independently of the nature of each variety, the formation of tissue is profoundly modified by other exterior agencies. According to Prof. Millardet, callus is most rapidly formed at a temperature of 68 F. Some, however, maintain that a temperature from 87 to 95 F. is more favorable, but beyond this the graft will suffer. Below 60 F. the formation of callus is very slow indeed. What is essential is that the temperature should be sufficiently great, but always regular. The greatest amount of callus is found in the case of grafts buried in light, warm soils at a depth sufficient to cause the variations of heat to be as light as may be. The degree of humidity of the soil exerts a very great influence on the successful joining of the graft to the stock. If a cutting or a grafted cane be plunged into water so as to cover the lower parts of the cane, no cicatricial tissue whatever will form.^ Grafts covered with fine sand, kept constantly wet by irrigation, may put out young shoots, but will never form a joint. This is frequently noted in the case of stratified 40 UNIVERSITY OF CALIFORNIA. grafts where too much watering has been indulged in. In sand that is kept slightly moist, on the contrary, the best results are found. On the other hand, aeration assists greatly in the formation of callus. Growing cells respire more than is ordinary for older ones, and hence they require a medium that is especially well supplied with oxygen. We note, therefore, that grafts that are deeply buried in very compact soils will scarcely callus at all. (b) Effects of Grafting; Affinity. It is a general rule that there is an enfeeblement of the graft, except in the case where the graft and the stock are of the same variety; and it is also a fact that this is accom- panied with an excessive fructification of the grafted vine, especially where the enfeeblement is most marked. Together with the excessive fructification is noted a production of a greater number of bunches which are larger than the normal; also, larger and better nourished berries of earlier maturity and a greater richness in sugar. Another important item in this case is the fact that there is always less " coulure." On the other hand, with the enfeeblement of the vine by grafting, while the crop is benefited, there is noted an increased susceptibility to the phylloxera, as well as swellings of more or less size at the joint of the graft with the stock. The effects of the graft are similar to that of the annular incision so much practiced in hothouse grape culture to give size and sweetness to the grape. At the same time, while the results are similar, there is quite a difference in the causes. Beyond a mere interruption of sap in the case of the annular incision, the similarity ceases. In the one case it is a temporary wound, causing an interruption of the reflux of the sap; while in the other there is a lack of harmony in the functions of the various parts of the plant, which brings about the same effect as the annular incision. There is a difference in vigor only when the variety of the graft and of the stock differ, otherwise it is but a wound that will rapidly heal up and leave the vine as it was before. The greater the difference in variety, the greater will be the difference in effects. A graft of the Vitis Vinifera on the group of the American species called Muscadina, may grow for a time, but the graft is so badly nourished that it soon perishes. The same is true in the case of grafts on the Ampelopsis, Cissus, etc. On the Vitis Riparia, the physiological functions of which are quite different from those of the Vitis Vinifera, the difference in vigor is quite marked. They are less in the cases of the other resistant stocks which approach more closely the Viniferas. In the case of the Franco-Amer- ican hybrids these differences are still less. The chemical composition of the Franco- American hybrids is the same in the case of grafted vines and non-grafted ones, which furnishes us with an indirect proof of the greater affinity of the Franco- American hybrid for the Vitis Vinifera than in the case of the American stocks, which do show a chemical difference in composition between the grafted and the non-grafted vines, as well as greatly diminished vigor. Allow- ance being made for resistance to the phylloxera, it will be seen that there is greater affinity between the Franco- American hybrids than between the pure species. But it is to be noted that the various European vari- eties do not always behave alike on the same stock. The Cinsaut does badly on the Riparia, while the Carignan does better than the Aramon on theLenoir and Riparia. The Clairette is one of the varieties of the Vitis UNIVERSITY OF RESIST A Ny^JEgp^R SELECTION, ADAPTATION, ETC. 41 Vinifera that suffers the least from grafting. The Alicante Bouschet, like the Alicante, from which it is derived, grows old and feeble very rapidly, while the Petit Bouschet is much superior to it in this respect. The Grenache has but a medium affinity for the resistant stocks. The Ter- rets (Terret noir, Terret gris, Terret bouschet) are not very vigorous when grafted. The Morrastel suffers but little, and the Ugni blanc, or St. Emillion, is quite vigorous on non-calcareous soils, where it is exceedingly liable to chlorose when grafted, as is also the case with the Folle blanche. Muscats behave very well after grafting, as do the Picquepoules, Colombeau, etc. The Cabernet Sauvignon maintains its original vigor, as does the Cabernet Franc, Charmenere, Verdot, and St. Macaire. The Malbec is more sensitive to the chlorose after grafting than are the Cabernets, while the Merlot suffers but little. The Sauvignon and Muscadelle do well on resistant stock, while the Semillon leaves much to be desired. The Pinots are more sensitive to the chlorose on dry or calcareous soils than are the Gamays. The Gamay noir, ungrafted, is not a vigorous vine, and grafted it will never be sufficiently vigorous; the white Gamay is more satisfactory hi this respect. The same may be said of the Ploussard. The Syrah takes on great development when grafted, and may be said to be one of the JEuropean varieties that does exceptionally well on resistant stocks. The same may be said of the Mondeuse, if we except cases where the subsoil is exceedingly calcareous. The Etraire, Persan, Durif, Corbeau, and Roussanne do well grafted, while the Marsanne is less vigorous. SYSTEMS OF GRAFTING. It will not be possible in this brief discussion to describe all the various systems of grafting, as practiced in all parts of the world. It will be merely an attempt to give the essential points of the two most usual and most simple and practical that are in use in the majority of cases with practical vine-growers. English Graft. In practicing the sections for this graft, the stock and scion should be cut in the same manner (Figs. 2, 3, and 4). They should have the same surface and the same contour, and, therefore, be of the same size. The stock, be it a rooted vine or a cutting, is cut sloping (or beveled) at an angle of from 14 to 17 degrees with the axis of the cane or trunk. The cut is made as near the eye as is possible; for, as we have shown, it is at this point that tissues which form the joint develop with the greatest rapidity. The length of the cut is proportional to the diameter of the cane or trunk. At an angle of from 14 to 17 degrees it is generally sufficiently long to afford firmness and stability. Grafts and stocks are generally cut by hand, though there are many " grafting machines " in use. I think that the experience of the world has been that, in the end, it is economy to have the cutting done by hand; though at first a clumsy workman may do better with a "machine." But none but clever hands should ever be allowed to attempt to graft, and then they should have a certain time allowed them to " get their hands in." Experience has shown that it requires an ordinary work- man as much time to learn how to properly use a " grafting machine " as it does a good, intelligent man to learn to hand-cut all the grafts and master the technique; while there is room for constant improve- 42 UNIVERSITY OF CALIFORNIA. i> ment, which is impossible in the case of machine grafting. The sections should be made with a single stroke of the knife, which must be very sharp, otherwise there will be so many irregularities that a good joint, depending as it does on close contact, will be impossible. The slanting section being made with one clean cut of the knife, another cut is made, parallel with the fibers of the wood of the cane and stock (Fig. 4), to a depth of at least one fourth of an inch. In withdrawing the blade of the knife, care should be taken to give it a slight rotary motion so as to press the lips of the cut apart, and thus facilitate the insertion of the corresponding tongue of the other part to be joined. The object of this parallel cut is twofold: to insure firmness in holding the two parts together until the callus has formed and new wood devel- oped at the joint; but most especially is it for the purpose of increasing the surface where callus can form and thus enhance the chances of getting a good joint. The exact position of the parallel cuts is of little importance, and should not be too seriously considered. So far as regards the life of the cane, the pith is of no importance at all, and, hence, can bfc disregarded in the consideration of the problem. Of so little importance is the pith that it can be removed without injury to the cane. The only importance of the position of the parallel cuts rests in the fact that the beginning and the end of the cut must be at equal dis- tances from the center of the cane, in order that the cuts in the graft and the stock can be in exact juxtaposition. It will be seen from this, that the nearer the cuts are made to the center of the section, the shallower they should be, and also the farther they are from the center, the deeper they should be. If these directions be not carefully followed the adjusting of the corresponding parts of the graft and stock will be defective; the two short sections will not be able to cover each other, and the excessively long sections will be lacking in solidity. The graft or scion, whether it be of one or two eyes, is cut exactly as is the case with the stock. The accompanying figures are given to illustrate these points (Figs. 2 and 4). The English graft, or whip graft, is one that gives the best joints; the scion and the stock being cut so as to correspond exactly, gives greater surface for the formation of callus, which forms on all parts of the cut surface of the bark so well that the healing takes place on all parts of the wound. This causes the sap to circulate almost as though there had been no interruption whatever. On the other hand, while this system gives by far the best joints, it gives, perhaps, fewer cases of success with the unskillful workman; but if well done the difference is so slight, com- paratively, as to make it the favorite system of all those who have carefully experimented with it. It is to-day the most common in all the large vineyards, and especially in the nurseries of France, where grafting has been so extensively and thoroughly tested. Perhaps one of the reasons why this system is not highly esteemed in this State is because of the difficulty of getting cuttings of resistant vines that are large enough to be grafted before planting. Owing to the very poor varieties of the resistant vines that have thus far prevailed here, together with the method of planting the cuttings in place and waiting several years before they were large enough to be grafted, this system has not been given a fair trial. With the importation of varieties of resistants which give canes fully as large as any of the Viniferas, things will change, and it will be found, as has been the case elsewhere, KESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 43 "that " English " grafting is the best of them all. By grafting the cuttings, and then planting the grafted cutting in nursery, much of the expense connected with the planting of a vineyard on resistant roots will be obviated. It would certainly seem that if a people who have made a success of 2,500,000,000 grafts have adopted this system as their favorite, it is worth our consideration. Cleft Graft. In this case the stock is always larger than the graft, or scion, the section being generally made with a shears or saw, as the size of the trunk warrants. This is the most common system in California where but little nursery grafting is practiced; partly from the necessities of the case, arising from the fact that it has been deemed necessary to graft only older vines, partly from the fact that our resistant stock is of such poor and feeble varieties that it is difficult to obtain scions that are anywhere near the same size as the stock. This difficulty being about to become a thing of the past, vineyardists may look forward to the time when the cleft graft will be practiced only in special cases, and " English" grafted cuttings will be planted in nursery. The accompanying figures are given to illustrate what is meant by cleft grafting (Figs. 1 to 9). This system having been so well described and so generally known in this State, it is not necessary to dwell on details, remarking in passing that with the illustrations and the general principles already given, even a novice can readily learn it rapidly. It is to be observed from the general principles set forth in the preceding part of the discussion that there should be as complete a juxtaposition of the generating layers of the two barks as may be. Also, that while moisture, if in excess, is bad for grafts in the process of " taking," on the other hand, too great dryness is, if possible, worse. It is probable that in California more damage is done from drought than from excessive wetness at the graft. I have seen many grafters cut the stock, as well as the scions, and leave them exposed to the action of the sun and wind for many hours before covering them or joining them together. Not only this, but in a naturally dry soil they either cover the graft too little, or cover it with perfectly dry, hot earth. As has already been said, air is necessary to the formation of callus, but so is moisture, neither being in excess. This means that the grafts must be covered not only with loose, but moist (not wet) soil. It is because of this that compact wet or dry adobes or clays are found to be very bad for successful grafting in nurseries, partly on account of lack of aera- tion, partly on account of the natural tendency of such soils to " pack " and "bake," and partly on account of the almost impossibility of retaining sufficient moisture in them. Hence it is that for nurseries we should always select a very sandy, moist soil, in default of which it will be found that it will pay to haul sand to put around the joint of the graft and the stock. This is frequently done with the greatest benefit. Moderate irrigation is advisable in almost all the soils of California when they are used for nurseries. As a general rule, the drier and more refractory the soil, the deeper should be the burying of the graft, it being understood that the graft should be ordinarily about an inch below the natural level of the land. In cases where there is a great excess of vigor of the scion over the stock, the depth of the graft should be greater, though deep grafting necessitates the annual cutting away of the suckers from the graft above the stock. FIG. 4. FIG. 7. FIG. 8. FIG. 9. Fig. 1. Formation of callus on a scion cut for a cleft-graft. Fig. 2. Stock and scion ready for whip-graft for cuttings and small vines. Fig. 3. Manner of cutting scion. Fig. 4. Respective positions of parallel cuts in scion and stock of cleft-graft. Figs. 5 and 6. Ordinary cleft-graft on old vine ; the dotted lines showing the manner of banking the grafted vine in ordinary moist soils. Fig. 7. The scion cut for cleft-graft. Fig. 8. Manner of using raffia on a cutting whip-graft. Fig. 9. Manner of using raffia when lead strips are used. RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 45 Ligatures. In the case of crown or cleft grafts (on vines of more than one year, selected varieties) ligatures are seldom necessary. The only object of binding the graft to the stock is to give solidity, which is furnished by the natural stiffness of a large stock such are usually cleft-grafted. In the case of grafting a vine with a thick trunk, the scion will be held in place naturally. The practice of daubing clay or mud around a graft cannot be too strongly condemned, for it pre- vents respiration which has been shown to be especially necessary for the formation of callus and it furnishes no solidity whatever. The smaller the diameter of the stock the more the necessity of liga- tures becomes, for there is not sufficient natural stiffness to maintain the scion in place. The use of cotton "grafting twine" (such as is commonly used in nurseries for grafting trees and shrubs above ground) has been abandoned by those who have tried it on grafted vines. The reason is that it has no elasticity, and will not decay in time to permit the free development of the stock, but has to be cut off about June or July. The use of patent elastic bands has also been abandoned, because of too great expense; although they are excellent in aiding good joining. At one time split corks bound with wire were highly thought of and used to a considerable extent; but owing to the expense of the raw material, as well as the necessity for removing them in July or August, they were abandoned. As in the case of the rubber bands, they accom- plish the object most perfectly, but are too expensive. The best and cheapest material now used is raffia, which serves the purpose of holding the two parts of the graft together, and while it is cheap, it seldom requires cutting off, as in ordinary moist soils it will rot off. When first used it is very strong, and will stand all the strain necessary to bind the two parts of the graft firmly together. Owing to the rapidity with which it will rot in very moist, warm soils, and the danger of resulting infection of the joint with the micro-organisms of decay, it is frequently dipped in a solution of from 1 to 3 grams of sulphate of copper to the quart of water. While this certainly accom- plishes its object of preventing infection, it very materially retards the process of callusing. This is obviated, in part, by washing the dipped or soaked raffia in running water, which removes the copper sulphate or bluestone. When " bluestoned " raffia is used, some nurseries use tin or lead strips, around which they tie the ligature of raffia. This is too expensive an operation, however, for very general use, aside from the bad effects of the tin or lead salts that form and hinder the forma- tion of callus. Almost every grafter has his own favorite method of tying the knot. This is immaterial, so long as the raffia is not too loosely or closely wound on so as not to afford support or to touch and suffocate. Too close winding prevents free access of air, which has been shown to be necessary for the proper formation of callus. We give an illustration of how raffia is usually tied, in Fig. 8 and Fig. 9. Time for Grafting. Grafting can be done at almost any time between February and May, according to the season. Some prefer late, while others hold to early grafting. I think that the most experienced and successful grafters prefer the earlier method. The danger from late 46 UNIVERSITY OF CALIFORNIA. grafting is that the soil covering the grafted vine or cutting will dry out, in which case failure is assured, while too early grafting will incur the risk of rotting. Some suppose that the scion is "drowned," if grafting is done when the sap is beginning to flow so that the vine " bleeds." This is an error; perhaps some of the most successful grafts are made early. While there is little to be feared from the excess of sap in the vine at grafting, there is much to fear from rains at this time. It is certainly better to take chances from moisture rather than from drought either extreme being bad for the success of the operation. It is on account of danger arising from excess of drought or moisture that special care should be given to the "banking" or covering of the grafted vine or cutting. Covering too deeply is almost as bad as insufficient covering. In very moist soils and climates especial care should be given not to bury^ too deeply while when there is a-ny ten- dency to dry out, deep burying is to be advised. There is a limit, of course, even in the driest of climates; if a graft be too deeply buried, the shoots or growth experience very great difficulty in forcing their way to the air and making proper growth. It is for this reason that scions of two buds are preferable to those of one. In the former case the top bud can grow freely, and it is seldom that the second eye, the nearest stock, will develop at all. In very dry, loose soils -it is well, per- haps, to use even three eyes or buds. Cutting Off of Roots. It is necessary about July or August, according to locality, to carefully cut away the roots that may have started on the scion. By this time the joint is pretty well formed. The roots that grow on the scion are not, after all, any very great obstacle to the " taking" of the graft, and if their development is, as is well known, inverse to the production of callus, they are in most cases the conse- quence of a slow joining. Their suppression in July or August is too late to materially affect the joining of the scion to the stock, but they must be none the less carefully removed. This is because when the scion is partly nourished by its own roots, and partly by those of the stock, neither the one nor the other plays its proper part in the vegeta- tion of the plant; and as the non-resistant scion is partly interrupted in its communication with the roots of the stock, it tends to draw more freely from its own roots, with which it has uninterrupted communica- tion, than from the stock. The result is that most all the root develop- ment takes place on the non-resistant roots and the resistant stock becomes unduly enfeebled, so that when the phylloxera attacks the roots of the scion, the resistant roots are unable to nourish the large develop- ment of foliage. This, deprived of its nourishment, becomes sickly, and in many cases causes the whole vine to perish. Of course all suckers should be removed as soon as they make their appearance. Care to be Given the Grafted Vines. In very cold regions, where there is damage from extreme cold in winter, the grafted vines should be " banked up " at the beginning of winter, and early in spring the soil should be plowed away from them. The stock is frequently more feeble than the scion, especially on the Riparia and Solonis; and hence is exposed to the danger of break- ing off from wind, etc. The rupture seldom takes place just at the joint itself, but generally (in the case of a well-grafted vine) just a little below the joint. It is well, then, to " stake" the grafts for a few years. RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 47 Pinching back, as is sometimes deemed necessary, is a useless opera- tion, though it is a harmless one. Great care should be taken to sulphur well the young growth on the grafted vine against oidium (powdery mildew), and treat with Bordeaux mixture against peronospora (downy mildew) and black rot. Sometimes rooted vines from the nursery are planted in autumn, to be grafted the following spring, or in May. In this case there is really a better chance of successful grafting than in the case the cutting has been planted an entire year or more previously that is, if the rooted vine is in healthy condition. Choice and Preservation of Scions. In choosing the scions, one should be very careful to take canes only from the most vigorous and fruitful vines in the vineyard. It pays, and pays well, to go over the vineyard, just before the vintage, and mark with paint or a cloth the vines that are especially heavy bearers, and take scions from these only. Careful experiments on this subject have been made for a great many years, and it has been established beyond dispute that, either for cuttings or grafts, it is more profitable to select the cuttings or grafts from those vines that possess in the greatest degree the qualities desired in the vineyard that one is planting. Scions for early grafting (February) can be taken directly from the vines, while those for later grafting should be cut off before the first movement of the sap, and carefully preserved in a cold room, exposed to the north, and they should be buried in almost dry sand. They should be completely covered with sand. For, as has been said, the stock calluses slowly, and it is essential that it be further advanced than the scion. CUTTING GRAFTING. Canes of the American resistants destined to be " cutting grafted " should be i inch in diameter at the " small end." They are cut 10 to 11 inches in length. The lower section is made below, and as near as possible to the eye (Fig. 2). This is on account of the facility with which roots form near the eyes. The upper section is made 1 to 1-J inches above the upper eye. It is well known that the most numerous, as well as the most vigorous, roots grow from the eye itself, rather than nearer the middle of the internode. This is especially necessary for all vines that grow with difficulty from cuttings. One can use the entire cane of an American resistant vine as a "cutting stock," with the sole proviso that it has a sufficiently great diameter to enable it to hold the scion in place. Theoretically it can be done with almost any sized cane, but practically it has been found that about i inch is the least diameter of a "stock cutting" (unless in the hands of a most experienced grafter). With selected varieties, especially if these have been grown for some years on rich, moist land, or grafted on old, vigorous stocks, the canes are almost sufficiently large. Here it might be well to note that those who are in haste to " get wood " from a few cuttings, should cut the cuttings into short scions and at once graft on some vigorous vine (resistant or non-resistant, it makes no difference), and they can get abundant wood the same year. One cannot depend on getting scions or cuttings, large enough for " cutting grafts," from any resistant the first year, if planted out in place or in nursery. This was well illustrated in 1896 at the place of John Swett, 48 UNIVERSITY OF CALIFORNIA. of Martinez, Contra Costa County. The University imported a number of selected resistants, and asked Mr. Swett to make some comparative experiments with the selected re-imported resistants and some non- descript varieties of the same species he had from a Nebraska importation. He grafted the two kinds side by side on the same variety of vine of the same age, and found that while the selected varieties gave, in one hundred and twenty days, twenty-one foot canes over \ inch in diameter, the other gave about one fourth the growth and size. The balance of the cuttings were planted at various points in the State, and few of the canes were large enough for cutting grafting; though, of course, they were large enough (though there were few of them) for use as cuttings used in the old-fashioned way. Hence, to all those who desire to propagate improved varieties, in order to get what cuttings they can the first year, we would recommend that they graft these cuttings on old, vigorous vines. It might be well also to advise here, that much more available wood can be made if care is taken, during the early growth of the vine, to pinch off all secondary growth, and confine the energies of the vine to forcing the main canes. This is easily and cheaply done, and pays handsomely on the few hours' time expended in this work. After the first pressing needs in supplying cuttings have been satisfied, a few can be planted on some rich, moist land, and these can be kept for all time for propagating purposes. Vines thus preserved are called " mother-vines." Many suppose that it is necessary to scrape, or slash, the bark of a grapevine in order to facilitate the throwing-out of roots. This is only partly true. It is never necessary, but in the case of certain vines that root with difficulty, such as the Lenoir, Herbemont, Solonis, etc., it may do some good, in facilitating the penetration of water into the tissue of the cane, to replace that which has been lost by evaporation from that part above ground. In the case of cuttings that have been slightly dried out, this scarring or scratching is sometimes profitable. The most important thing in the preparation of a "cutting-stock" is the removal of all the buds or eyes from the stock, even the one at the very base of the cane. It will not suffice to pinch these off with the finger-nail. They should be carefully cut away with a knife, so that they cannot possibly grow out again. Mere pinching off of the bud causes four or five others to grow out around the one suppressed. These live at the expense of the whole vine, and greatly hinder the formation of a proper joint. This precaution is especially necessary in the case of the Rupestris. This species is accused of "taking" very poorly from cutting-grafts. It would seem, however, that the reported failures in this case are due solely to the fact that the buds were improperly suppressed. In the case of the Vialla or Riparia one can merely pinch them off; but in the case of the Rupestris, etc., they must be cut off with a very small portion of the bark, leaving a clearly-cut shield-shaped cut. If Rupestris cutting-stocks are thus cut they "take" better than almost any other. Hence, we may advise that in all cases of cutting grafting, the buds of the stock should be carefully removed. Prof. Viala tells us of 45,000 grafted Rupestris cuttings that he planted, and made 80% grow well. Mr. H. Lefranc, of San Jose, last year imported a number of grafted cuttings of Rupeptris from France, and made 70% grow, and these had been treated in the same way. NON-SELECTED. SELECTED. Photograph of non-selected and selected vines of the same age growing side by side in the vineyard of John Swett & Son, Martinez, Cal. 49 The scion should have one or two buds or eyes. One is sufficient, if the nursery in which they are planted is in a very moist, friable, rich soil, in which case the joining may be very near the surface. But when there is the slightest chance of drying out, there should be at least two eyes, in which case the junction may be buried much deeper in dry soils. As has been already stated, care should be taken not to bury the joint too deeply; for not only is there danger of smothering the graft from lack of sufficient air, but the shoots or growth will be imperfect. The whole question, then, is one of the exercise of common sense. One must be capable of judging of the mean between too dry and too wet, too shallow and too deep. In all these operations one can but indicate the general principles, and the rest must be left to the common sense of the operator. The basis of all viticulture is, of course, common sense. Grafted cuttings which are made in April or before, or have to be kept for some time, are always tied with raffia which has been dipped in bluestone, as before described; or the tin or lead bands and the blue- stone raffia may be used. After April, the simple, undipped raffia is used. In any case, however, it must be remembered that the bands of raffia should not touch each other, but a space should be left between, so that there may be free access of air to aid in the formation of callus. Heeling In. Grafted cuttings thus made are either planted immedi- ately (in April), or kept until a more favorable time. In the latter case they are tied in bundles of ten or twenty, and buried in cool sand, out of doors, but protected from the rain, frost, and sun. While they should not be buried so deeply as to prevent aeration, they should be covered sufficiently to avoid great variations of temperature, and drying out. In other words, they should be kept as were scions under the old system. This is all exceedingly simple, requiring only a little attention. Grafted cuttings in a moist, sandy place take, little by little, the moisture they require; the temperature is then more constant and greater, especially if they are so placed as to be in the sunshine part of the day, in which case the joining tissue will frequently form before they are ready to be planted out in nursery. What must be avoided is an excess of moisture, which will, it is true, hasten the appearance of roots, but which is very unfavorable to the formation of cicatricial tissue necessary for the formation of the joint. The sand in which the grafted cuttings are preserved should not contain more than from 5% to 10% of water. When all these precautions have been taken, the joint is almost com- plete by the end of a month, the scion commencing to develop and the roots to grow. It is at this moment that the cuttings should be planted in nursery. It is not deemed advisable to keep the cuttings in moss, for many reasons needless to be enlarged upon at this time. 4 RV 50 UNIVERSITY OF CALIFORNIA. NURSERIES. Choice and Preparation of the Soil. Strictly speaking, any soil can serve as a nursery, but in practice it has been found that those most favorable are moist, sandy, or gravelly alluvials, rich in humus and all the plant-food required for the normal development of the vine. Soils that are compact naturally, or which tend to pack too much, such as clay or adobe, are to be avoided, as are all soils that do not retain their moisture well, or those that are not within the reach of irrigation water. There also may be mentioned among the doubtful soils, those that tend to bake or crust over on the surface. In case of a soil not naturally rich in plant-food, the nursery should be previously well fertilized, either with chemical fertilizers or stable manure. It is not economical to plant a nursery in an exhausted soil, or one that is naturally not very fertile. The slight expense of enriching the small nursery plot pays handsomely in the end. In all cases the land should be very carefully prepared beforehand by very deep and frequent plowing and cultivating. It has been shown that American vines insist on deep plowing previous to being planted out in vineyard form; but in nursery this is especially urgent. I have seen in this State some nursery soils that have been selected at the last moment when the soil was dry, given but a shallow plowing and the vines planted at once. This cannot be too strongly condemned. Some recorded cases show that nurseries have been planted under the shade of oak, eucalyptus, etc., trees " for the shade." This is to be deplored, for sunlight is very favorable for the rooting, as well as the callusing of cuttings; trees of all kinds so sap the soil of moisture and plant-food that a young struggling vine cannot be expected to grow at all. Planting. Grafted (as well as ungrafted) vines should be planted in April or the beginning of May, or even earlier, according to the locality and season. The nursery rows should be about 2-J feet apart more or less according to the kind of plows and cultivators used; the workmen should never be cramped by too narrow rows, and in large nurseries the rows should be grouped in " blocks " for convenience. The ditches can be made with a plow and deepened with a shovel. It is well to even off the surface of the bank on which the cuttings are to rest, with a hoe or rake. The cuttings should be placed on this sloping bank so that there is good, loose soil below and behind; and each cutting should be pressed in so that no useless air-spaces will be allowed to exist and cause drying out. The cuttings should, in good, well-prepared soils, be so placed that the joint will be an inch below the natural level of the soil. Then the most friable top-soil, carefully pulverized, should be carefully put on next to the cuttings and the ditch filled ; the first earth being packed so as to avoid " air-holes." It is of course understood that no cutting should be planted when the soil is wet. In cases of an adobe soil it is best to barely cover the entire length of the cutting with a layer of sand, and then add the top-soil to this, In banking the cuttings after the natural level has been reached, it is the custom to cover the top of the entire cutting at first with a 3 'S . O RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 51 layer of earth about half an inch deep. This will soon " settle " and expose a very small part of the top of the cutting, barely exposing the top eye or bud, and thus allowing free room fo'r the top growth. Too deep burying is as bad as too great exposure of the top, especially in our dry climate. Care should be taken to have thejcuttings of equal length, and the ditch of a uniform depth, so as to have the tops at the same level. If it be deemed necessary to fertilize the soil at the moment of planting, care should be taken not to put the fertilizer in immediate contact with the cutting, but always with an inch or so of soil between. If fertiliza- tion is practiced, it should be done previously. In forming a nursery, one may have all the cuttings slope in the same direction, or he may have them sloping away from each other on either side of a bank, by making furrows and turning the soil toward each other, with a space of a foot between the tops of the cuttings. The farther the cuttings are apart, the better they will do; as a rule they are never put closer than 4 inches. All depends, however, upon whether the cuttings are grafted before planting, or whether they are to be grafted in the nursery, and especially whether they are to remain more than a year in nursery. In the latter case, they should be placed farther apart than in the former. A number of figures are given illustrating the manner of planting a nursery. From these will be seen the manner of proceeding better than one can explain. (See Fig. 10.) Care of a Nursery. Great care should be given to a young nursery, in order to get the maximum from the money invested. One should, in the beginning, see that no crust is formed or " baking " takes place. After this, the weeds should be kept down, especially at first. In order to avoid baking after a rain, a garden rake in the hands of a careful man is valuable, the danger being in the knocking off of the young shoots in case of carelessness. If, in a dry region, it becomes necessary to irrigate while the cuttings are "banked" (that is, before the joining is complete), care should be taken that the water does not come in immediate contact with the joining of the stock and scion. The exca- vations, or ditches, below the surface, made by the banking, will enable one to avoid this difficulty. Transplanting. The vine resulting from a grafted cutting is very apt at the end of the first growth to have much of its wood badly matured. It is then necessary, in regions where there is fear of a very cold winter, to protect the trunk of the young vine by banking the earth around the main part of it. This can be done with an ordinary plow. Some prefer to dig up the young vines in November and bury them in piles, deeply covered with earth. These beds of rooted vines are usually made either near the nursery itself or at any convenient place. In digging out the vines the greatest attention should be given to determining the question, "Is there a good joint?" In case of doubt, it is advisable to reject the vine. After a very few trials one can easily tell whether the joint is perfect or not. Taking the vine in both hands, one above and the other below the graft, and straining it, and at the same time giving careful examination for defective spots, will speedily determine the value of the vine. It is of far greater importance to the 52 UNIVERSITY OF CALIFORNIA. vine-grower to plant only perfectly grafted vines than many seem to sup- pose, if we may judge from the specimens we have seen in this State. It is not the cost of the poorly-grafted and rejected vine that should be considered. This is insignificant when compared with the great amount of time and actual cash lost in planting and cultivating the land around the doubtful vine for from one to six years before it is dis- covered that the graft is so defective that the whole vine must be dug out or regrafted. It will be noted in the grafted vineyards in this State that very frequently a badly-joined vine may be able to support the first few years of growth so well that one would never suppose that there was a defect in the graft, especially if the roots be neglected on the scion, as is frequently the case. About the time the phylloxera begins to attack the neglected roots on the non-resistant scion, and the vine comes into full bearing and requires more support than ever, is the time when the vine-grower begins to neglect cultivation a little, on the plea that the vines are well started, and are able to " stand it better "; this is also the time when sudden seemingly inexplicable failures of resistant vineyards are recorded. The vineyardist could prevent more actual cash-loss than he is aware of, if he would but test each joint and mercilessly reject everything that is not perfect. This point is dwelt on somewhat at length because it is one that is of vital importance, and one that is most frequently ignored. In planting young rooted vines great care should be given to the operation, or loss will result. As has been said, the American vine insists on greater care in planting and in the preparation of the soil than the European vines. Unless the vine-planter is prepared to give it this extra care and attention, he is strongly advised not to plant vines at all, for he will surely lose the money invested. The soil should have been plowed at least once, with a four-horse sulky plow, as deep as the plow can be 'driven even if a couple of extra horses have to be called in to pull it. It is of course an expen- sive operation, but it pays, and pays well, to incur it. As before remarked, land thus prepared will yield paying crops two years sooner than if the ordinary method of plowing be pursued, besides avoiding the risk of the loss of the entire vineyard. The poorer the land the deeper it should be plowed, and the more compact the land the deeper it should be plowed. As has been remarked, this is no theory of the writer, but a fact established beyond the possibility of rational doubt. The vines are planted at the usual distance, except that in the case of planting a resistant vineyard on the same soil that has for years nour- ished another one, care should be taken not to plant in the same holes from which vines were dug, but in the middle of the space between the rows. And it is also as well to previously fertilize the land, for it must be remembered that the roots of the young vine are too short and as yet too feeble to search for all the food the plant requires; so that in start- ing it should be aided. The holes should be dug with a shovel or spade. The custom of using a " post-hole digger " or a crowbar, or merely opening a slight space with a shovel and jamming the roots down behind the shovel, are common customs in certain places. These customs cannot be too severely condemned. They are responsible for the loss of enormous sums of money to the State. Holes should be as carefully dug as for fruit trees or any kind of valuable plant. There should be plenty of FIG. II. FIG. 12. Fig. 11. A six-year-old vine badly grafted, perishing from phylloxera on roots from scion. Fig. 12. Old grafted vine showing almost normal difference between size of stock and scion. FIG. 13. Fig. 13. Rupestris cutting-stock, showing manner of removing eyes. RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 53 loose soil at the bottom of the hole, and there should be plenty of room on the sides. Above all, the roots should be so arranged that they will not cling together in a " rope " or be bent upward (as I have seen so often the case) ; but they should be given a downward slope, so that they will at once " go down," especially in the case of dry ground. Some have found that in such dry soil it pays to put in the bottom of the hole, six inches below the roots, a shovelful of well-rotted stable manure. This prevents the roots from going along the surface, as some of the species tend to do naturally, and at the same time shuts out the danger of being torn by the plow, or affected by slight droughts. After the second year the American-rooted vineyard will be found to require extra care, and will be found to yield heavier crops than ever were produced by the same varieties on their own roots. For the first two years, and in some cases for three, the roots of the scion should be removed annually. After three years this will not be necessary. If it is neglected the scion will grow entirely away from the stock, and then, when the phylloxera attacks the roots of the scion, the vine becomes so enfeebled that nothing can be done with it. o UNIVERSITY OF CALIFORNIA. AGRICULTURAL EXPERIMENT STATION. BERKELEY, CAL. E. W. HILGARD, DIRECTOR. BULLETIN No. 119. DECEMBER, 1897. VINE PRUNING. BY F. T. BIOLETTI. The literature relating to the pruning and training of the vine is already very voluminous, but there seems to be no one work which treats the subject in a thorough and convenient way for California vine-growers. Publications in English refer generally to methods suited to the Eastern States or to hot-house cultivation, while for- eign publications, besides being more or less inaccessible, treat the subject 30 widely that the grower is at a loss what to choose from such a mass .of material. It is the purpose of this Bulletin, there- fore, to present a brief summary of what in foreign methods seems useful and applicable to California conditions, together with the results of experiments on the University of California vine plots, and of observations made in numerou s vineyards in various regions of the State. Almost every vine-growing district has its peculiar systems of training, ranging from the non-training usual in parts of Italy, where the vine spreads almost at will over trees planted for the purpose, to the acme of mutilation practiced in many localities where the vine is reduced to a mere stump barely rising above the surface of the ground. These various systems will not be discussed here, but only those which experience has shown to be most adapted to California conditions. No account, however detailed, of any system can replace the in- telligence of the cultivator. For this reason the general principles of plant physiology which underlie all proper pruning and training are discussed in connection with the several systems described. This should aid the grower in choosing that system most suited to the con- ditions of his vineyard, and to modify it to suit special conditions and seasons. All the operations of pruning, tying, staking, etc., to which a cultivated vine owes its form, are conveniently considered together. No cultivated plant is susceptible of such a variety of modes of training as the vine, and none can withstand such an amount of abuse in this matter and such radical interference with its natural mode of growth. On the other hand, no other plant, perhaps, is so sensitive to proper treatment, or responds so readily to a rational mode of pruning and training. OBJECTS OF PRUNING. The objects of pruning are (a) to facilitate cultivation and gathering, (b) to. increase the average yield, and (c) to improve the quality of fruit. The vine must not be trained so high that the grapes are difficult to gather, nor al- lowed to spread its arms so wide that the cultivation of the ground is unduly interfered with. Vines untouched by the pruner's knife bear irregularly; a year of over-bearing being followed by several of under-bearing as a consequence of exhaustion caused by a too severe drain on the reserve forces of the plant. The grapes on untrained or improperly trained vines are exposed to different conditions of heat and light, and consequently develop and ripen unevenly. PHYSIOLOGICAL PRINCIPLES. The main facts regard- ing the physiology of the vine to be kept in mind in this connection are : 1. The vine feeds by means of the green coloring matter (chloro- phyll) of its leaves. It obtains the sugar, starch, etc., which it needs from the carbonic acid of the air which is converted into these sub- stances by the chlorophyll under the influence of light. A certain amount of green leaf surface functioning for a certain time is neces- sary to produce sufficient nourishment for the vital needs of the vine and for the production of a crop. Those leaves most exposed to the direct rays of the sun are most active in absorbing food. The youngest leaves take all their nourishment from the older parts of the plant: somewhat older leaves use up more nutrient material in growing than they absorb from the air. A young shoot may thus be looked upon as, in a sense, parasitic upon the rest of the vine. The true feeders of the vine and of its crop are the mature, dark-green leaves. 2. Within certain limits the fruitfulness of a vine or of a part of a vine is inversely proportional to its vegetative vigor. Methods which tend to increase the vegetative vigor of a vine or of a part of a vine tend to diminish its bearing qualities, while, on the con- trary, anything which diminishes vegetative vigor tends to increase fruitfulness. Failure to reckon with this fact and to maintain a proper mean between the two extremes leads, on the one hand, to comparative sterility, and, on the other, to over-bearing and prema- ture exhaustion. 3. The vine tends to force out terminal buds and to expend most of its energy on the shoots farthest from the trunk. To keep the vine within practical limits, this tendency must be controlled by the removal of the terminal buds, or bv measures which check the flow of sap and force the growth of buds nearer the stock. 4. The nearer a shoot approaches the vertical the more vigorous it will be. 5. The size of shoots and of fruit is, within certain limits, in- versely as their amount. That is, with a given vine, or arm of a vine, the fewer shoots allowed to grow the larger each will be, and the same is true of bunches of fruit. 6. Other conditions being equal, an excess of foliage is accom- panied by a small amount of fruit; an excess of fruit' by diminished foliage. 7. Shoots coming from one-year-old wood growing out of two- year-old wood are alone to be depended on for fruit. Other shoots are usually sterile. , ,' 8. Bending, twisting or otherwise injuring the tissues of the vine or its branches tend to diminish its vegetative vigor, and there- fore, unless excessive, to increase its fertility. A description of a typical vine giving the names of the principal parts, will make clear the accounts of methods to be given later. Fig. i represents a vine of no particular order of pruning, showing the various parts. The main body of the vine (T) is called the trunk or stem; the principal divisions (B) branches; the smaller di- visions (A) arms, and the ultimate ramifications (C) shoots when green, and canes when mature. A. shoot growing out of the vine above ground on any part older than one year (WS) is called a water sprout. Shoots coming from any part of the vine below ground (S) are called suckers. When a cane is cut back to I, 2, 3, or 4 eyes it is called a spur (R). When a shoot or cane of one season sends out a secondary shoot the same season, the latter (L) is called a lateral. Fig. II represents an arm of a vine as it appears in winter after the leaves have fallen. The canes (Wi) are the matured shoots of the previous spring. W2, W3, W4 represent 2, 3, and 4-year-old wood respectively. Near the base of each cane is a basal bud or eye (B). In counting the number of eyes on a spur the basal eye is not included. A cane cut at Ki for instance leaves a spur of one eye, at K.2 a spur of two eyes and so on. When more than four eyes are left the piece is generally called a fruiting cane (Fig. I, F). The canes (C,Ci) coming from two-year old wood (W2) possess fruit buds; that is, they are capable of producing fruit - bearing shoots. Water sprouts (WS) and suckers (S) do not ordinarily produce fruit-bearing shoots. Below the basal bud each cane has one or more dormant buds (b Fig. Ill) which do not grow unless the number of eyes left by pruning or frost is insufficient to relieve c the excess of sap pressure. These buds produce sterile shoots. Each eye on a cane has, at its base, two dormant buds. One of these sometimes grows out the year it is formed, making a lateral (L, Figs. I, II). These laterals may send out secondary laterals (SL, Fig. I). It is on the laterals and secondary laterals jthat the so-called second and third crops are borne. PRUNING FOR WOOD AND FOR FRUIT. One of the chief aims of pruning is to maintain a just equilibrium between vege- tative vigor and fertility. We must, then, prune for both wood and fruit. A vine which has become enfeebled by over-bearing should be pruned for wood. By this is meant that only a small number of buds should be left. As all the energies of the vine have to be ex- pended on a small number of shoots, these shoots grow with more than ordinary vigor. Under these conditions the vine bears little; first, because the eyes near the bases of the canes, which are the only ones left in very short pruning, are naturally less fruitful than those farther removed from the main body of the vine; and second, because an exceptionally vigorous shoot is generally sterile. The vine is thus strengthened, and, as the stores of nutriment provided by a vigorous vegetation are not drawn upon by a heavy crop, the increased vigor of the vine is more marked the second year. The second year, there- fore, more wood may be left and the crop increased without detri- ment to the vine. On the other hand, a vine which " goes to wood " must be pruned for fruit. For this purpose we increase the number of buds left and choose the most fruitful wood. The largest canes are the least fruitful, while the smallest have not the necessary vigor to sup- -De- a large crop. The best cane to leave for fruit then is one of medium size, with well-formed eyes. PROPER METHOD OF MAKING CUTS. It is by no means a matter of indifference just where the cut is made in removing a cane or arm. This will be made clearer by referring to Eig. III. The upper part of the spur is rep- resented as split in two longitudi- nally in order to show the internal structure of the cane. It will be noted that at each bud there is a slight swelling of the cane. This is called a node, and the space be- tween an internode. The inter- nodes are filled with soft pith, but at each node there is a growth of hard wood extending through the cane. Now, if the cane be cut oft at C i, in the middle of an internode, the pith will shrink away and leave a little hollow in which the rain collects. This is an excellent breed- ing place for fungi and bacteria, which cause rotting of the pith and frequently kill the bud. If, on the contrary, the cane be cut at C2, through a node, a protecting cover of hard wood is left, which is an effectual barrier against decay organisms. If a spur projects too far from the vine and it is desirable to make it as short as possible in order not to interfere with cultivation, it should be cut at C and the cut made as nearly vertical as possible. This allows the water to run off, and leaves less pith to foster the growth of the fungi. At the base of the cane there is a slight enlargement (E). In removing a cane completely the cut should be made just above this enlarge- ment. This is the most favorable place for healing, as it makes the smallest possible wound and does not leave a projecting stump of dead wood to prevent the healing tissues from closing over the wound. In removing a piece of older wood, as at K and Ti, Fig. II, it is advisable not to cut too close for fear of injuring the spur by the drying out of the wood. The projecting pieces of dead wood left in this way should be carefully removed the next year in order to allow the wound to heal over. The large cuts which are thus occasionally necessary are most easily performed by means of a well-made and well-sharpened pair of two-hand pruning shears. These shears are often to be preferred to the ordinary one-hand shears be- cause they render the cutting through the nodes easier and do away almost entirely with the necessity of a saw. Of course, a careless workman may split and injure vines seriously by using long-han- dled shears clumsily, but the bending of arms to facilitate cutting with the one-hand shears often results in the same evil. The one- hand shears, however, are more convenient when many long fruit- ing canes are left, as the necessary trimming off of tendrils and lat- erals is more easily performed with them. SHORT AND LONG PRUNING. The winter-pruning of the vine consists in cutting off a certain amount of the mature wood of the immediately preceding season's growth (canes), and occa- sionally of the older wood. The main problem of winter-pruning, then, resolves itself into determining how much and what wood shall be left. In all kinds of pruning most of the canes are removed en- tirely. In short-pruning, the remainder are cut back to spurs of one, two or three eyes. The number of spurs is regulated by the vigor and age of the vine. This mode of pruning can be used only for varieties in which the eyes near the base of the cane are fruitful. For all other cases long or half-long pruning is necessary. In half -long pruning certain canes are left with from four to - six eyes, according to the length of the internodes. These canes or fruit- spurs will bear more fruit than short spurs for three reasons: I, be- cause there will be more fruit-bearing shoots; 2, because the upper eyes are more fruitful than the lower; and 3, because a larger num- ber of eyes being supplied with sap from the same arm, each shoot will be less vigorous and therefore more fruitful. Owing, however, to the tendency of the vine to expend the principal part of its vigor on the shoots farthest removed from the base of the canes, the lower eyes on the long spurs will generally produce very feeble shoots. In order, then, to obtain spurs of sufficient vigor for the next year's crop it would be necessary to choose them near the ends of the long spurs of the previous year, if no others were left. This would result in a rapid and inconvenient elongation of the arms. In order to avoid this it is necessary to leave a spur of one or two eyes below each long fruiting spur, that is to say, nearer the trunk. These short wood spurs having only one or two eyes, will produce vigorous canes for the following year, and the spurs which have borne fruit may be re- moved altogether, thus preventing an undue elongation of the arms. In half-long pruning, however, it is very hard to retain the proper equilibrium between vigor and fruitfulness. If a little too much wood is left the shoots from the wood spurs will not develop sufficiently, and the next year we have to choose between leaving small under-sized spurs near the trunk and spurs of proper size too far removed from the trunk. In long pruning this difficulty, as will be seen, is to a great extent avoided. In long pruning the fruit spurs of half-long pruning are re- placed by long fruit canes. These are left two or three feet long, or longer. The danger here that the vine will expend all its energies on the terminal buds of these long canes and leave the eyes of the wood spurs undeveloped is still greater than in half-long pruning. This difficulty is overcome by bending or twisting the fruit canes in some manner. This bending causes a certain amount of injury to the tissues of the canes, which tends to check the flow of sap towards their ends. The sap pressure thus increases in the lower buds and forces them out into strong shoots to be used for spurs for the next pruning. The bending has the further effect of diminishing the vigor of the shoots on the fruit canes and thus increasing their fruitfulness. This principle of increase of fruitfulness by mechanical injury is very useful if properly understood and applied. It is a well-known fact that vines attacked by phylloxera or root rot will for one year bear an exceptionally large crop on account of the diminution of vigor caused by the injury to their roots. A vine also which has been mutilated by the removal of several large arms will often produce heavily the following year. In all these cases, however, the transient gain is more than counter-balanced by the permanent injury and loss. The proper application of the principle is to injure tissues only of those parts of the plant which it is intended to remove the next year (fruit canes), and thus increase fruitfulness without {icing any permanent injury to the plant. PRUNING OF YOUNG VINES. When a rooted vine is first planted, it should be cut back to two eyes. If the growth is not very good the first season, all the canes but one should be removed at the first pruning, and that one left with two or three eyes, according to its strength. The next year, or the same year in the case of strong grow- ing vines in rich soil, the strongest cane should be left about 12 inches long and tied up to the stake The next year two spurs may be left, of two or three eyes each. These spurs will determine the posi- tion of the head or place from which the arms of the vine spring. It is important, therefore, that they should be chosen at the right height r'rom the ground. From ten to twenty inches is about the right height; the lowest for dry hillsides where there is no danger of frost; the highest for rich bottom lands where the vine will naturally grow large. Vines grown without stakes will have to be headed lower than this in order to make them support themselves. In the following few years the number of spurs should be increased gradually, care being taken to shape the vine properly and to maintain an equal balance of the arms. In general, young vines are more vigorous than old, and tend more to send out shoots from basal and dormant buds. They should, therefore, be given more and longer spurs in proportion than older vines. They also tend to bud out very early in the spring, and are thus liable to be frost-bitten. For this reason they are generally pruned late (March) in frosty locations. This protects them in two ways. In the first place, in unpruned vines the buds near the ends of the canes start first and relieve the sap pressure, and though these are caught by the frost the buds near the base, not having started, are saved. In the second place, the pruning being done when the sap is flowing there is a loss of sap from the cut ends of the spurs which further relieves the sap pressure and retards the starting of the lower eyes. This method of preventing the injury of spring frosts by very late pruning has been tried with bearing vines, but is very injurious. Older vines being less vigorous are unable to withstand the heavy drain caused by the profuse bleeding which ensues; and though no apparent damage may be done the first year, if the treatment is continued they may be completely ruined in three or four years. . SYSTEMS OF PRUNING. The systems of pruning adapted to vineyards in California may be divided into six types according to the form c,-'\en to the main body of the vine t \nd the length of the spurs and fruiting canes. A. Vine pruned to a head, with short arms. I. With spurs of two or three eyes only (short pruning). II. With wood spurs of one or two eyes and fruit spurs of four, to six eyes (half-long pruning;. III. With wood spurs of one or two eyes and long fruit canes, (long-pruning). B. Vine with a long horizontal branch or continuation of the trunk. IV. With spurs of two or three eyes only (short pruning). V. Wjth wood spurs of one or two eyes and fruit spurs of four to six eyes (half-long pruning). VI. With wood spurs of one or two eyes and long fruit canes (long-pruning). These types are applicable to different varieties of vines according (i) To the natural stature of the vine that is to say, whether it is a large of small grower and tends to make a large, extended trunk or a limited one. (2) To the position of the fruit buds. In some varieties all the buds of the canes are capable of producing fruitful shoots, while in others the one, two or three buds nearest the base produce only sterile shobts. (3) To the size of the individual bunches. It is necessary in order to obtain a full crop from a variety with small bunches to leave a larger number of eyes than is necessary in the case of varieties with large bunches. What type or modification of a type shall be adopted in a par- ticular instance depends both on the variety of vine and on the nature of the vineyard. A vine growing on a dry hillside must not be pruned the same as another vine of the same variety growing on rich bottom land. In general, vines on rich soil, where they tend to grow large and develop abundant vegetation, should be given plenty of room and allowed to spread themselves, and should be given plenty of fruiting buds in order to control their too strong inclination to ''go to wood." Vines on poor soil, on the contrary, should be planted closer togeth- er and pruned shorter, or with fewer fruiting buds, in order to main- tain their vigor. Type I. This is the ordinary short pruning practiced in 90 per cent of the vineyards of California, and is the simplest and least ex- pensive manner of pruning the vine. It is, however, suited only to vines of small growth, which produce fruitful shoots from the lowest buds, and of which the bunches are large enough to admit of a full crop from the small number of buds which are left by this method. The chief objection to this method for heavily bearing vines is that the bunches are massed together in a way that favors rotting of the grapes and exposes the different bunches unequally to light and heat. Fig. IV. represents the simplest form of this style of pruning. The vine should be given, as nearly as possible, the form of a goblet, slightly flattened in the direction of the rows. It is important that the vine be kept regular and with equally balanced arms. This is the chief difficulty of the method and calls for the exercise of some judgment. From the first, the required form of the vine should be kept- in view. On varieties with a trailing habit of growth vertical spurs must be chosen, and with some upright growers it will be found necessary to choose spurs nearer the horizontal. The arms must be kept short for convenience of cultivation and to give them the requisite strength to support their crop without bending or breaking. For this reason the lowest of the two or three canes coming from last year's spur should be left. For instance, on Fig. II the cane should be cut at K2 or K/3, according as two or three eyes are needed, and the rest of the arm removed at K. As even with the greatest care some arms will become too long or pro- ject in wrong directions, it is necessary to renew them by means of canes from the old wood or water sprouts. For instance, if the other arm represented on Fig. II were too long, it should be removed and replaced by another developed from the cane (WS). As the cane comes from three-year-old wood it cannot be depended on to pro- duce grapes. "For this reason it is best the first year to prune the arm at T, leaving a spur for fruit, and cut the water sprout ait T leav- ing a wood spur of one eye. The next year the cane coming from the first eye of WS can be left for a fruit spur, and the arm removed at Ti. The cutting back of an elongated arm should not be deferred too long, as the removal of old arms leaves large wounds which weak- en the vine and render it liable to attacks of fungi. In order to maintain the equilibrium of the arms it is often nec- essary to prune back the more vigorous arms severely in order to throw the strength of the vine into the weaker arms. If the vine ap- pears too vigorous, that is if it appears to be "going to wood" at the expense of the crop, two spurs may be left on some or all of the arms. In this case the upper spur should be cut above the third eye (K4 Fig. n), and the lower above the first or second (Ki or K.2). This will cause the bulk of the fruit to be borne on the upper spur, and the most vigorous shoots to be developed on the lower, which provides the wood for the following year. This is an approach to the next (half- long) method of pruning. Type II. Vines which require more wood than can well be given by ordinary short pruning, or of which the lower eyes are not suffi- ciently productive, may in some cases be pruned in the manner il- lustrated by Fig. V. For some va- rieties it is necessary to leave spurs of only three eyes, as at S; for others, short canes of four or five 10 eyes must be left, as at CC. These shorter spurs can be left without support, but the longer ones require some arrangement to prevent their bending over with the weight of fruit and destroying the shape of the vine. In some cases simply tying the ends of the canes to- gether will support them fairly well, but it is better to attach them to a stake and bend them at the base a little when possible in order to retard the flow of sap to the ends. It is very necessary to leave strong spurs of one eye (not counting the basal eye) in order to provide wood for the following year. At the pruning following the one represented in the cut the fruiting part of the arms will be removed at KK and a new fruiting spur or cane, made of the cane which comes from the eye on the wood spurs W. The basal bud on W will in all probability have produced a cane which can be cut back to one eye to furnish a new wood spur. If this is not the case it shows that too much wood was left the first year, and therefore no fruit cane should be left on this arm, but only a single spur of two or three eyes. This will be a return to short pruning, and must be resorted to whenever the small size of the canes or the failure to produce replacing wood near the head of the vine shows that the vigor is diminishing. If, on the contrary, the arm shows an abundance of vigorous canes, proving that the vine has not overborne, a fruit cane may be left from one of the shoots coming from the lower buds of the fruit cane C, and a new wood spar of two eyes left on the shoot coming from the wood spur of the previous year (W). In this case, the removal of the arm at K is deferred one year, and the extra vigor of the vine is made use of to produce an extra crop. Type III. This style is an ex- tension of the principles used in type II, as will be understood by referring to Fig. VI. The fruiting canes are left still longer, and in some cases almost the full length of the cane. As each cane will thus produce a large amount of fruit, fewer arms are necessary than in the preceding method. It is es- pecially necessary to leave good, strong spurs of one or two eyes to produce wood for the following year. There are various methods of disposing of the long fruiting canes, the worst of which is to tie them straight up to the stake, as was recommended for the half-long canes. In the latter case, owing to their shortness, ,a certain amount of bending of the canes is possible with this method of tying. With long canes, on the contrary, it usually allows of no bending, and as a result there ensues a vigorous growth of shoots at the ends of the fruiting canes, and little or no growth in the parts where it is necessary to look for wood for the following year. Often, indeed, each long cane will produce only three shoots and these from the three terminal eyes, all the other eyes of the cane remaining dormant. The object of long pruning is thus doubly defeated, ist because no more shoots II are produced than by short pruning, and 2nd, because the shoots which should produce fruit are rendered especially vigorous by their terminal and vertical position, and therefore less fruitful. Each year all this vigorous growth of wood at the ends of the canes must be cut away in order to keep the vine within practical bounds, and the fruit canes renewed from the less vigorous cane below. These canes ate less vigorous because the main strength of the vine has been ex- pended on the upper canes which are most favorably placed for vege- tative vigor. Vines treated in this way may be gradually exhausted though producing only a moderate or small crop of fruit, by being forced to produce an abundant crop of wood. One of the simplest ways of tying the fruiting canes is illus- trated by Fig. VII. The canes are bent into a circle, the ends tied to the stake near the head of the vine, and the middle of the circle at- tached higher up. The tying should be done so that the cane receives a severe bend near the base that is about the region of the second and third eyes. This can usually .be accomplished by ty- ing the end of the cane first, and then pressing down on the middle of the bow until , the desired bend is attained. If two fruiting canes are left, they should be made to cross each .other at right angles in order to distribute the fruit as equally as possible. As a rule more than two canes should not be tied up in this way as it makes too dense a shade and masses the fruit too much. Fig. VIII shows another method of tying the long canes. A horizontal wire is stretched along the row at about fifteen to twenty inches above the ground. To this the fruiting canes should be at- tached, using the same precaution of bending the canes near the bases. The upper part of the canes is not bent in this case as in the last, but the necessary diminution of vigor and increase of fruitfulness is brought about by the horizontal position. Two canes may be attached to the wire on each side. The stake is best used to support the 12 shoots destined for the wood for the following year. This makes it possible, where topping is practiced, to cut off the ends of the shoots from the fruiting canes and to leave the rest their full length. Another or even two other wires may be used above the first for more canes, but this is seldom profitable, and considerably increases the cost both of installation and or pruning. This style of pruning is especially favorable to varieties of small growth which bear small bunches and principally on the upper eyes, and to varieties of larger growth in hilly or poor soils. One of its main objections is that it renders some varieties more liable to sun- burn. It will be noticed that the long-pruned vines are represented in the figures as having much fewer arms than the short-pruned. This is necessary and important. In order to maintain a well-balanced vine and keep it under control, there should be only about as many arms as long canes, or at most one, or two more. Types IV, V and VI. The .three styles of pruning so far de- scribed have been fairly thoroughly tested in .California, and each has been found applicable to certain varieties and conditions. There are some varieties, however, which do not give good results with any of these systems. This is the case with many valuable table grapes, es- pecially when grown in rich valley soil, where they should do best. For these cases some modification of the French cordon system is to be recommended. Little trial of this method has been made as yet, but what has been done is very promising. The tendency of many grapes to coulure is overcome, and rich soils are made to produce crops in proportion to their richness. The method consists essentially in allowing the vine to grow in a more or less horizontal direction for several feet, thus giving a larger body and fruiting surface. The treatment of the young vines the first year is the same as for head pruning, as already described. As soon as the young vine pro- duces a good, strong shoot it is tied up to the wire and to the stake which is placed between the vines in the rows. Each vine should finally reach, its neighbor, but it requires two or three years for this if the vines are six or seven feet apart in the rows. It is possible by cutting the vine back nearly to the ground for the first year or two to obtain a cane which will stretch the whole distance between the vines at the first tying up; but this is not necessary nor advisable. Neither is it advisable to make a very sharp angle (almost a right angle) as is usually done in regular cordon pruning, on account of 13 the difficulty of preventing the vine from sending out an inconvenient number of shoots at the bend. The vine might be grown with two branches, one stretching in either direction, but this has been found inconvenient on account of the difficulty of preserving an equal bal- ance of the branches. The direction in which the vine is trained should be that of the prevailing high winds, as this will minimize the chances of shoots being blown off. When the cordon or body of the vine is well-formed, it may be pruned with all the modifications of short, half-long and long pruning already described in head pruning, and the same precautions are necessary to preserve the balance and symmetry of the vine and to maintain it at the highest degree of fruit- fulness without undulv exhausting it. Figs. IX and X will sufficiently illustrate the way of shaping and tying short and long-pruned vines. For some table grapes extension of the method shown in Fig. IX in the direction of half-long pruning is useful. On a heavy soil the short spurs do not provide sufficient outlet for the vigor of the vine, while long pruning would unduly in- crease the number of bunches on a single cane, and so reduce their size, which would deteriorate from their value as table grapes. Fig. XI represents a style of pruning used with success in some of the richest low-lying soils of France. The body of the vine is rais- ed up to a height of two and a half or three feet above the soil, a use- ful means of lessening the danger from spring frosts. The fruit canes are bent vertically downward thus restricting the flow of sap sufficiently to force out the lower buds of the fruit canes into strong shoots which can be used for fruit canes of the follow- 14 ing year. This does away, to some extent, with the necessity of leaving wood spurs, and much simplifies the pruning. Arms, of course, are formed in time, and very gradually elongate, so that it is necessary to remove one occasionally and replace it by a water sprout, as already explained under short pruning. SUMMER PRUNING. Some form of summer or green pruning is practiced in most Cal- ifornia vineyards, if in the term we include all the operations to which the green shoots are subjected. There seems, however, to be little sys- tem used, and very little understanding of its true nature and object. In general, it may be said that green pruning of the vine is least need- ed and often harmful in warm, dry locations and seasons, and of most use under cool and damp conditions. The principal kinds of green pruning are: I. pinching; 2. suckering and sprouting; 3. topping; 4. removal of leaves. Pinching consists in removing the extreme growing tip of a young shoot. It is necessary to remove only about half an inch to ac- complish the purpose of preventing further elongation of the shoot as all growth in length takes place at the extreme tip. The immediate result of pinching is to concentrate the sap in the leaves and blos- soms, of the shoot, and finally to force out the dormant buds in the axils of the leaves. It has been found useful in some cases to com- bat coulure or dropping with heavy-growing varieties, such as the Clairette Blanche. It is also, of use in preventing unsupported shoots from becoming too long while still tender, and being broken off by the wind. It can, of course, be used only on fruiting shoots and not on shoots intended for wood for the following year. Suckerinq is the removal of shoots that have their origin below or near the surface of the ground. The shoots should be removed as thoroughly as possible, the enlargement at the base being cut off in or- der to destroy the dormant basal buds. An abundant growth of suckers indicates either careless suckering of former years, (which has allowed a mass of buds below the ground, a kind of subterranean arm, to de- velop, or too limited an outlet for the sap. The latter may be due to frost or other injuries to the upper part of the vine, but is commonly caused 'by too close pruning. Sprouting is the removal of sterile shoots or "water-sprouts" from the upper part of the vine. Under nearly all circumstances this is an unnecessary and often a harmful operation, especially in warm, dry locations. An exception may perhaps be made under some conditions of varieties like the Muscat of Alexandria, which has a strong ten- dency to produce "water-sprouts" which, growing through the bunches, injure them for table and drying purposes. Water-sprouts are produced from dormant buds in the old wood, and as these buds require a higher sap pressure to cause them to start than do the fruitful buds, the occurrence of many water- sprouts indicates that too limited a number of fruitful buds has been left upon the vine to utilize all the sap pumped up by the roots. To remove these water-sprouts, therefore, while they are young is simply to -shut off an outlet for the superabundant sap and thus to injure the vine by interfering with the water equilibrium, or to cause it to force 15 out new water-sprouts in other places. Any vigorous vine will pro- duce a certain number of water-sprouts, but they should not be looked upon as utterly useless and harmful because they produce no grapes. On the contrary, if not too numerous, they are of positive advantage to the v^ne, being so much increase to the feeding surface of green leaves. Water-sprouts should be removed completely during the win- ter pruning, and the production of too many the next year prevented by a more liberal allowance of bearing wood. Topping, or cutting off the ends of shoots, is done by means of a sickle or long knife. At least two or three leaves should be left be- yond the last bunch of grapes. The time at which the topping is done is very important. When the object is simply to prevent the breaking of the heavy, succulent canes of some varieties by the wind, or to facilitate cultivation, it must of course be done early, and is well re- placed by early pinching. These objects are, however, better attained by appropriate methods of planting and training. Early topping is in- advisable because it induces a vigorous growth of laterals which make too dense a shade, and it may even force the main eyes to sprout, and thus injure the wood for the next year. The legitimate function of topping is to direct the flow of food material in the vine first into the fruit, and second into the buds for the growth of the following year. If the topping is done while the vine is in active growth, this object is not attained; one growing tip is simply replaced by several. In this way, in rich, moist soils vines are often, by repeated toppings, kept in a continual state of production of new shoots, and as these new shoots consume more food than they .produce, the crop suffers. Not only does the crop of the current year suffer, but still more the crop of the following year, for the vine devotes its energy to producing new shoots in the autumn instead of storing up reserve food-matrial for the next spring growth. If, on the other hand, the topping is done after all leaf growth is over for the season, the only effect is to deprive the vine of so much food-absorbing surface. The topping, then, should be so timed that, while a further length- ening of the main shoot is prevented, no excessive sprouting of new laterals is produced. The exact time differs for locality, season and variety, and must be left to the experience and judgment of the indi- vidual grower. Removal of leaves. In order to allow the sun to penetrate to and aid the ripening of late grapes it is often advisable late in the season to lessen the leafy shade of the vine. This should be done by remov- ing the leaves from the center of the vines and not by cutting away the canes. * In this way only those leaves are removed which are injurious, and as much leaf surface as possible is left to perform the autumn duty of laying up food-material for the spring. The removal of leaves should not be excessive, and if considerable, should be gradual, other- wise there is danger of sunburn. It is best, first, to remove the leaves from below the fruit. This allows free circulation of the air and pene- tration of the sun's rays which warm the soil and are reflected upon the fruit. This is generally sufficient, and in any case only the leaves in the center of the vine, and especially those which are beginning to turn yellow should be removed. i6 In the list of varieties which follows, an attempt has been made to indicate the mode of pruning which is likely, in the light of our pres- ent knowledge, to give the best results for each variety. It should be understood, however, that it is to some extent tentative and provis- ional. Many of the varieties have proved successful in certain soils and locations when pruned in the way indicated, but others have never, so far as we know, been tested in the way proposed. As these latter, however, have proved more or less unsuccessful under the com- mon methods of treatment the method proposed is the one which seems most suitable to their habit and general characters. It seems probable that the tendency to coulure of some varieties such as the Muscat, Malbeek, Merlot, Clairette, etc., can be combatted to a great extent by appropriate methods of pruning and training. Unevenness of ripening and liability to sunburn of Tokay, Zinfandel, etc., can doubtless be controlled by the same means. Very few varieties succeed under strictly short pruning, that is cutting back to one and two eyes, so that for most of the varieties in the first category the modification of short pruning which gives fruit spurs of three or four eyes and wood spurs of one eye is recommended. Type I. Charbono, Cinsaut, Mataro, Carignane, Grenache, Petit and Alicante Bouschet, Aramon, Mourastel, Verdal, Ugni-blanc, Folle blanche, Burger, Zinfandel, Griiner Velteliner, Peverella, Zier- fahndler (?), Rother Steinschiller (on poor soils), Slankamenka, Green Hungarian (on poor soils), Blue Portuguese (on poor soils), Tinta Amarella, Moscatello fino, Pedro Ximenes, Palomino, Beba (?), Pe- runo, Mantuo, Mourisco branco, Malmsey, Mourisco preto, Feher Szagos, Muscat of Alexandria, Sultanina, Sultana,, Barbarossa. Type II. St. Macaire, Beclan (longer or shorter according to rich- ness of soil), Teinturier male, Mon dense; Marsanne, Chasselas, Mus- catel, Grosse Blaue, Sauvignon blanc,/ Sauvignon vert, Nebbiolo, Fresa, Aleatico. Type III. Cabernet Sauvignon and Cabernet Franc (on poor soils and hillsides), Verdot, Tannat, Gamai Teinturier, Gros Mansenc, Pinots, Meunier, Gamais, Pinot blanc, Pinot Chardonay, Rul^nder, Afrenthaler, Johannisberger, Franken Riesling (on hillsides), Klein- berger, Traminer, Walschriesling, Rothgipfler, Lagrain (? perhaps short), Marzemino, Blue Portuguese (on rich soils), Barbera, Moret- to, Refosco, Tinta de Madeira, Tinta Cao, Verdelho, Boal. v <" Type IV. Green Hungarian, Rother Steinschiller (on rich soils), Neiretta, Mission, West's Prolific, Robin noir. Type.V. St. Macaire and Mondeuse (on ricli bottom soils], Tinta Valdepenas, Marsanne, Clairette blanche, Semillon, Sauvignon blanc (on rich soils), Muscadelle du Bordelais, Vernaccia bianca, Furmint Bakator, Tadone, Gros Colman, Black Morocco (?), Cornichon (?), Emperor, Tokay (?), Almeria, Pizzutello, California black Malvoisie. Type VI. Malbec, Petite Strah and Serine, Cabernet Sauvignon and Cabernet Franc (on rich bottom soils), Merlot, Gros Mansenc (.? on rich bottom soils), Chauche noir, Bastardo, Trousseau, Ploussard, Etraie de TAdhui, Chauchd gris, Franken Riesling (on rich soils). UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE, AGRICULTURAL EXPERIMENT STATION. E. W. HILGARD, Director. REPORT ON CONDITION OF VINEYARDS IN PORTIONS OF SANTA CLARA VALLEY. BY FREDERIC T. BIOLETTI AND E. H. TWIGHT. DECAYED TRUNK. (See page 4.) BULLETIN No. 134. (Berkeley, Sept. 23, 1901.) SOUND TRUNK. SACRAMENTO: A. j. JOHNSTON, ::::::: SUPERINTENDENT STATE PRINTING. 1901. UNIVERSITY OF CALIFORNIA, COLLEGE OP AaHICULTtmE, AGRICULTURAL EXPERIMENT STATION. E. W. HILGABD, DIRECTOR. BERKELEY, CALIFORNIA. AUGUST 26, 1901. PROFESSOR E. W. HILGARD, Director of Agricultural Experiment Station. DEAR SIR: In accordance with your directions we have examined the vineyards of Santa Clara with the object of determining the cause of the failure and death of a large number of vines in parts of that county during the last three years. It is not possible at present to give a com- pletely satisfactory explanation for such serious and widespread damage as has occurred, but our observations seem to prove conclusively two propositions: First, that the dying vines exhibit symptoms differing materially from those shown by the vines in Southern California which were destroyed by the Anaheim disease; and, second, that whether or not there be some u unknown influence " at work, as suggested by Mr. Newton B. Pierce, the real, determining factor is the deficiency of rain- fall during the years 1897-1900. Area and General Character. The dying of vines without perceptible adequate cause during the last three years has by no means been con- fined to the west side of the Santa Clara Valley. Similar cases have been reported and investigated over a wide area extending from the northern part of Sonoma County, to the western and southern parts of the Santa Clara Valley, and including nearly all the older vineyard districts within these limits. The only peculiarity of the cases on the west side of the Santa Clara Valley is their number, extending in many cases to every vine in a vineyard. The distribution of the injured and dead vines is not in any of the cases examined such as to suggest an infectious parasitic cause. In some instances single vines failed and died sporadically where the main bulk of the vineyard was in fair con- dition, and a dead vine was usually surrounded by vines which were apparently healthy. Nature of Injury. In most of these sporadic cases examined the dying vine was found to have been severely injured in some way, usually by cutting off large branches at the pruning and thus causing large wounds. Vines of this kind when split open were found to be more or less decayed in the middle, and many were quite hollow. In a report made to you last year on the same subject this decay of the interior of the trunk was suggested as the cause of death in some cases. This year, however, though in some vineyards the hollow vines have continued to fail and die, in others they have recovered. This indicates that though the wood decay may have contributed to the effect, it is not the only, nor indeed the chief cause. The accompanying photograph (plate 1) illustrates the injury done hy the cutting off of a large branch. Note in the subjoined figure the large wound which could not heal over, and which allowed a large amount of wood to dry out. Note also PLATE 1. VINE INJURED BY HEAVY PRUNING WITHOUT PROTECTION TO WOUND. the hole made by a boring insect, which allowed the entrance of moisture and of white ants, and thus favored the growth of wood-rot fungi. The stem of this vine was found, on being split, to be quite hollow nearly down to the surface of the ground. For the general appearance of vines of this kind see the frontispiece, which is taken from a photograph of one of the vines as it appeared in 1900. Note the contrast with the perfectly healthy appearance of the neighboring vine. Nature of Soil. Nearly, if not quite, all the cases occurred in grav- elly soil, and the more gravelly the soil the more numerous and serious 5 the cases. Soil-borings in the most badly affected vineyards showed a layer of many feet of coarse gravel, commencing at two or three feet from the surface. In attempting to irrigate in these places the growers had much difficulty in causing the water to flow to all parts of the vine- yard. A large stream of water would take many hours in passing a few yards, on account of the extremely leachy nature of the soil, which allowed the water to escape downward. Age of Vines. It is to be noted that none of the dying vines are young. All the vineyards examined which were less than eight years old showed no indications of failing or dying. All cases of young vines PLATE 2. Two HEALTHY TROUSSEAU VINES IN A VINEYARD OF DEAD MATARO VINES. failing which were examined were plainly due to lack of cultivation, phylloxera, sunburn, or other well-known and adequate causes. Another fact worth mentioning in this connection is that old vines which were grafted just before the three dry years, are now nearly or quite healthy. In one vineyard a block of old Mataro grafted with Verdal about 1896 shows strong growth and no signs of failing, while a contiguous block of the same variety and age, but un grafted, is prac- tically dead. Behavior of Different Varieties. A great deal of difference was every- where noted in the behavior of different varieties of vines. The most seriously affected were Mataro, Zinfandel, Rose of Peru, Mission, Emperor, and Burger. Varieties less affected were Grenache, Muscat, 6 and Verdal. These three varieties, in many cases where they looked very bad last year and even this spring, appear to be recovering. Other varieties show little or no damage. The chief of these noticed were Trousseau, Cabernet-Sauvignon, Pinot (?), Verdot, Robin noir, and Herbemont. This list indicates that the heaviest bearers are the most seriously affected and that all the immune varieties are light bearers. This difference in varieties was so marked that several Trousseau vines growing in a Mataro block were apparently perfectly healthy and vigorous, while the Mataro were all dead. This is shown in the photo- graph (plate 2). The recovery of less susceptible varieties, such as Grenache, was in several cases very remarkable. Two adjacent blocks, one of Grenache and the other of Mataro, showed a remarkable contrast PLATE 3. ADJACENT BLOCKS OF MATARO (DEAD) AND GRENACHE (RECOVERING). when examined in August of this year. Both blocks had made very short growth in 1900, but this year all the Mataro were dead, while none, so far as could be seen, of the Grenache had died, and though the block had looked sickly in the spring, when examined in August it showed a fine growth of luxuriant foliage (see plate 3). To recapitulate; the main facts ascertained are: 1. All the dying vines are old. 2. All the serious cases are in gravelly soil. 3. The varieties most injured are all heavy bearers. 4. Vines grafted before the drought are healthy. 5. Vines showing serious mechanical injuries succumb first. 6. Vines which have not become too weak appear now to be recov- ering. Causes. These facts seem to indicate that we can ascribe the failure of the vines to a general cause acting over the whole district; a cause, however, which was only effective where supplemented by one or more contributory conditions. These conditions are: 1. Excessively gravelly soil. 2. Susceptibility of the variety of vine, due probably to heavy bearing and perhaps to some peculiarity of wood and foliage, or roots. 3. Large wounds made in pruning. 4. Age of the vine. 5. Severe cutting back of the young growth by spring frosts. The general cause seems to be the combined effect of the heavy crops of 1896 and 1897 and the four years of drought which followed. Rainfall and Crops. The following statistical table, made up from data furnished by the Weather Bureau and by two of the largest vine- growers in the most seriously affected districts, fortifies the above position : Relation of Precipitation and Irrigation to Crop, in Vineyards in Santa Clara Valley. Precipitation at Santa Clara. Crop on Vineyards at West Side. Departure from Normal Rainfall. A (300 acres). B (170 acres). 1896 Inches. 19.51 11.82 8.13 15.56 13.15 Tons. 1,413 1,883 500 a 449 6315 Tons. dSQQ d215 d 93 c 94 Inches. +3.24 -4.45 8.14 .71 3.12 1897 1898 1899 .. .. 1900 a Irrigated 35 acres. > Irrigated 300 acres. c Irrigated 70 acres in February. From 50 acres of the irrigated land were obtained 49 tons of grapes, and from the remainder of the vineyard only 45 tons. This indicates about 1 ton per acre on the irrigated and about % ton per acre on the unirrigated portion. d Estimated from the wine produced. If the figures given for these two vineyards are typical, which there is every reason to suppose, they may help us to find a sufficient cause for the death of the vines without taking refuge behind the mysterious and highly unsatisfactory Anaheim disease. In 1896 the vines bore a large crop, but were supplied with sufficient water by a rainfall of three inches above the normal. They therefore entered the season of 1897 healthy, but probably not with an excess of reserve food-material laid up in the stems and roots; for the weakening effect which a heavy crop often has upon a plant is due to the fact that the nutriment which it absorbs and assimilates during the summer and autumn is nearly all utilized in the production of fruit, and little is stored for use in the fol- lowing spring. The spring growth of a plant is all due to this reserve food, and is the weaker the less of this reserve it has to draw upon. Usually a year of heavy bearing is followed by a year of light bearing, during which the plant is able to recuperate by utilizing the food assimilated during that year for building up its vegetative organs and for replenishing its depleted reserve. During the season following the heavy crop of 1896, however, the weather conditions were evidently such as to force the vines to expend all their resources in the production of the phenomenally large crop of 1897. How exceptionally large this crop was upon the vines which are now dying is not quite indicated by the table above, which includes the crop from all varieties and ages of vines. The crop on the old vines of heavy-bearing varieties which are now dead was doubtless much in excess of the indicated average. At the same time that this severe drain was being made upon them there was a shortage of over four inches in the annual rainfall. It is practi- cally certain, therefore, that these vines were obliged to start the year 1898 with empty storehouses, and the rainfall of that year being just half the normal, the vines not only bore very little, but were unable to obtain nutriment sufficient to satisfy their vegetative needs and to nour- ish their permanent organs roots, stems, and canes. The next year, 1899, therefore, they commenced to fail and some of them to die. In 1900 still more died, while in 1901, the present year, the largest mortality of all occurred. It is, perhaps, not quite clear why the mortality should be greatest in the later years when the defi- ciency of rain was less than in 1898, the year of the greatest drought. It should be remembered, however, that a lack of water may affect a plant in two ways: If it occurs at a time when the plant is in vigorous growth and full leaf the plant is injured or killed by diminution of the amount of water in its cells and tissues, due to the excess of evaporation from the leaves over the absorption by the root hairs. In this case the plant dies of thirst and dies suddenly at the time of the drought. If there is, on the contrary, a chronic deficiency of water in the soil, com- mencing in the winter before the plant commences to grow, the result is simply a small, weak growth of foliage, insufficient to supply food for the needs of the stem and roots. The roots thus having a restricted food-supply fail to grow with normal vigor and in turn fail to supply the rest of the plant with the soil nutrients which it is their function to collect. We have in this latter case not so much injury from thirst as gradual starvation, which is slower in its action and probably, when several dry seasons follow each other, cumulative, as the reserve food- supply becomes each year more depleted until the plant dies. Summary. This, then, seems to us the true explanation of the death of vines in the Santa Clara Valley, stated in a few words: Slow starva- tion, due to excessive prolonged drought following two exceptionally heavy crops. That some vines have died and others have lived is due, as we have shown, to cooperating influences, the principal of which are the character of the soil, the variety of grape, the age of the vines, and the exhausting effect of late spring frosts in certain vineyards. The objection to the drought theory which has been made, that irri- gated vines have suffered as much as unirrigated, does not appear to be valid, as, in all the cases which we could find, the irrigation was applied too late. Very little irrigation was practiced until 1899, and then only upon the worst vineyards where the vines were already injured beyond redemption. The irrigation to have been effective, should have been given during the winter of 189798, the season of greatest drought, and immediately succeeding the two years of abnormally heavy crops. This would have insured the strong growth of foliage during the fol- lowing summer needed to repair the drain of the preceding years and to replenish the depleted stores of reserve food-supply in the trunk and branches. That irrigation was of some value, even when practiced late, is indicated by the record of vineyard B in the foregoing table, which shows that the irrigated portion of the vineyard produced four times the crop per acre produced by the unirrigated portion, though the amount of water used was only about three inches, or just enough to make up for the shortage in rainfall of the year. Young vs. Old Vines. The immunity of young vines, and of old vines which had been grafted about 1897, is explicable on the theory that they were enabled to withstand the drought because they did not bear in 1897 and were thus saved the drain of that heavy crop. The same reason may account to some extent for the immunity of certain light-bearing varieties. That vines on other soils and in other localities have escaped the destruc- tion that has overtaken the West-side vineyards is due doubtless to the fact that the three destructive factors of drought, heavy bearing, and leachy soil have not elsewhere been so great nor simultaneous. Not Anaheim Disease. The reasons which have led us to reject as unproven the theory which ascribes the death of the vines to the Anaheim disease are based upon the divergence of the symptoms from those which distinguish that disease as characterized in Bulletin 2 of the Division of Vegetable Pathology of the U. S. Department of Agriculture, entitled " The California Vine Disease," by Newton B. Pierce. This pamphlet must be considered as the highest authority on this disease, as it is almost the only, or at least the most complete and voluminous, publi- cation on the subject. 10 Characteristics of Anaheim Characteristics Shown by Dying Vines Disease. in Santa Clara Valley. Mission more susceptible than Mataro or Zinfandel. 'Page 141 Mataro and Zinfandel have died more generally than the Mission. Vines in shade of trees less rapidly i j Vines near trees have suffered as much affected. 108 | or more than others. j ! Grafting the vines does not save them. ! 138 ! All the recently grafted vineyards are healthy. Cuttings from affected vines which | I There are many instances in which cut- show the disease die as soon as the j tings taken during the last two, three, parent vines. I 152 i and four years from Mataro and Mis- sion vines which are now dead have been planted, or grafted on phyllox- era-resistant stock, and have now resulted in vigorous, healthy vines. Rotting of the roots is a constant | symptom. 52 Roots of most of the injured vines are sound. *The numbers refer to pages in the above-mentioned bulletin. To these contrasts should be added the apparent recovery of Grenache vines, which were badly affected last year and this spring, but which in August were making a vigorous healthy growth. Though Mr. Pierce may not make the statement definitely, the impression left, on reading his publications on the Anaheim disease, is that it is cumulative and progressive and that the attacked vines never recover. These contrasts prove either that the Anaheim disease is not the cause of the death of the Santa Clara vines, or that the characteri- zation of the disease as given in the publication above referred to must be profoundly modified to include the symptoms exhibited by these vines. There is, however, no reason at present to suggest the Anaheim disease if, as seems at least very probable, the causes here outlined are sufficient to account for the observed effects. Practical Lessons. This serious disaster contains two important prac- tical lessons to horticulturists, and especially to vineyardists: First, the necessity of having on hand the means for supplementing a deficient rainfall, even in what are usually considered the non-irrigating districts; and second, the importance of choosing varieties adapted to special locations, soils, and climates. This question of adaptation is particu- larly important to grape-growers who are planting phylloxera-resistant stock, as all the good and thoroughly resistant vines are comparatively limited in their range of adaptability. Wherever new vines are planted in the devastated area it would be extremely unwise to plant any variety which has not well-proved drought-resisting qualities. The resistant vines which have shown the best results so far on the west side of the Santa Clara Valley are Rupestris St. George, Rupestris Martin, and Champini. The last has thriven almost or quite as well as the two 11 Rupestris varieties, but unless it shows marked superiority in some other way the others are to be preferred on account of their superior phylloxera-resistant qualities and the greater ease with which they root. The suggestion that Rupestris St. George is resistant to the Anaheim disease is certainly premature when based upon its behavior in the Santa Clara Valley, in view of the fact that the presence of that disease in the valley is more than doubtful, for even Mr. Pierce, the acknowledged authority on this disease, after making an examination of the afflicted vineyards, says in the "California Fruit-Grower" of July 27, 1901, that he "will not express an opinion at this time as to the presence or absence of the California (Anaheim) vine disease in this district." FREDERIC T. BIOLETTI. E. H. TWIGHT. UNIVERSITY OF CALIFORNIA PUBLICATIONS COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION NEW METHODS OF GRAFTING AND BUDDING VINES BY E. H. TWIGHT. 1 1 HHC Riparia Gloire de Montpellier. Rupestris St. George. Solonis. BULLETIN NO. 146 BERKELEY: THE UNIVERSITY PRESS November, 1902 BENJAMIN IDE WHEELER, Ph.D., LL.D., President of the University. EXPERIMENT STATION STAFF. E. W. HILGARD, Ph.D., LL.D., Director and Chemist. E. J. WICKSON, M.A., Horticulturist, and Superintendent of Central Station Grounds. W. A. SETCHELL, Ph.D., Botanist. R. H. LOUGHRIDGE, Ph.D., Agricultural Geologist and Soil Physicist. (Soils and Alkali.) C. W. WOODWORTH, M.S., Entomologist. *M. E. JAFFA, M.S., Assistant Chemist. (Foods, Fertilizers.) G. W. SHAW, M.A., Ph.D., Assistant Chemist. (Soils, Beet-Sugar.) GEORGE E. COLBY, M.S., Assistant Chemist. (Fruits, Waters, Insecticides.) LEROY ANDERSON, M.S. A., Animal Industries, San Luis Obispo. A. R. WARD, B.S.A.. D.V.M., Veterinarian, Bacteriologist. E. H. TWIGHT, B.Sc., Diplome E.A.M., Viticulturist. E. W. MAJOR, B.Agr., Dairy Husbandry. A. V. STUBENRAUCH, M.S., Assistant Horticulturist and Superintendent of Sub- * stations. *J. BURTT DAVY, Assistant Botanist. H. M. HALL, M.S., Assistant Botanist. C. A. TRIEBEL, Ph.G., Student Assistant in Agricultural Laboratory. C. A. COLMORE, B.S,, Clerk to the Director. EMIL KELLNER, Foreman of Central Station Grounds. JOHN TOUHY, Patron, , Tulare Substation, Tulare. JULIUS FORRER, Foreman, j R. C. RUST, Patron, ) f >- Foothill Substation, Jackson. JOHN H. BARBER, Foreman,] S. D. MERK, Patron, ) . ' TT , . > Coast Range Substation, Paso Robles. J. H. OOLEY, Workman in charge,] S. N. ANDROUS, Patron,) ( Pomona. T TTT _.. _ > Southern California Substation, < _ J. W. MILLS, Foreman, ] ( Ontario. V. C. RICHARDS, Patron, ) _ m T _ . > Forestry Station, Chico. T. L. BOHLENDER, in charge,] ROY JONES, Patron, ) T TTT n r Forestry Station, Santa Monica. WM. SHUTT, Foreman, J * Absent on leave. The Station publications (REPORTS AND BULLETINS) will be sent to any citizen of the State on application, so long as available. NEW METHODS OF GRAFTING AND BUDDING APPLIED TO THE RE-ESTABLISHMENT OF VINEYARDS WITH AMERICAN VINES. When two branches or stems of closely related plants, growing side by side in a forest, overlap and touch each other, the bark becomes bruised and abraded. In such cases the sap exuding from the alburnum frequently produces a pad or callus by which incorporation or knitting takes place and the parts become one. From this obser- vation the idea of creating artificial wounds to obtain a graft probably originated. Grafting above ground was a common practice in the vineyards of the Romans, and their authors describe them carefully, while they hardly mention the underground graft. But for some reason, until recently most of these grafts tried upon the vines in modern times have failed. In the last ten years persistent efforts and successful experimentation in Europe have brought the discovery of new processes that have been very successful, and their use tends to become widely spread, though a few years ago the best authorities on viticulture condemned them. Green Cleft Graft. This graft is used a great deal in Hungary; it is an ordinary cleft graft made on the green shoots of very young vines. The shoot used as stock is cut between the second and third leaves (A-A) counting from the apex, and one and one-half to two inches above the third leaf. The latter is pinched at B-B. The scion is a similar shoot, the leaves of which are pinched. The ligature used is wool or raffia, and must be removed as soon as it begins to cramp the joint. This graft necessitates the decapitation of the stock, and is exposed to drying; and though used successfully on some vineyards of Hungary, it might not do as well in our drier climate. Horwath Graft. The Horwath graft (Fig. 2) consists in inserting a scion bud in the place of an eye of the stock; it is commonly used on fruit trees, but the excision of the bud on a vine cannot be done in the same way, because of the considerable protuberance existing at each node. The following method was adopted by Horwath : 4 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION, FIG. 1. GREEN CLEFT GRAFT. FIG. 2. HORWATH GRAFT. NEW METHODS OF GRAFTING AND BUDDING. 5 A circular incision, penetrating the whole depth of the bark, is made -inch above and another the same distance below the bud (a, 5) ; then on the right and left of the bud two longitudinal parallel incisions are made, joining the annular incisions. The bud thus prepared (c) should be placed on a shoot of as nearly as possible the same diameter as that from which it was taken. But the indispensable point, which marks the difference between ordinary budding and Professor Hor- wath's method, is that the bud must be placed or inserted in place of another bud on a node. The green shoot to be used as stock having been chosen, and on the latter the bud where the graft is to be made determined, the leaf on that node is removed (c) . Two semi-annular incisions are made (a , &') at the same dis- tances as on the scion, and a single longitudinal cut is made passing through the bark, dividing the petiole in two and joining the annu- lar incisions. Then with the spatula of the grafting knife the bark is lifted on both sides so as to form two flaps, as in ordinary bud- ding. The flaps being open , the scion is inserted (d) , the flaps brought over it and the joint ligated. A fortnight or twenty days after, this is cut off. This graft has given good results, but is a lengthy and delicate operation . Salgues Graft. The Salgues graft (Figs. 3 and 4) consists of fixing on a green shoot of the year an elliptic scion or shield carrying a bud at its cen- Cl I) ter. It is budding, but so FlG 3 modified as to be cohsid- SALGUES GRAFT. (Original.} ered a new method; the grafts obtained are perfect and the joints invisible except for a slight swelling. 6 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. On any internode of the shoot to be grafted a longitudinal incision (Fig. 3, a) is made with the grafting knife, penetrating the whole depth of the bark and about the length of the shield; with the haft of the grafting knife the bark is raised on both sides of the slit; the shoot is then bent inwards and the lips of the slit open easily (Fig. 3, &) . The scion bud is inserted and the shoot is left to spring up into its former position. The scion bud is then compressed by the bark, and the operation is completed by tying. The ligature should be removed a fortnight or twenty days afterwards. , a b c FIG. 4. SALGUES GRAFT. VIEWS OF SCION BUD () SIDE, (&) FRONT, (c) BACK. In order that the Salgues graft may be a success, it is necessary, first, that the stock should be in full sap, so that the lips of the slit may be easily raised; secondly, that the scion bud should be carefully selected. When a green shoot is cut longitudinally on its entire length, different colorations may be noticed along the section; towards the apex the shoot has not yet begun to lignify, and the section is almost uniformly green in color, only slightly deeper above and below each node. The diaphragm of these can only be detected at the second or NEW METHODS OF GRAFTING AND BUDDING. third node (counting from the top) by a slightly lighter color. Downwards the diaphragm becomes more distinct; finally, still lower, the pith begins to be indicated by a whitish tint; the scion bud should be taken only from the buds in which the diaphragm is already well apparent, but on the part of the shoot where the white pith is not noticeable. Each shoot will thus give two or three good eyes. In practice, when one tries to bend a young vine- shoot there is no resistance at the top; then lower down it resists, and still lower down it does not bend but breaks. When the fingers can easily bend the shoot and feel a slight resistance, one is sure that the bud in that region, together with the one above and the one below, are suitable for budding. It is necessary to tie the grafted shoots to a stake, as they are thus better protected and do not dry out as easily as when close to the ground. This graft is simple, gives perfect union, and is getting to be very generally used. It is of great value in reestablish- ing vineyards on resistant stock. The Salgues graft may be performed on mother stocks of American vines through the summer as shoots develop; one can bud sixteen inches apart on the canes with the object of obtaining grafted cut- tings for the next season. We have seen contracts given out for this work for $6 a 1000 knitted grafts. Besson Graft. As stated above, the Salgues scion-bud is grafted on the internode of the shoot. The Besson graft (Fig. 5) like that of Horwath, is inserted on the node itself; but while the method of the Hungarian viticult- urist is a true budding, that of Besson is an inlaying. This graft is made in spring, at the same time as the ordinary bench graft. A special pair of shears is used, with curved blades perpen- dicular to the handle; it cuts and lifts the bud, the same operation being made on the stock and scion canes. The lateral portion detached must be a little under one-half of the thickness of the shoot; the cut is regularly curved and concave, and about one inch long. FIG. 5. BESSON GRAFT. (Rev. de Fit., 1894. 8 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. On the stock, the second eye, counting from the top of the cutting, is cut out; while for the scion any one of the eyes on the cane is used. The scion-bud fits perfectly, as it is the same blade that makes the two cuts. The cuttings to be grafted should be sixteen inches in length their top being limited by a bud cut half-way through. The graft is tied with raffia, as in other bench grafts. So far, this graft tried on green shoots has not been a success, but on the ripe canes the results have been very good and the quality of the knitting is specially good. Clarac Graft. In the Clarac graft (Figs. 6 and 7) , as in the Besson graft, a bud is substituted for another bud, but the process differs in many points. To prepare the stock an incision is made an eighth of an inch above a bud (Fig. 6, a) and the incision is continued in a straight section parallel to the axis of the cane, penetrating one-third of the diameter; the cut is stopped when the length is a little over the width of the blade FIG. 6. CLARAC GRAFT. under the the base of the bud (Fig. 6, &). The blade is removed, laid flat on the cane immediately under the base of the bud, in order to indicate by the width of the blade the point where the new trans- verse and oblique incision is to be made, to prevent the first section from spreading and to make a strong notch for the scion to rest upon (Fig. 6, c). The scion-bud is obtained in the same way, placed on the stock and tied. NEW METHODS OF GRAFTING AND BUDDING. Another way of making the Clarac graft consists in not removing the bud on the stock, only the longitudinal cut being made. The scion-bud is made in the same way but with a longer bevel; it is inserted in the slit prepared on the stock and tied. The bud left on the stock constitutes a sap drawer, which facilitates the knitting of the scion -bud. When knitting has taken place the stock bud is removed. CLARAC GRAFT: METHOD WHERE BUD IS LEFT ON STOCK. (E. de Vit., 1894.) The second method is more rapid. In both cases the ligature must be cut away three weeks after being made. Both methods have been successful. 10 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Massabie Graft. This is practically the same as the Besson graft, but the scion-bud is cut with a special pair of shears. Vouzou Graft. The Vouzou graft (Figs. 8 and 9) is a Salgues graft made with an old scion-bud. On a smooth part of the stock above ground a T-shaped incision is made through the bark, and the sides are raised with the haft of the grafting knife. The scion is taken from a cane of the previous year's growth before the eyes start to burst in the spring, and preserved in sand until the time of grafting. The bud should be well constituted and healthy, but need not be at a particular state of development, as in the Salgues graft. The scion- bud is cut out as is done for fruit trees, but under the eye a thickness of wood is left reaching to the pith ; and even a little of the latter may be left. This will give a scion about one inch long, with the inside section nearly flat. The bud is inserted and tied in the usual way. To insure knitting the shoots of the stock must be pinched short; the tie is cut one month after. This graft may be made during the whole period during which the sap is circulating, and when the bark is detachable from the wood. The Vouzou graft has been very successful; 75 to 85 per cent, of "takes" have commonly been ob- tained, and in one instance the suc- cess of 95 per cent was publicly demonstrated. It is a simple graft and gives a perfect union. In case of failure it is easy to repeat it the same season. FIG. 8. AN ORDINARY METHOD OF BUD- DING ON A VINE CANE. (a) SLIT BEFORE BUD IS INSERTED, (&) SAME AFTER INSERTION OF SCION- BUD. (Original.) NEW METHODS OF GRAFTING AND BUDDING. 11 FIG. 9. SAME AS 8 MAGNIFIED. THE TYING OF BUDS HAS BEEN MADE WITHOUT USING THE FOIL. (Rev. de Fit., 1895.) MEANS OF INSURING THE SUCCESS OF HERBACEOUS GRAFTS. Selection of shoots bearing buds for scions. We should, always choose branches growing from eyes which would have normally remained dormant till the following season, in preference to branches growing from buds bursting out normally. Shoots of medium or rather small diameter are to be preferred. These shoots will furnish the scion-buds which are to be grafted on the old wood. The diameter of the shoot from which the scion-bud is cut must always be a little smaller than the diameter of those upon which it is to be grafted. The best shoot is that developed in the shade; branches exposed to direct sunlight must always be rejected; the shoot should be light green in color, but not yellow. The petioles of the leaves of the shoot should be of a whitish-green color, even a little pinkish, slightly transparent at the point of junc- tion with the limb. Shoots bearing leaves with deep green or reddish petioles should be rejected. The eyes of the extremity and base of the shoots, together with those placed at the base of the leaves having a very slender or very long petiole should not be used. 12 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Preparation of Scion-Buds. The whole of the petiole and part of the limb of the Jeaf should be left when the leaf is pinched; if the petiole is cut shorter the bud dries out. The same bud may be made with sap-wood or with half sap-wood, the latter is by far the best. Scion with Sap-wood. (a, &, c, Fig. 9; , b, c, Fig. 4). To cut out the shields, the shoot is held with the left hand, the first finger being under the bud; the cut is begun with the base the grafting knife half an inch below the bud; and while cutting, the knife blade is drawn in such a way that the end of the grafting knife will corre- spond with the end of the section, half an inch below the bud, when finished. This shield will be about li inches long, and as it will have a chipped edge, it is advisable to smooth it down, which will reduce it to about one inch. The scion-bud is then rather thick in the center and the ends are pointed bevels. The sap-wood of the shield does not knit, therefore it is advisable to diminish its surface. Scion with Half Sap-wood. This is far superior to the above. The cut is started in the same way (a, Fig. 10), but the knife is drawn parallel to the axis of the cane, as in 6, Fig. 6. Drawing the blade out the transversal section bb (Fig. 10) is made cutting through the bark only. The bud is seized between the thumb and first finger of the right hand and lifted (c) and pulled back (d) . As the transverse cut only FIG. 10. PREPARING A HALF SAP-WOOD SCION -BUD. goes through the bark, in lifting the bud a tongue of sap-wood remains attached to the cane (d) and adheres to the scion-bud. When we lift this up it breaks off level with the bud, leaving a two-pronged fork (e, Fig. 10). If the fork is not formed, the bud should be NEW METHODS OF GRAFTING AND BUDDING. 13 rejected, as it is not ripe enough. It is hard to explain this mode of operating, but it is really easy in practice. Making the Slit on the Stock. On one- or two-year-old canes, the slit should be made on the rounded part where the bark is thicker and will protect better against desication. However, if the scion-bud has a little sap-wood attached, it is better to place it on the flat side. On old wood the bark is so thin that it is almost impossible to lift it off. Ligatures. The best are made out of lead or tinfoil tied with raffia or cotton. The foil is cut into pieces three-quarters to one inch wide and two to three inches long. Arrangement of Mother Stock. All shoots of American stock may be readily budded; that is to say a person can place on a vigorous cane from ten to twenty buds and obtain the next season from one vigorous mother vine 100 to 150 grafted cuttings. Long experience has shown that to obtain these results it is necessary to arrange the stocks in the following manner: Stakes about six or eight feet high are erected ten to fifteen feet apart. As soon as the shoots of the mother stock are about twenty inches in length, eight to twelve are preserved and the balance dis- budded. The shoots are tied up in V-shape as soon as hard enough, all auxiliary buds and tendrils being removed; this is repeated three times in the season. The even numbered shoots are tied up on one side and those of odd numbers on the other; this facilitates the bud- ding and collecting of the knitted cuttings; twice the amount of wood fit to be budded is obtained in this way. On an experimental plot one hundred 4-year-old Riparia were trellised and as many left without trellising. The first gave an average of 175 feet, the latter 75 feet of wood suitable for budding. Gathering and Keeping the Budded Cuttings. We should wait until the leaves have fallen off before gathering the cuttings; they should be cut off on the spot; the whole cane should not be cut off and then the cuttings be removed later, as they are apt to be bruised if treated thus. As the cuttings are gathered, the eyes of the stock are removed, excising them with a grafting knife as closely as possible; those where the buds have missed may be kept to be bench-grafted the next spring. The good ones are placed in cases, in layers separated by fresh moss or moist straw. A lid is placed on the box and the cases are placed in a closed, dry, frost-proof room, and kept until planted. Then the boxes are taken out to the nursery, the cuttings taken out one by one, and their upper end freshened with a grafting knife (not shears), three-fourths to one inch being removed at each end. The cut end is then coated with tar. UNIVERSITY OF CALIFORNIA PUBLICATIONS. COLLEGE OF AGRICULTURE, AGRICULTURAL EXPERIMENT STATION. RESISTANT VINES AND THEIR HYBRIDS BY E. H. TWIGHT. BULLETIN No. 148. (Berkeley, October, 1902.) SACRAMENTO: w. w. SHANNON, : : : : SUPERINTENDENT STATE PRINTING, 1903. BENJAMIN IDE WHEELER, Ph.D., LL.D., President of the University. EXPERIMENT STATION STAFF. E. W. HILGARD, Ph.D., LL.D., Director and Chemist. E. J. WICKSON, M.A., Horticulturist, and Superintendent of Central Station Grounds. W. A. SETCHELL, Ph.D., Botanist. ELWOOD MEAD, M.S., C.E., Irrigation Engineer . R. H. LOUGHRIDGE, Ph.D., Agricultural Geologist and Soil Physicist. (Soils and Alkali.) C. W. WOODWORTH, M.S., Entomologist. M.JE. JAFFA, M.S., Assistant Chemist. (Foods, Fertilizers.) G. W. SHAW, M.A., Ph.D.. Assistant Chemist. (Soils, Beet-Sugar.) RALPH E. SMITH, B.S., Plant Pathologist. GEORGE E. COLBY, M.S., Assistant Chemist. (Fruits, Waters, Insecticides.) LEROY ANDERSON, M.S.A., Animal Industries, San Luis Obispo. A. R. WARD, B.S.A., D.V.M., Veterinarian, Bacteriologist. E. H. TWIGHT, B.Sc., Diploma E.A.M., Viticultunst. E. W. MAJOR, B.Agr., Dairy Husbandry. A. V. STUBENRAUCH, M.S., Assistant Horticulturist and Superintendent of Substations. WARREN T. CLARKE, Assistant Field Entomologist. H. M. HALL, M.S., Assistant Botanist. C. A. TRIEBEL, Ph.G., Student Assistant in Agricultural Laboratory. C. A. COLMORE, B.S., Clerk to the Director. EMIL KELLNER, Foreman of Central Station Grounds. JOHN TUOHY, Patron, . Tulare Substation, Tulare. JULIUS FOR HER, Foreman, R. C. RUST, Patron, ) J- Foothill Substation, Jackson. JOHN H. BARBER, Foreman, ) S. D. MERK, Patron, ) > Coast Range Substation, Paso Robles. J. H. OOLEY, Workman in charge, ) 8. N. ANDROUS, Patron, ) ( Pomona, J- Southern California Substation, -\ J. W. MILLS, Foreman, ) ( Ontario. V. C. RICHARDS, Patron, ) V Forestry Station, Chico. T. L. BOHLENDER, in charge, ) ROY JONES. Patron, ) } Forestry Station, Santa Monica. WM. SHUTT, Foreman, ) The Station publications (REPORTS AND BULLETINS) will be sent to any citizen of the State on application, so long as available. RESISTANT VINES AND THEIR HYBRIDS. GENERALITIES REGARDING RESISTANT VINES. (Abstract from Bulletin No. 131, by F. T. Bioletti.) The most satisfactory method of combating phylloxera is the use of resistant vines, because it is applicable to all conditions and is the most economical in the end. A resistant vine is one which is capable of keep- ing alive and growing even when phylloxera are living upon its roots. Its resistance depends on two facts: first, that the insects do not increase so rapidly on its roots; and second, that the swellings of diseased tissue caused by the punctures of the insects do not extend deeper than the bark of the rootlets and are sloughed off every year, leaving the roots as healthy as before. The wild vines of the Mississippi States have evolved in company with the phylloxera, and it is naturally among these that we find the most resistant forms. No vine is thoroughly resistant in the sense that phylloxera will not attack it at all; but on the most resistant the damage is so slight as to be imperceptible. The European vine ( Vitis vinifera, L.) is the most susceptible of all, and all the grapes cultivated in California, with a few unimportant exceptions, belong to this species. Between these two extremes we find all degrees of resistance, which is expressed by a series of numbers ranging from 20, indicating the highest possible resistance, to 0, indicating the utmost susceptibility. The following table shows the resistance (according to Viala and Ravaz and other authorities) of some of the best known species and varieties: COMPARATIVE RESISTANCE TO PHYLLOXERA. Species ( Wild Vines). Cultivated Varieties and Hybrids. Vitis rotundifolia _. 19 Gloire de Montpellier (Riparia). 18 Vitis vulpina ( Riparia) 18 Riparia X Rupestris 3309 18 Vitis rupestris _ 18 Rupestris Martin 18 Vitis Berlandieri _ 17 Rupestris St. George 16 Vitis sesti valis .._ 16 Riparia X Solonis 1616 16 Vitis labrusca 5 Solonis. 14 Vitis Californica 4 Lenoir _ ..12 Vitis vinifera Isabella.. ....J 5 The degree of resistance necessary for the production of good crops varies with the character of the soil. The resistance expressed by the numbers 16 to 20 is sufficient for all soils. A resistance of 14 or 15 is sufficient in sandy and moist, rich soils, where the vine can readily replace the rootlets as fast as they are destroyed. Fairly successful vineyards have been established exceptionally with vines having a 4 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. resistance of less than 14, but as the vines become old the lack of resistance is generally shown by a weakening of the vine and a falling off of the crop. Many vineyards in the south of France grafted on Lenoir which formerly bore well, have now to be doctored with injec- tions of bisulfid. For this reason it is advisable to reject all vines with a resistance of 13 or under, especially as v^ines with greater resistance can now be obtained for practically all conditions. Resistant vines are of two kinds: (a) those which are grown for the grapes they produce, and (b) those which are useful only as stocks on which to graft the non-resistant varieties. The former are called " direct producers" the latter, " resistant stocks." (a) Direct Producers. When the phylloxera commenced to destroy the vineyards of Europe, the natural attempt was made to replace them with the varieties of vines which had proved successful in the United States, where the insect was endemic. These varieties, however, all proved unsatisfactory. Some, like the Concord and the Catawba, were insufficiently resistant, and although they could be grown where the severe cold of winter impeded the prolificness of the phylloxera, they quickly succumbed in the milder grape-growing sections of Europe.* Most of them were poor bearers compared with the prolific European vines, and finally the character of their fruit differed so widely from what Europeans were accustomed to that there was little sale for the fruit, and the wine could compete with only the very poorest quality of Vinifera wines, and brought a very inferior price. A few of the varieties introduced during that first period are still grown to a limited extent in France, chiefly the Othello and the Lenoir. They are being gradually abandoned, however, as their crops are unsatisfactory, and in many localities can be maintained only by the aid of injections of bisulfid. For some years the search for a suitable direct producer was almost abandoned by practical men, the use of resistant stocks having been so fully successful. Lately, however, renewed efforts have been made and several new direct producers are being advocated and planted to some extent. The merit of these new varieties, however, is chiefly their resistance to Peronospora and Black Rot. Phylloxera-resistance is con- sidered of much less importance by their most ardent advocates, and indeed the advice is given to graft some of the best of these direct pro- ducers upon phylloxera-resistant stock. The main importance of these facts to California grape-growers is that they hold out hopes of perma- nent prosperity for the wine-making industry here, where, owing to the dryness of the climate, there is no likelihood of trouble from these serious fungous diseases of the grape, which threaten to make the grow- ing of Vinifera varieties impossible in many parts of Europe. *\n California, these and other Labrusca varieties and hybrids resist very little longer than Vinifera vines. I RESISTANT VINES. 5 (b) Resistant Stocks. Though high resistance to phylloxera is essential in a grafting stock, there are other characteristics equally necessary. The Rotundifolia (Scuppernong), which has the highest resistance of any vine, is useless as a stock on account of the impossibility of grafting it with any Vinifera variety. This is due to a lack of affinity, which means a lack of similarity in structure and composition between the tissues of the stock and those of the scion. This lack, in extreme cases, results in an imperfect and temporary union, but when not excessive, only in a slight decrease of vigor. The affinity is not perfect between Vinifera varieties and any resistant stock, but in the case of Riparia and Rupestris is generally sufficient to insure permanence to the union, and the slight decrease of vigor consequent often results in an increase of fruitfulness. It is for this reason that certain varieties when grafted on resistant stocks, especially on Riparia, often bear larger crops than when grown on their own roots. Not all varieties of Vinifera have the same affinity for the same stock. For this reason it is desirable to be cautious about making new or untried grafting combinations on a large scale. Some varieties, such as Carignan, Petite Sirah, Clairette, and Cabernet Sauvignon, do excellently on all stocks; while others, such as Mondeuse and Gam ay, do not make a very good union with any of the thoroughly resistant stocks. The Petit Bouschet and Cinsaut make very poor unions with any variety of Riparia, but do fairly well on Rupestris St. George. The Pinot Noir makes a vigorous growth upon Rupestris St. George, but bears much more prolifically upon Riparia Gloire. Selection. A very serious defect of many resistant stocks is a slender habit of growth. This is true of most of the vines found growing wild, and cuttings from such vines make poor grafting stock for the stout Vinifera varieties, which will produce a trunk four inches in diameter while the stock is growing only two inches. This is particularly true of the wild Riparias. For this reason great care has been exercised in selecting the stronger-growing forms, and at present we have selected Riparia varieties which almost equal Vinifera in the stoutness of their trunks. The best of these are the Riparia Gloire de Montpellier and the Riparia Grande Glabre, the first of which has given the best results in California. RESISTANT VINES AND THEIR HYBRIDS. BY E. H. TWIGHT. If we study the conditions affecting the adaptation of resistant vines, we see that the amount of lime contained in the soil, the degree of com- pactness, the moisture, and the fertility of the land are the most important factors. The proportion of lime in the soil has been, in many countries and particularly in France, the greatest drawback in 6 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. re-establishing vineyards on resistant stock. Happily, in California we do not have to contend with that part of the problem, as few soils con- tain enough lime to affect even the Riparias and Rupestris, that are among the first to suffer from excess of carbonate of lime. The compactness of the soil, generally due to the large proportion of clay it contains, is an obstacle to the good growth of many varieties of resistant stock; the roots do not penetrate easily, the ground is cold and often wet, and under such conditions the Rupestris and Riparia, for instance, do poorly. On the contrary, the Lenoir, Champini, Riparia X Rupestris No. 3306 and 101 14 will do well in such locations, and the hybrids of Solonis X Cordifolia X Rupestris will do still better. The last-mentioned have a higher resistance to phylloxera than Lenoir and Champini. If we examine the probable cause for the special adaptation to heavy soils, we see that whereas the Riparia and Rupes- tris have light, thin, hard roots very much ramified; on the contrary the varieties adapted to such soils have strong, fleshy roots, less ramified, with a heavier hair system on the rootlets. When in excess, the moisture in the soil affects the vine by checking the growth of the root system. Plants growing in a very moist place may have a vigorous aerial growth, but the root system is generally weak; such a plant will suffer greatly if for some reason the supply of moisture should fall below the average. The root system in a dry exposure will always be much more vigorous, as the plant has to send its roots lower down to find the water it needs. On the other hand, a moist soil will help a vine in its fight against phylloxera, and under such conditions some stocks, though inferior in absolute resistance, may do fairly well. As a general rule, the Solonis and its hybrids are very good in wet soils. The fertility of the soil is a condition of adaptation that we must not overlook: A Riparia or a Solonis will turn yellow and look sick in a soil where a Rupestris would do fairly well. This does not mean that a Rupestris will not do better in a good soil than in a poor one, but simply that it is more rustic in its adaptation. VARIETIES OF RESISTANT STOCK. We give below the adaptation of the principal varieties of resistant vines used as grafting stock or as parents in the making of hybrids. (Riparia, Rupestris, Candicans, Cordifolia, Monticola, Arizonica, Cali- fornica, Berlandieri.) Vitis riparia. The V. riparia (see title-page) is very resistant to phylloxera (18).* The grafts made on this stock are fructiferous, vigorous, and advanced in maturity. All varieties root readily from *Resistance to the phylloxera is indicated by figures on the scale of 20 points. RESISTANT VINES. 7 cuttings and from grafted cuttings; they also take easily from field grafts. This stock has often been over-boomed, and planted in many localities where it could never grow; and from these failures some people have jumped to the conclusion that the stock is of no value. But when we consider that in France alone, seventy-two per cent of the vineyards that have been replanted are on Riparia roots, we readily see that the failures must be due to the ignorance of the conditions of adaptation. Riparias do not grow well in dry locations; they must have a good loamy soil, the best being clayey-siliceous alluvions; a deep, cool, fertile PLATE 1. VITIS RUPESTRIS ST. GEORGE. Showing on the right the natural fold of the leaves along the mid rib, and on the left the bracket-shaped petiolar sinus. soil, not too wet. The two varieties mostly used are the Riparia Gloire de Montpellier and the Riparia Grande Glabre. Vitis rupestris. This vine, shown in Plate 1 , is found in its wild state in open places along hillsides and ravines in the arid eastern part of the region, growing in gravels and in decomposed rocks. From this natural 8 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. habitat we may see that it will be well adapted to light gravelly soil?, hillsides, and sandy soils. It is very resistant to phylloxera (16-18). The Rupestris vines have a larger trunk than the Riparias and show, after grafting, less difference between the scion and stock. The cuttings root easily, but not quite as well as those of Riparias; the rooting can be aided by scratching the bark of the lower part of the cutting on a short-tooth iron comb. The returns in bench-grafting are about the same as those obtained with Riparia. As the Rupestris cuttings sucker very much, it is of great importance to suppress carefully the eyes on PLATE 2. VITIS CANDICANS. MUSTANG GRAPE. Showing the entire or lobed leaves with the limb convex on the upper face. Three of the leaves are turned over, showing the very thick, white felt on the under face of the leaves. the stock when bench-grafting. Of the two varieties that are mostly used, the Rupestris Martin is possibly a little better adapted to dry locations. The Rupestris St. George, though well adapted to gravelly hillsides and light soils, has proved also, in the last few years, to be a vigorous grower, even in lands where the water-table is close to the surface several months in the year. (Letter from Prof. L. Ravaz.) Vitis candicans. The V. candicans, or Mustang grape (Plate 2), found in its wild state in Texas and Arkansas, grows generally on bottom RESISTANT VINES. 9 lands and along rivers, but it is also found in very dry locations; in these, however, its growth is not as vigorous. It does best in alluvial soils, but its large roots enable it to grow well in heavy clays. This variety is hard to grow from cuttings, but is very valuable in hybridization. Vitis cordifolia. This vine is adapted to the same class of soils as the V. riparia; it is very highly resistant to phylloxera, and does fairly well in heavy soils; it has been also used to great advantage in creating hybrids. PLATE 3. V. ARIZONICA. Vitis arizonica. This vine (Plate 3) is found mostly in Arizona and New Mexico, while numerous hybrids of Arizonica X Californica exist in the region where both varieties grow wild. It grows well from cuttings, is nearly as resistant as Rupestris, and ought to be studied carefully. In adaptation it would hold a place between the Riparia and the Rupestris. 10 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Vitis monticola. This vine has only a limited range of distribution in Texas, where it is found on lands similar to those where the Rupes- tris grows, but containing generally a high percentage of lime. It comes next to the Berlandieri as a resistant to chlorose, which is caused by excess of lime in the soil. This stock is a very good element in hybrid- izing, and may turn out to be very valuable as a direct grafting stock. Vitis calif ornica. The wild native vine of California; it has a resistance to phylloxera too low to be of much use. Vitis Berlandieri. This vine is found in Texas, New Mexico, and Mexico, growing on limestone ridges, where it resists excessive drought and heat. The quality of resistance to lime would not be of much interest in California, but it may prove to be a very valuable stock in heavy, dry soils, as probably its large fleshy roots will allow it to penetrate readily. Though the Berlandieri does not grow well from cuttings, its hybrids have not that drawback. From these few remarks on the principal resistant stocks we may see that the range of adaptation of each variety is rather narrow. This observation led the nurserymen and the experiment stations in the countries mostly interested, to try to obtain, by hybridizing, new varieties having a wider range of adaptation. This has been done with two different objects in view. Some simply crossed the American resistant varieties to obtain new grafting stocks having a larger range of adaptation; we will call these Americo X American hybrids. Others tried to cross the American resistant stocks with the Vinifera-producing varieties, to obtain a resistant direct producer; we will call these Vinifera X Americans. So far the latter have only succeeded in making some good grafting stocks, the bearing qualities of the Vinifera not being transmitted. AMERIGO X AMERICAN HYBRIDS. Mr. Munson, in the United States, and a great number of scientists in Europe (Couderc, Millardet, Grasset, Foex, Ravaz) have created a large number of new hybrids, some of the most promising of which we will review. Riparia X Rupestris. This group is probably one of the most inter- esting. Among the varieties selected as the best at present we find NOB. 3306 and 3309 of Couderc and No. 101 U of Millardet. They are very resistant to phylloxera, root easily from cuttings, and give a high percentage of good grafts. The trunk increases rapidly in size, so that there is little difference between stock and scion; the fructification after grafting is good and regular. The range of adaptation is a combination RESISTANT VINES AND HYBRIDS. 11 of that of Riparia and of Rupestris; Nos. 3306 and 101 U being also able to do well in soils a good deal more compact in nature than those suitable for either of the parents; No. 3309 stands drought well. Solonis X Riparia. These hybrids are well known for the heavy- bearing character they communicate to their grafts. The affinity is very good and they are particularly well adapted to wet lands. While adapted to the same soil-conditions mentioned above for the Solonis, they have a much higher resistance to phylloxera than the latter. The best known are Nos. 1615 and 1616 (Couderc). Solonis X Cordifolia X Rupestris. These have great vigor, which they hold from the Cordifolia X Rupestris, while they take some of the characters of the Solonis in moist locations. They have proved very valuable in heavy moist clays. No. 202* of Millardet and Grasset is among the best. Riparia X Cordifolia X Rupestris (No. 106 8 ). Is very similar to the last group regarding its vigor, but is adapted more particularly to very arid locations, where it has proved superior even to the Rupestris Martin. It will probably be of great value in some of our adobe lands. Berlandieri X Riparias. These hybrids have been studied in France, mainly to create a stock having the resistance of the Berlandieri to chlorose, and the easy rooting of the Riparias. Some of the selections have given very satisfactory results (157, 420, 34E). The Berlandieri hybrids are very productive after they have been grafted. The roots are very strong and both surface and deep roots are abundant; as we said before, this hybrid may prove to be very valuable in stiff, dry soils. VINIFERA X AMERICAN HYBRIDS. Lenoir. Though the question of the origin of the Lenoir is not very well settled, it probably comes in this group of Vinifera X American. The Lenoir has a great affinity for the Viniferas, so that when grafted in the field it gives very good results. It does not root as well from cuttings and does not bench-graft as well as the Riparias and Rupestris, but still gives satisfactory results. The resistance to phylloxera is not high (12-13), which is too low unless it is planted in a soil perfectly adapted to its growth. In rich soils, fertile, and with plenty of moisture, it does very well, but these are also good Riparia soils. When the soil becomes compact, then the Lenoir would do better than the Riparia. But for these heavy lands we have to-day such varieties as the Solonis X Cordifolia X Rupestris, the Riparia X Cordifolia X Rupestris, the Riparia X Rupestris 101 u , which are far superior to the Lenoir in resistance, and ought therefore to receive the preference. 12 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Mourvedre X Rupestris or Mataro X Rupestris is a very fine selection of Vinifera X American; the 1202 grows well in all soils from a chalky land to a deep alluvial one. It has been found quite resistant to phylloxera, and particularly well adapted to heavy clay soils. Bourrisquou X Rupestris and Carignane X Rupestris have also a large range of adaptation, but are specially adapted to dry locations. Aramon X Rupestris (1 and 2) are found to do splendidly in clay soils of medium fertility and in soils underlaid with clay. We have a great many of these soils in California, and this stock may prove to be of great value. The roots are superficial, like those of the Riparias, but they are large and fleshy. MUNSON HYBRIDS. Mr. Munson has created, in recent years, a great many hybrids of Americo X Americans and of Vinifera X Americans; some of these are quite promising, but the local results that have been published at different times can not be taken as final proof of their value. We have not yet sufficient data to give personal observations on these, but will give the opinion of Professors Viala and Ravaz, the French viticultural authorities, on some of the Munson resistant stocks. Vitis champini (Candicans X Rupestris). Can be divided in two groups: the glabrous and the tomentose. The glabrous group has a resistance of 14, the tomentose of 12. They are harder to grow from cuttings than the Rupestris, but have the advantage of being good growers in heavy clays and of having large wood. Their low resistance is, however, a grave objection, especially when we have some varieties that do just as well in the same locations and which are much more resistant. Candicans X Monticola (Gwyn, Sanford, Belton). The latter is prob- ably the best; it has a resistance of 16, is very vigorous, has a large trunk, does well in compact soils, and has large wood, but does not grow well from cuttings. Novo-Mexicana. This is probably a Candicans X Riparia X Rupes- tris. The Solonis, Moobetie, Hutchison, and Doaniana are some of the varieties of this group. They are adapted to Solonis soils; that is, rich, with plenty of moisture. They do well in lands that are rather wet and salty (alkali). They grow well from cuttings and have good-sized wood. The resistance to phylloxera is not first class, but is sufficient in soils well adapted to them. In lands not well adapted, they suc- cumb rapidly to the attacks of the insect. The Hutchison is more vigorous and resistant; the Solonis and Doaniana less so. RESISTANT VINES AND HYBRIDS. 13 RESPECTIVE VALUE OF AMERIGO X AMERICANS AND VINIFERA x AMERICANS. We have seen that in both of these groups of hybrids we may find some varieties that are well adapted to our special conditions; in both, we find a good resistance to phylloxera in the selected stock. Which of these should we plant in our vineyards? It may be said in a general way that the Americo X American hybrids, as well as the ordinary American grafting stocks, make the Vinifera scions that are grafted on them bear more heavily than they would if they were on their own roots. They come into full bearing earlier, and generally the fruit will ripen a few days earlier. But the variety of Vinifera grafted on these roots does not reproduce exactly the type it represents when on its own roots: the grapes may be larger, but there is a slight difference in the flavor and the per cent of sugar. The Vinifera vines grafted on Vinifera X American hybrids retain better their original qualities and have a better affinity between stock and scion. The heavy bearing of the vines grafted on Americans or on Americo X American will exhaust the land sooner; so that fertilizing will have to be resorted to earlier, and it is a known fact that heavy fertilization affects the quality of the grapes. From these remarks we may conclude that the American resistant stock and their hybrids will probably be favored by those who look to quantity more than to quality; while for the fancy wine grapes and the better grades of table and raisin grapes the Vinifera X American resistant stock will be chosen. The choice between the two groups is mainly an economic question. A warning must be given regarding the selection of the stock. We find hundreds of thousands of hybrids of each kind, but only very few have been carefully selected. Because the Riparia X Rupestris 3306 or 3309 are good, it is by no means a reason for any " Riparia X Rupestris" to be equally good. The number of the selection is as important, and in fact more important, than the name of the stock. UNIVERSITY OF CALIFORNIA PUBLICATIONS. COLLEGE OF AGRICULTURE. AGRICULTURAL EXPERIMENT STATION. OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY, CALIFORNIA. BY 0. BUTLER. BULLETIN No. 168. (Berkeley, Cal., May, 1905.) SACRAMENTO: w. w. SHANNON, : : : SUPERINTENDENT OF STATE PRINTING. 1905. BENJAMIN IDE WHEELER, Ph.D., LL.D., President of the University. EXPERIMENT STATION STAFF. E. W. HILGARD, Ph.D., LL.D., Director and Chemist. E. J. WICKSON, M.A., Horticulturist. W. A. SETCHELL, Ph.D., Botanist. ELWOOD MEAD, M.S., C.E., Irrigation Engineer. C. W. WOODWORTH, M.S., Entomologist. R. H. LOUGHRIDGE, Ph.D., Agricultural Geologist and Soil Physicist. (Soils and Alkali.) M. E. JAFFA, M.S., Assistant Chemist. (Foods, Nutrition.) G. W. SHAW, M.A., Ph.D., Assistant Chemist. (Starches, Oils, Beet-Sugar.) GEORGE E. COLBY, M.S., Assistant Chemist. (Fruits, Waters, Insecticides.) RALPH E. SMITH, B.S., Plant Pathologist. A. R. WARD, B.S.A., D.V.M., Veterinarian, Bacteriologist. E. W. MAJOR, B.Agr., Animal Industry. A. V. STUBENRAUCH, M.S., Assistant Horticulturist, in charge of Substations. E. H. TWIGHT, B.Sc., Diplom6 E.A.M., Viticulturist. F. T. BIOLETTI, M.S., Viticulturist. WARREN T. CLARKE, B.S., Assistant Field Entomologist. H. M. HALL, M.S., Assistant Botanist. H. J. QUAYLE, A.B., Assistant Entomologist. GEORGE ROBERTS, M.S., Assistant Chemist, in charge Fertilizer Control. C. M. HARING, D.V.M., Assistant Veterinarian and Bacteriologist. 0. A. COLMORE, B.S., Clerk to the Director. R. E. MANSELL, Foreman of Central Station Grounds. JOHN TUOHY, Patron, . Tulare Substation, Tulare. JULIUS FORRER, Foreman, ' J. E. McCOMAS, Patron, Pomona, -^ J. W. MILLS, Superintendent, Pomona, ^ Southern California Substation, In charge Cooperation Experiments of southern California, JOHN H. BARBER, Assistant Superintendent, Ontario, J. W. ROPER, Patron, HENRY WIGHTMAN, In charge ROY JONES, Patron, y University Forestry Station, Chico. WM. SHUTT, Foreman, Universit y Forestr y Station ' H. O. WOODWORTH, M.S., Foreman of Poultry Station, Petaluma. The Station publications (REPORTS AND BULLETINS), so long as avail- able, will be sent to any citizen of the State on application. CONTENTS. THE RED-LEAF DISEASE... DESCRIPTION OF THE DISEASE AND ITS RELATIONSHIPS 6 Effect of the disease on the leaves 6 Effect of the disease on the fruit 8 Effect of the disease on the shoots , 9 The relationships of the Red-leaf disease 9 Resemblance between the Red-leaf disease and the Folletage_. 9 Resemblance between the Rougeot and the Red-leaf disease 10 Resemblance between the Red-leaf disease and the California (or Anaheim) vine disease 10 RESULTS OF WINTER AND SUMMER SPRAYING EXPERIMENTS... 11 Details of the work at the South Sonoma Experiment Plot 13 THE GRAPE-SHRIVEL .. 18 Description ... 18 Effect of the disease on the grapes 18 Effect of the disease on the leaves 19 Internal appearance of the shoots, spurs, arms, and body of vines 20 Generalities regarding the work at the East Sonoma Experiment Plot 21 Cause of the Grape-Shrivel 23 ROOT-ROT __ .-24 OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY, CALIFORNIA. BY O. BUTLER. Introduction. In 1903 the Viticultural Department of the College of Agriculture of the University of California took up the study of a disease that, for a few seasons, had been observed in Sonoma County and was beginning to cause some anxiety among the vine- yardists. After an inspection of the vineyards of Sonoma County from Santa Rosa to Cloverdale, including those of Alexander Valley and Dry Creek, we found that the "Red-leaf disease," as the malady was called, was sufficiently widespread to require special attention. The "Red-leaf disease" was, at that time, associated by many per- sons with the Anaheim disease, and by some with Anthracnose. The first theory was set aside h priori, on account of the difference in the effect on the canes and grapes, and also on account of the lack of virulence of the disease when attacking the Mission vines.* The suggestion that it might be Anthracnose was easily set aside, as the markings of the disease on leaves, canes, and berries are of an entirely different character; it is very doubtful that the true Anthracnosef has ever been found in a vineyard of California. On my return from this trip of investigation, I passed through Xapa Valley to com- pare the " Red-leaf disease" with a malady of similar character that had caused damage in some sections, and, after a consultation with Dr. E. W. Hilgard, it was decided to start a methodic study of the "Red-leaf disease," and Mr. O. Butler was appointed to carry out the investigations. This bulletin gives the results of his preliminary obser- vations. During the same season arrangements were made with several vineyardists to establish experiment plots on their land during the following year. While investigating the "Red-leaf disease," Mr. Butler found that a number of mala- dies, either parasitic or physiological, w r ere responsible in a measure for the weakness or dying of the vines. Among these affections Phylloxera, Root-rot, Mildew, lack of affinity between scion and stock, lack of adaptation of stock to soil, mechanical injuries, Erinose, and Black-knot are quite prevalent in Sonoma County, as well as in most vineyard districts of California. A description of some of these will be given in separate bulletins, while others have been already discussed in former publications: Report of Viticultural Commission, 1893; Bulletins Nos. 127, 131, 146, 148, of the Agricultural Experiment Station of the University of California.:}: Mr. Butler's observations seem to show that the cause of the Red-leaf disease is not parasitic, but that it is more probably due to soil and atmospheric conditions. These observations will be kept up during the coming season, and a careful examination of the subsoil and moisture-contents of the experimental plots will be made through the grow- ing season, so that definite conclusions may be drawn. E. H. TWIGHT. THE RED-LEAF DISEASE. In 1903, the attention of the public was aroused by the alarming notices published in the Sonoma County papers about a new and mys- terious malady, which was unanimously denominated Red-leaf disease. Opinions were freely aired as to the nature of the disease, but the * N. B. Pierce, Bulletin No. 2, Div. Veg. Path., U. S. Dept Agr., page 7. fSphaceloma ampelinum. JAlso, in "American Vines," by P. Viala and Ravaz ; translated from the French by R Dubois and E. H. Tvvight. 6 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. disease itself was not described. The reader was left to conjecture, from the name the grape-growers were agreed upon giving to it, that a red leaf was its main characteristic. Beyond this, however, the grape- growers did not entirely agree ; the term red leaf is indefinite enough to allow of a wide individualistic interpretation, and the grower who had vines suffering, or dying, from a cause undiscoverable to him, and showing a foliage tinted, perchance, here and there with red, was inclined to call the trouble from which his vines were suffering the Red-leaf disease. This diversity of opinion was at first rather confusing, and was more a hindrance than a help in furthering the investigations. In fact, of the three vineyards kept constantly under observation, only one was finally found to be free from any other disease than the Red- leaf ; and the development and characteristics of the said disease in this vineyard were a great help in diagnosing the malady in other parts of the county, and under less favorable circumstances. The result of our investigations of the disease under consideration may be conveniently divided into two parts : (1) Description of the Red-leaf disease and its relationships ; and (2) Results of the winter and summer spraying experiments instituted to combat it. DESCRIPTION OF THE DISEASE AND ITS RELATIONSHIPS. The Red-leaf disease may affect the shoots, the leaves, the peduncles, the pedicel, and the fruit of the vine; it may affect the uppermost part of a cane, or several canes; one entire side of a vine, or, but more rarely, an entire vine. One vine may show all the characteristics of this disease, and another only a part, or perhaps,, only one of them- The disease may never proceed beyond the first stages, a not uncommon feature, or it may develop sloAvly until all its characters are patent to the most casual observer; more often, however, its development is rapid, and it would be somewhat difficult to distinguish the first stage, which is rather obscure, from those final stages which characterize it particularly. Allowing, then, for the irregularities in the development of the Red- leaf disease, and for the absence of anything like progression from one stage to another, the reader will find in the following description the means of identifying this disease, without much difficulty, whenever it occurs in his vineyard. Effect of the Disease on the Leaves. The leaves near the apex of the shoots, including those recently expanded, and perhaps for a foot or two down, become pale, especially in the interveinar spaces. If a leaf in this stage is picked and observed by transmitted light, and with the under- side facing the eye, all the fine network of veins will be found to be discolored. This discoloration of the small veins appears simultane- ously with the loss of color in the leaves; in the recently expanded OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. 7 leaves, which are naturally yellowish-green, this discoloration is more indicative of the disease than the change in color. Following the loss of color, the leaves become somewhat convex and the edges curl toward the lower surface; they lose their natural appearance; the tissue between the main veins sinks, and the veins themselves stand out like ribs. In mild cases the disease may develop no further than this. The affected leaves, however, fall off sooner or later, and generally with their stalks (petioles). In severe cases of the disease, the recently expanded leaves may dry up suddenly and totally without malformation of any kind; or, as occurs more frequently, the parenchyma becomes pale yellowish-green, and the inclosed network of small veins discolored; then, usually, the lobe, or at least the upper portion of it, or in entire leaves that portion of the parenchyma which occupies the equivalent position, including one wing of the petiolary sinus, becomes more or less convex and the tissue sunken between the veins, which stand out, often in bold relief. At this stage the tissues begin to dry rapidly from the periphery toward the petiole, at the same time retaining their peculiarity of form. When dry, the tissues are brittle and reddish brown. As soon as the discoloration has reached the petiole, the entire leaf and leaf-stalk may fall together. In older leaves, those not yet fully developed and still growing, one observes great variations variations which can not be accounted for by the position of the leaf in relation to other diseased leaves, or by its age. Some leaves show the characteristics just described as typical of recently expanded ones, except that they do not fall prior to the dying of the convex and furrowed area. The drying of that portion of the leaf proceeds as rapidly in one case as in the other. In the more fully developed leaves, however, the action is sufficiently striking. At the petiole, and in the region immediately adjoining it, the mid-rib serves as a line of demarkation between the living and the dead tissues. The dead tissue soon separates from the petiole, which, in turn, discolors. At this stage the leaf-blade separates from the petiole, which, though drying up and discoloring more or less from the apex down, remains a while longer attached to the shoot. In other cases, besides the dead and furrowed area, there may appear between the veins, on other parts of the leaf, spots which, at first yel- lowish, become, at the same time as the aforementioned area, dry and reddish-brown in color, except for a narrow margin next to the still green or greenish-yellow tissue. Or again, the leaves may present the following appearance: The leaf-tissue, while still green, becomes sunken between the veins; then, in one or sometimes both corners, the leaf becomes pale greenish-yellow and between the veins, in the remainder of the leaf, appear spots of various sizes of the same color. These spots enlarge and even run together to form stripes. At this stage the discolored areas begin to dry rapidly, assum- ing the familiar reddish-brown color. The tissues next the petiolary sinus rapidly dry up from the periphery inwards, but do not encroach upon the mid-rib, and one may sometimes find a leaf which still adheres to its stalk, after the parenchyma on each side has become detached. A slight margin of yellow T ish-green sometimes separates the dead furrowed area from the still living tissues; this margin of yellow is, however, generally more distinct around the spots and stripes of dead tissue in the other parts of the parenchyma. The leaves fall from the petioles, which soon follow r them. In fully-developed leaves and old leaves, the disease is not accom- panied by any distortion or furrowing of the leaf-blade. It affects only the tissues between the main veins, and first appears as suffused green- ish-yellow spots, which, at first indefinite, become gradually larger and more definite in outline, and often merge together, forming large macu- 8 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. lations and stripes, which are more or less yellow the intensity of the colorations depending, it would seem, on the rapidity with which the disease has progressed. The center of the spot now dies, becoming reddish-brown, sometimes almost with a brick tint and a sub-glossy appearance when death has been rapid. According to the rapidity of death these spots or stripes are surrounded, either (a) with a thin border of dull, deep red, which, in turn, is separated by a suffused yellow or greenish-yellow band from the green of the still healthy sur- rounding tissues; or (b) with a border of yellow, either suffused and broad, or thin and with a more definite margin; or (r) directly by the healthy green tissue itself. Sometimes the old leaves near the base of the shoots show a slight variation from the characteristics just described. These leaves, as soon as the disease begins to appear between the veins and the spots enlarge and merge to form stripes, become more or less greenish-yellow in the entire parenchyma. The dead areas, instead of being reddish-brown and in sharp contrast to the living tissues, are fawn-colored and soft, crumbly, tear easily, and fall away. The affected leaves thus become deeply incised, sometimes almost to the petiole, from which they hang in two, three or more pieces. In the case just described, as likewise in the preceding, the leaves may remain attached to the shoots for an indefinite time, and when they fall it may be either with the petioles, or before them. Effect of the Disease on the Fruit. The fruit of white varieties of grapes appears to be more sensitive to the Red-leaf disease than that of black varieties. It would seem that the latter show the character- istics of this disease more markedly on the foliage, except in severe cases, and toward autumn, whereas in the former the disease is more conspicuous on the berries. The Red-leaf disease may affect the fruit soon after setting. When this occurs, on passing the hand over a diseased bunch of grapes, the berries come off either with or without the pedicels. They even fall of themselves, and the stem (peduncle) dries up and falls also. This manifestation of the disease is more frequent among the red than the white grapes. The more noteworthy characters begin to show unmis- takably on the berries when the clusters of grapes are a month or a month and a half old, and only become general just prior to the begin- ning of maturation. The berries become suffused with livid discolora- tions, which are sub-cuticular, the cuticle itself not being affected until later. The tissue of the berries in the center of these spots generally falls away from the epidermis, which then collapses. The livid and sunken spots thus formed may be more or less numerous, and large or small; they are more frequent on the exposed berries than on those in constant shade; they are more frequent on the sides of the berries exposed to the light than on the shady sides. When they do not fall off at this stage, the berries shrivel and dry up. OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. When the berries become affected just previous to maturity, or after maturity has begun, they ripen imperfectly and, as a rule, are never worth picking. The clusters of diseased grapes are generally allowed to remain on the vine, and, after defoliation, they may be observed hanging from the canes. Effect of the Disease on the Shoots. The shoots are not affected directly by the Red-leaf disease. The symptoms they show are a consequence, so to speak, of the intensity of the malady on the leaves. When the shoots are partially defoliated (counting from the apex), their growth is only checked for a while. When the defoliation is more severe, the apex curls somewhat, discolors and dies. Death, however, is not con- fined to the apex, but proceeds for a greater or less distance down the shoots, the discoloration progressing, as it were, by stages. The shoots shrink and gradually turn brown. The shrinkage of the tissues is most noticeable near the nodes, and, except in more lignified parts of the shoots, always precedes the discoloration. The discoloration of the shoots is somewhat irregular, and more rapid in the parts exposed to the sun. When defoliation is complete, the shoots sometimes die from apex to base. When they are not defoliated, their lignification does not seem to be materially interfered with, though it is often irregular. One may even find, in rare cases, green immature spots or stripes in the midst of lignified tissue, but even such an irregularity as this does not persist. The immature spots mature in time. The Relationships of the Red-leaf Disease. The Red-leaf disease appears more or less closely related to the Folletage, the Rougeot, and the California Vine disease. It resembles the Folletage by the sporadic suddenness with which it sometimes appears; the Rougeot, in its not being immediately fatal, and possibly also in some of its foliar colora- tions; and the California (Anaheim) vine disease in the striping of the leaves. The cause of the Folletage and of the Rougeot has been thought to be due to the rupture of equilibrium between transpiration and absorption, but that of the California vine disease has not been determined. In the case of the Red-leaf disease, the evidence gathered in a single season seems to point to a physical rather than to a parasitic cause. Resemblance between the Red-leaf Disease and the Folletage. The Folletage affects the vines in midsummer. "One* sometimes observes, especially in July and August, vines in excellent health dying suddenly in a vineyard. The leaves wilt, fade, and dry; the shoots and even the arms succumb. The vines may die in a few minutes. * * * It is only isolated vines (they may sometimes be numerous) which are affected by this disease; * * * a whole vineyard is never affected. Entire shoots, or even whole arms, may be destroyed on a diseased vine *P. Viala: " Les Maladies de la Yigne," page 471. 10 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. without the other arms or shoots being affected." Vines planted in "deep, cool, damp soils" are subject to this trouble, especially when heat follows heavy rains. In dry soils the Folletage also occurs. In both cases it is due to a rupture of the equilibrium between the trans- piration of the leaves and the absorption of the roots. The resemblance between the effect of the Folletage and that of the Red-leaf disease is not a very close one. The Red-leaf disease is apparently not fatal in a single season, if ever. Like the Folletage, however, it affects the vines with greatest intensity and suddenness during July and August, and more frequently partially than wholly. The death, either total or partial, of the affected shoots does not follow the attack in the great majority of cases. In some cases of Folletage, the foliar characteristics are very similar to those of vines affected with the Red-leaf disease, if we may judge from plates 17, 18, and 19 given as illustrations of this disease in Bulletin No. 2 of the Division of Vegetable Pathology, U. S. Department of Agriculture. Resemblance between the Rougeot and the Red-leaf Disease. -The Rou- geot is considered by some authors as a mild form, so to speak, of the Folletage, and attributable to the same cause. The Rougeot affects vines as sporadically and irregularly as the Red-leaf disease. Its foliar characteristics remind one of those of the Anaheim, or the Red-leaf disease. Vines affected with Rougeot generally recover. Resemblance between the Red-leaf and the California (or Anaheim) Vine Disease. For a description of this disease the reader is referred to Pierce's memoir on the subject.* To describe the disease, even in the most summary manner, is not necessary in the present publication. The California vine disease and the Red-leaf disease are sufficiently different from each other, in their salient characteristics, to be easily distinguished without resorting to details. The reader will find, in the following comparison, a sufficient proof of the distinctiveness of these two diseases: Anaheim Disease.^ The disease is cumulative. The newly-formed leaf either remains green or is striped yellow or red, accord- ing as the grapes are white or red. (loc. cit., page 142.) As a rule the leaves fall from the base of the canes first, (loc. cit., page 45.) The roots are decayed, (loc. cit., page 57, et suiv.) Grapes dry and remain on the vine, or fall off, but not very frequently, (loc. cit., page 53.) A diseased vine shows the disease most generally on all its shoots, (loc. cit., page 79.) Red-leaf Disease. The disease is not cumulative. The newly-formed leaves either dry with deformation (leaves just expanded) or a re paler than normally and convex (leaves- two or more nodes from the apex). The leaves fall from the apex first. The roots are healthy. Grapes are mottled with livid, sunken spots. The number of shoots affected is variable, though rarely total. *Bull. No. 2, Div. Veg. Path., U. S. Dept. fN. B. Pierce: "California Vine Disease, Agr. " loc. cit. OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. 11 The above consideration of the relations of the Red-leaf disease leads one to conclude that the Red-leaf and the Rougeot are the more closely related. If this conclusion is proved to be correct, then the grower need not feel greatly alarmed even when a considerable percentage of his vines are affected with the Red-leaf disease. RESULTS OF WINTER AND SUMMER SPRAYING EXPERIMENTS. Toward the end of January, 1904, the active help of three growers, who were anxious to find a remedy for the Red-leaf disease, was obtained. The vineyards of these growers are situated respectively in the south, in the north, and in the east of Sonoma County. Those portions of their vineyards supposed to be most affected with this disease were selected for experimental purposes. It had been our intention to divide the plots off and to spray them after the manner shown in the following diagram, but owing to inclement weather the spraying with the iron sulfate was not completely carried out, except at the East Sonoma experiment plot. 1. Arrangement of Experiment Plots. 1 2 3 4 5 1 g s P C3 H M 5 ~a a ^ M K x 3 t ^ S BO 03 93 | o fl 1 O2 g s 5a S QJ 03 OJ 1 o fl | fl FH O 12 The TVor^/t Sonoma experiment plot was not sprayed with the iron sulfate at all, and the diagram of the plot as sprayed would be: Bordeaux mixture Witness Bordeaux mixture Witness Bordeaux mixture 12 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. The sprays used,* the dates of their application, the amount of each used per acre, and the length of the vine shoots when they were applied, are given in the following tables. From these tables the cost of the spraying, exclusive of the labor, may be approximately determined: Amount of spray used on fair vines of the Burger variety; 1210 vines per acre. Date. Acid Iron Sulfate. Bordeaux Mixture. Average Length of Canes. May 3 and 4 Was unable to 70 gallons 9 inches May 9 3 use this spray 85 gallons 30 inches June 7 - - - - - on account of 100 gallons 36 inches Julv 19 -. bad weather. 140 gallons ' 3.5-4 feet On the South Sonoma experiment plot half of the intended spraying with the iron sulfate was carried out. Amount of spray used on old, large vines of the Mission variety; 680 vines per acre. Date. Acid Iron Sulfate. Bordeaux Mixture. Average Length of Cane. . February 2 _ 400 gallons none April 28 none 80 gallons 9 inches May 13 none 105 gallons 20 inches June 14 and 15_ - _ _ _ none 270 gallons 3.5-5 feet July 18 none 530 gallons 4-6 feet The growth of the vines at the East Sonoma experiment plot was too uneven to be of value for tabulation. The three experiment plots very soon proved to be of very unequal value for the study of the Red-leaf disease. The vines in the East Sonoma plot were practically not affected by this disease, though seri- ously menaced by one which will be described below under the name of Grape-shrivel. The Red-leaf disease was prevalent in the North Sonoma plot, but so also was the Root-rot. At the South Sonoma plot, however, the vines were not affected with any other disease than the Red-leaf, and it is there that practically all the data on the development and progress of this malady were gathered. Notwithstanding the presence *The sprays used were: 1.25 per cent Bordeaux mixture, and acid iron sulfate. The acid iron sulfate is prepared as follows: Ten pounds of iron sulfate are placed in a half- barrel, one pound of commercial sulfuric acid is poured into the copperas (to prevent sputtering, which is objectionable, the acid should always be added before the water), then 12.5 gallons of water are added and the mass stirred until the sulfate has dissolved. In making large quantities of the acid iron sulfate spray it is more expeditious to use hot water. The iron sulfate is only a winter spray, and can not be used after the buds have swollen. OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. 13 of other diseases, the North Sonoma plot, and a few side excursions to other vineyards, were, however, of valuable assistance as soon as some knowledge of the characteristics of the Red-leaf disease had been obtained. By their aid the limits of variability of these characteristics were established with considerable accuracy. In the following discussion of the effect of our spraying experiments in controlling the Red-leaf disease, together with the observations on its progress and development in the vineyard, the data collected at the South Sonoma experiment plot form the basis of our discussion. Details of the Work at the South Sonoma, Experiment Plot. The plot was established among old Mission vines which had been more or less HflY TlEU) FIG. 1. Map of South Sonoma Experiment Plot. diseased in 1902 and 1903 and were beginning to cause some concern. By referring to the map (Fig. 1) the reader will at once see the manner in which the plot was laid off and sprayed. The times at which the sprayings were given have already been mentioned. The interval between the sprayings with the Bordeaux mixture was so timed as to always keep the leaves well covered with a film of the fungicide. The Bordeaux was observed to cause a certain amount of burning in the young leaves, especially in the earlier part of the season. This burning of the tissues, which occurs between the veins and in stripes, the leaves becoming, as a consequence, somewhat crinkled and distorted, should not be confused with the characteristics of the Red-leaf disease. The 14 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. vines sprayed with the acid iron sulfate were greener than the wit- nesses, at least during the first part of the growing season ; the vines sprayed with the Bordeaux mixture were much greener than the wit- nesses, even in the height of summer. This improvement in the color of the foliage, where and whenever the above fungicides are used, occurs regardless of the presence or absence of disease. The Red-leaf disease first appeared in the plot on the 10th of June, when a single vine was found somewhat affected. On the 10th of July there was hardly more than one per cent of the vines affected. From then to the end of the season, however, the disease rapidly increased. On the 25th of August about ten per cent of the vines were affected, which gives an increase of nine per cent in thirty-six days. From the 25th of August to the 13th of October-, the increase was only five per cent. If, instead of considering the plots as a whole, we compare the percentages of diseased vines among the sprayed and unsprayed rows, we will find that the Red-leaf disease develops almost as freely in the one case as in the other, with one exception. In the case of the witnesses (average of seven sections) the disease is more rapid from the 10th to the 28th of July than in the case of the sprayed vines ; but between July 28th and August 25th it is proportionately less rapid than among the vines sprayed with the acid iron sulfate and not much greater than among those sprayed with the Bordeaux mixture. The rapid rise in the percentage of diseased vines in the sprayed rows begins later than in the average of the witnesses, and on the 28th of July. On the 12th of August the vines sprayed with the iron sulfate show a greater percentage of diseased vines than the witnesses, and throughout the remainder of the season continue to do so. Among the vines sprayed with the Bordeaux mixture the percentage of disease remains below that of the witnesses, except on the 13th of October, when it is almost one percent higher. The vines sprayed with the iron sulfate and Bordeaux mixture (one section) showed 1.6 per cent diseased vines all through July; between July 28th and August 12th the percentage increased to 5.4 per cent, and from that date until October 13th the number of diseased vines gradually increased until it reached 9.3 per cent. (See Fig. 2.) The distribution of the diseased vines in the plot is quite sporadic. The disease does not progress from any one center, or many centers. In the map (Fig. 1) the position of the diseased vines on October 13th is marked by a circle; the crosses representing the vines. The reader will at once notice that the diseased vines are very scattered, their grouping very indefinite, and he would be unable to tell from the map where the disease first started. On the 10th of June there was one diseased vine in sections 6, 8, 12. On the map, which shows the posi- tion of the diseased vines on October 13th, there is not the remotest suggestion of four centers of infection. From this fact we may conclude that priority of infection has little to do with the spread of the Red-leaf disease. And this is the more especially worthy of note since priority of infection is generally a most decided factor in the spread of parasitic diseases. The reader has only to recall to mind the action of the Phylloxera, the Root-rot, the Mildew, etc. The parasite causing a given disease may spread from one plant to another in a more or less regular OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. 15 manner, which depends largely on the nature of the parasite and the surrounding conditions. If the parasite lives on the roots of the plant, it will spread, as it were, in a circle; but if it is a leaf parasite, the wind, all other things being equal, will cause the disease to spread with greater rapidity in the direction in which it blows. Furthermore, when a plant is preyed upon by some parasite, it shows all the symptoms character- istic of the specific disease, from the minor to the major in sequence. Now if we apply these principles to the study of the Red-leaf disease, Legend: Iron sulfate spray. Witnesses. Bordeaux mixture. Iron sulfate and Bordeaux mixture. 12 11 !. July. .August September. October, FIG. 2. Progress of the Red-leaf disease (in per cent) on the South Sonoma Experiment Plot. we find that it does not spread from a center of infection. A vine is often diseased on a single shoot; it may show the first symptoms of disease in the early summer, and never at any other time. Some healthy vines may in seven days be affected in the worst form, while others have only a cane or two, or even only the apical leaves of a few shoots, affected. These observations tend to show that the Red-leaf disease is not caused by a root parasite. It remains to be seen whether or not the Red-leaf disease can be caused by a leaf parasite. The disease progressed, the reader will remem- ber, from section 2 toward section 12 (Fig. 1). This progression was still 16 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. quite noticeable in July. The interesting feature of this progression is the fact that it was contrary to the direction of the wind, which blew daily across the plot in the direction shown by the arrow. The wind blew from right to left; the disease progressed from left to right; a leaf parasite would, other things being equal, follow the direction of the pre- vailing wind. Furthermore, the vines were, in at least seven tenths of the cases, more diseased to windward, notwithstanding the Red-leaf disease progressed against the wind. Again, the vines that were some- what weakened by their proximity to the eucalypti (see shaded part of map) and were shaded by them in the afternoon, were barely touched by the Red-leaf disease, and that only after the terrific hot weather in September.* The leaves of these vines were thinner and less consistent than those of the vines in constant sunlight. They were decidedly wanting in vigor, and yet remained practically untouched by the disease. It seems difficult to reconcile the above facts with the development of a leaf parasite. We are more inclined to believe that the Red-leaf disease is due to the same causes as the Folletage and the Rougeot, namely, a disturbance of the equilibrium between the absorption of water by the roots and its transpiration by the leaves. The soil in which the vineyard is planted is a clay loam underlaid, at a depth of from three to four feet, by an impermeable clay subsoil, at the left of the plot; in the middle, however, the soil is deeper and the subsoil more permeable; toward the right the soil becomes deeper still and more gravelly as one goes down. At the end of July there was from 2 to 3 per cent of free moisture in the soil, which is enough, as the vines showed, to support a good growth and crop of fruit, but which might easily become inadequate to supply the demands of the leaves in moments of great transpiration activity. Wind, as is well known, activates transpiration considerably and., under such conditions, might well become the inciting cause. If we take into consideration that the vines were more affected with the Red- leaf disease to windward, and that the disease progressed, in the early part of the season at least, from that part of the plot underlaid by the impermeable clay to that with the freer subsoil, we have two facts which bear out our hypothesis very well. This hypothesis, however, has against it the results shown by section 3, which was sprayed with the iron sulfate and the Bordeaux mixture. In this section, at the end of the season, there was not more than ten per cent of the vines diseased, whereas in the other sections the percentage of diseased vines was almost double. From the production of the vines in the different sections, we are unable to gather any evidence for or against our hypothesis. (See Fig. 3.) *This hot weather occurred on the 6th, 7th, and Sth of September, when the ther- mometer stood at 90 and 105 F. in the shade. OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. 17 In regard to the effect of soil fertility on the Red-leaf disease, some evidence well worthy of experimental control was obtained. In Sep- tember, 1903, in a cursory examination of the vineyard in which the experiment plot is situated, it was noted that the foliage in a " block " of old Mission vines which were much larger and at least ten years older than those in the experiment plot, showed very generally the discolora- tion of the Red-leaf disease. These old Missions were given a good dress- ing of stable manure during the winter of 1903. In 1904 they were kept more or less under constant observation. On September 16th of that year we noted that the old Missions, which the previous year showed the foliar characters of the Red-leaf disease so markedly, were still healthy. r TESOJ.VMD SPOT/HI rm rcon swjwre B -.vine arwwni \ira HORDE/NX mxruw vires unrrareo^rai UTT K> wrnuss. , W, TrSo W } B W, W t W 5 B W 6 B W, FIG. 3. Table showing the average production (in pounds) of the vines, both sprayed and unsprayed, at the South Sonoma Experiment Plot. From these observations one would surmise that fertilizing, with stable manure at least, would have a certain action in controlling the Red-leaf disease. If, moreover, coupled with these observations, it were found that the soil was at all deficient in one or all of the plant foods, then our surmise would become a plausibility, if not a certainty. We had, therefore, the soil (an average sample) of our experiment plot analyzed, and with the following result : The soil was found to contain less than 0.05 per cent of phosphoric acid, which is quite low for a productive soil. When we couple with this deficiency of phosphoric acid the fact that the grapevine consumes more of this nutrient than most fruit trees, it is not rash to assume that fertilization will greatly help the vines to at least withstand the Red-leaf disease. 18 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. THE GRAPE-SHRIVEL. The disease that we have denominated the Grape-shrivel is not as yet, at least so far as known, of any great economic importance; but, owing to the circumstances under which it occurs, it is highly probable that it exists elsewhere in the reconstructed vineyards of California and may, therefore, assume, at any moment, more than local interest. The fact that we observed the Grape-shrivel in the East Sonoma experiment plot, where it took the place of the Red-leaf disease, is sug- gestive enough, even though it was not observed at either of the other experiment plots, or in vineyards visited. Description of the Grape-Shrivel. The Grape-shrivel, as its name implies, is characterized by the shriveling of the berries. In fact, this shriveling is the only diagnostic character of this disease, the symptoms which appear in the leaves being easily referable to drought, or imper- fect nutrition. The Grape-shrivel develops quite rapidly, as shown by the fact that while no symptoms of the disease were observed on the 27th of June, yet on the 12th of July many vines were affected. By the end of July practically every vine in the experiment plot showed the characteristic shriveled grapes of this disease. The distribution of the Grape-shrivel is at first somewhat irregu- lar, then general. The grapes on weak vines (not necessarily dying vines) and strong vines are equally affected. The fruit on weak shoots and strong shoots is affected alike. The general health of the vine seems to bear no relation whatever to the distribution and intensity of the disease. Vigorous, weakly arid dying vines (all with affected grapes) commingle ; there are not the usual regular, or semi-regular, depressed areas of vegetation so characteristic of parasitic diseases. Effect of the Disease on the Grapes. The Grape-shrivel, as already mentioned, is characterized by its effect upon the fruit. The berries* lose their clear, turgid appearance and become dull and flabby (but never blotched, as in the Red-leaf disease), irregularly wrinkled and, as it were, thick-skinned; as the drying progresses the wrinkling becomes more pronounced and assumes a direction more nearly parallel to the axis of the berry (Fig. 4). When completely dry the berries are uniformly bluish, in some cases, where exposed to the sun, washed with red; they are tightly shrunken around the seeds, and coriaceous. At this stage the pedicels and the peduncle, to within a short distance of the cane, are dried and discolored; the green and dried portions of the peduncle become severed, and the completely desiccated bunch of *As we have only observed the Grape-shrivel on one variety of white grape (the Sernillon) the description of the effect of the disease on the berries can only apply integrally to varieties of the grapevine producing white fruit. OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. 19 grapes falls to the ground. Such is the progression of the disease in the grapes while they are still green, but, when they begin to mature the shrinkage becomes less total as the absolute percentage of sugar increases in the fruit. The fruit of diseased vines, when it does not shrivel, often ripens prematurely. This prematurely ripened fruit is frequently edible, though sometimes quite distasteful. The manner in which the malady works on the different bunches of the same cane is quite characteristic. The lower bunch of grapes is the FIG. 4. Bunches of grapes showing progress of Grape-shrivel. first to show signs of the disease; it is not rare for one to find the lowest bunch much diseased, and the upper just beginning to show the first nigns. We have even found, on canes bearing three bunches of grapes, the first bunch completely desiccated, the second shriveled, and the third absolutely sound. There are canes, however, in which the differ- ences are less marked, and some even in which the progression of the disease is reversed. Effect of the Disease on the Leaves. The disease does not show in the foliage at first. The leaves of strong, healthy vines and strong, healthy shoots remain turgid and green; the leaves of weaker vines and weaker 20 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. shoots may be somewhat faded and yellow. The yellow coloration may be total or partial, and the leaves irregularly dry in those parts of the parenchyma longest deprived of chlorophyll, that is from the edges inward. The lower leaves are more affected than the upper. Following the shriveling of the grapes, the foliage of the more vigor- ous vines, after a longer or shorter time, begins to show the same char- acters that the leaves of the weaker vines assume at an earlier period. These characteristics are illustrated in the accompanying colored figures on Plate I. The chlorophyll becomes resorbed at the edge of the leaf (Plate I, Fig. 7), which yellows; this resorption may continue until the whole of the leaf is bright yellow (Plate I, Fig. 1). Following this stage, which is not infrequent in the basal leaves, the leaf either dries up completely and at once (Plate I, Fig. 3), or, as occurs more often, from the periphery inward, with a slight rolling of the edges (Plate I, Fig. 2). In other cases, however, the entire blade of the leaf does not become so regularly yellow and then dry. Indeed, one fre- quently observes the yellowing at first confined to the apical lobe (Plate I, Fig. 4), and then gradually progressing toward the petiole (Plate I, Fig. 5), the wings of the leaf remaining the while of a sub-healthy green. The chlorotic tissue gradually dries, sometimes irregularly, but not infrequently in a very regular manner (Plate I, Fig. 6). As soon as the center portion of the leaf has dried, the wings of the leaf die. Fig. 6 represents a leaf, the center of which became chlorotic and then dried up; the death of the entire leaf then followed. A leaf presenting the characters of that illustrated in Fig. 8 is more exceptional. In this leaf the greater part of the leaf-blade was sud- denly killed without previous yellowing or chlorophyll resorption. The dead tissue, it will be observed, has a shade of green in it, whereas in all the other diseased leaves it is fawn-colored or brown. If the reader will imagine the dead tissue (Fig. 8) colored brown instead of greenish- fawn, he will have the representative of a leaf that was chlorotic around the edges and in the greater part of the blade. This chlorosis, however, did not spread, and the affected tissue rapidly died without impairing the functions of the remaining healthy portion of the leaf. Internal Appearance of the Shoots, Spurs, Arms, and Body of Vines. The spurs, the arms, and the body of the vine show no outward signs of disease at all. The shoots mature sometimes very unevenly, but this characteristic is unimportant. The shoots, spurs, and body of the vine show, however, certain internal symptoms which should be noted. Cross and longitudinal sections of the shoots, spurs, arms, and body of the vine show discolorations in the wood and pith. In the shoots a slight discoloration of the woody tissue next the pith can be traced with comparative ease at least as far as the last bunch of grapes showing shriveling; but the brown discolorations in the pith are not so constant: OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. 21 now and then they may occur just above and below the diaphragms, and without regularity; at other times a slight discoloration of the pith may be traced from the base of the shoot up several nodps. In the spurs the woody tissue of the previous year is brown and often, more especially near the edge, zoned with darker lines. In the arms we have the same general appearance as in the spurs, with this difference that, in cross-section, the darker areas may be more suffused. In the trunk the discolorations of the wood are less pronounced and, in longitudinal section, appear as striations which become less numerous as one nears the stock (the diseased vines are grafted on Lenoir), which they rarely penetrate to any extent; or, if no decay or dead tissue is present, the live wood may be suffused with a faint brown tinge, from which the striations stand out less boldly. The bodies of the vines have, however, in most cases suffered more extended disorganization than just described. One finds, whenever large limbs have been at one time removed, decay and dead tissues occupying a large part of the body of the vine and eating gradually down toward the stock, which is rarely affected, how- ever, to any serious extent. The roots are always healthy, even in sickly vines. Generalities regarding the Work at the East Sonoma Experiment Plot. This plot was established in a vineyard reconstituted some twenty years ago. Lenoir was the grafting stock originally used; but from time to time, as vacancies occurred, other stocks mostly Rupestris of the Fort Worth type were used to fill in the missing places. In that part of the vineyard selected for the experiment plot (the only really diseased portion) the Lenoirs are carrying Semillon grafts. The plot, however, is not free from admixture. A few Zinfandels are scattered here and there and were evidently accidentally introduced when refilling the vacancies. When the vineyard was reconstituted the grafting was well done and the grafts were not allowed to strike root. Furthermore, there was never any great disparity of growth between the stock and graft, and consequently the unions are smooth. The vines were pruned short prior to 1902, and, in consequence, had never produced much of a crop,, the Semillon being one of the grapes that demands long pruning to produce fully. The vines, however, under, this regime, were moderately healthy and sufficiently vigorous. In 1902 the system of pruning was changed from short to long. Following the adop- tion of the long pruning the vines began to show disease. In 1903 they were already much affected. This new disease was then supposed to be the Red-leaf disease. We now know that it was the Grape-shrivel. Acting on the assumption that the disease in this vineyard was the Red-leaf, arrangements were made in February, 1904, to carry out there the same spraying experiments as at the other two plots. The East Sonoma plot was divided into twelve sections, containing four rows of vines each. Sections 1 and 7 were sprayed with acid iron sulfate, * sections 3 and 9 with acid iron sulfate and Bordeaux mixture; sections 2, 4, 6, and 12 were left as witnesses. Sections 1, 3, 7, and 9 were *For the method of preparing this fungicide, see page 12. 22 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. sprayed with the acid iron sulfate on the 28th of March, just as the buds were beginning to swell. Sections 3, 5, 9, and 11 were sprayed with Bordeaux mixture (4 pounds of copper sulfate, 4 pounds of lime, 40 gallons of water) 011 the 6th and 26th of May, and the 16th of June. The growth of the vines on the sprayed and unsprayed rows was sporadic and uneven. After the second spraying with Bordeaux mixture the foliage of the sprayed vines was somewhat greener than that of the witnesses. By the 16th of June, the date of the third spraying with the Bordeaux mixture, no specific signs of disease had shown in either the witnesses or the treated vines, other than such as might be referred to known causes. The appearance of the plot was in no way such as to create a fear that the vines would collapse and fail to ripen their fruit. On the 27th of June the general appearance of the vines was somewhat wan, and the line of demarkation between the sprayed and unsprayed vines had well-nigh ceased to exist. On the 12th of July, however, almost every vine in the plot showed unmistakable signs of suffering; the foliage was pale, and many clusters of grapes had already shriveled, or were just beginning to collapse; there was no longer any difference between the witnesses and the sprayed vines. In fact, so general were the symptoms of disease in both the treated and untreated vines that any further attempt to check it with Bordeaux mixture was given up as useless. By the end of July practically every vine in the experiment plot was affected with the Grape-shrivel, with the exception of the Zin- fandels and the non-grafted Lenoirs. On the 21st of July, when well-nigh every vine in the plot was affected with the Grape-shrivel, the free moisture in the soil, a loam underlaid at the depth of two feet with a gravelly clay-subsoil, varied between nine and ten per cent. The roots of the stock in different parts of the plot were examined from time to time for the purpose of determining their resistance to the Phylloxera. Nodosities were always found to be present in plenty, both on the grafted and on the non-grafted Lenoirs. At the end of July one per cent of the vines in the experiment plot were dug up, split open and examined. The result of this examination is given on page 20, where the internal appearance of the shoots, spurs, and body of vines affected with the Grape-shrivel is described. In the beginning of August a critical examination was made of the vines in the plot, for the purpose of determining if there was any rela- tion between the vigor of the vine or of any of its individual shoots, and the Grape-shrivel. The only fact this examination clearly revealed was that the vines had been given too liberal a pruning. In general, no more than half the eyes left at pruning time had sprouted, and sometimes less. The yield of the experiment plot (one acre) was about 700 pounds of OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. 23 grapes. The Grape-shrivel had destroyed the four or five tons of fruit that the showing of the vines in June would have led one to expect. Cause of the Grape-shrivel. From the description of the Grape-shrivel, and the manner and circumstances under which it develops, it is evident that the disease is a peculiar manifestation of imperfect nutrition. The yellowing and dying of the leaves, beginning at the base of the shoots, is characteristic of vines suffering from want of water. Premature ripening is also a consequence of lack of water. The fact that the grapes shrivel, often previously to the discoloration and wilting of the foliage, does not invalidate this contention; for, it may be shown that under the influence of drought, or a paucity of free water in the soil, the fruit of the French prune will shrivel even when the foliage is healthy and luxuriant. It is, therefore, no stretch of the imagination to suppose that the same phenomenon happens in the case of the vine. In fact, in several cases we have obtained experimentally the characteristics of the Grape-shrivel as shown in the grapes. Our experiments, though crude enough, were quite instructive. We severed, in healthy vines, several long canes bearing vigorous shoots carrying well-developed bunches of grapes. Almost immediately after the canes were severed the shoots began to wilt, as one would expect. The bunches of grapes, however, generally wilted as they do in the case of the Grape-shrivel: the lower bunches on a shoot would frequently dry out faster than the others. We also observed that the pith discolored in the neighborhood of the diaphragms first, and that the wood tissue became discolored. The discoloration of the pith in the shoots, and the discolorations in the spurs, arms, and trunk, may be shown to occur in vines under very varied and divers circumstances, and are, therefore, at most of but secondary importance. The symptoms of the Grape-shrivel, then, are those of a vine suffering from drought. This is further emphasized by the following facts: The Lenoir, the stock upon which the Semillons are grafted, is not very resistant to the Phylloxera. Its rootlets (which, the reader will bear in mind, are the active agents in the absorption of water) were much distorted by the Phylloxera, and their functions, therefore, inter- fered with. This fact explains how it is that a vine grafted on Lenoir (or any other stock sensitive to the Phylloxera) could suffer from want of water, even when the soil contained nine or ten per cent of free moisture. But it may be asked, why does the non-grafted Lenoir not suffer ? This question is easily answered. The Lenoir is not as vigor- ous a grower nor as heavy a bearer as the Semillon. When it bears the Semillon, then, or any other vinifera more vigorous than itself, its rootlets, even when not preyed upon by the Phylloxera, are unable to take up and transfer to the graft its optimum of food; and the bigger 24 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. and finer the graft the greater the difficulty the Lenoir has in supply- ing it with its full quota of nutriment. But if the rootlets of the Lenoir are much damaged by the Phylloxera, the equilibrium can not be maintained and the graft will show signs of distress. Why, then, have the vines at the East Sonoma experiment plot lived so long ? The answer to this question is, that the vines were formerly short-pruned and were unproductive, but that since 1902 they have been long-pruned and made to produce largely. In the first case the equilibrium between the stock and the graft was practically maintained; in the latter, it was destroyed. It must not be forgotten, however, that the Phylloxera is in a measure an active agent in causing the Grape-shrivel, and that the severity of the disease during 1903 and 1904 may be due to circumstances favoring the development of this pest. In combatting the Grape-shrivel on grafted vines, two things must be taken into account: First, the affinity between the stock and the graft; second, the resistance of the stock to the Phylloxera. The affinity (and by affinity we mean all the necessaries to a con- joint life) between stock and scion is to be maintained in equilibrium by judicious pruning, supplemented by thorough fertilization. The resistance of the stock to the Phylloxera will be indirectly heightened by fertilization; but if then found to be insufficient, it should be changed for a more resistant one. The use of bisulfid of carbon, in protecting stocks of low resistance from the attacks of Phylloxera, is not at present an economic possibility. ROOT-ROT.* The action of this disease in its main characteristics is very similar to the malady known among the French as the Pourridie, or Blanc des racines, and in Germany, according to Mr. P. Viala,f by the name of Weinstock-faule. The areas of depressed vegetation that one associates familiarly with the action of the Phylloxera, are characteristic also of the Root-rot. In each case there is a center of infection, though, when compared with the Phylloxera, the Root-rot spreads more slowly and appears circumscribed or local in its action. In the case of the Root- rot there may occur many small centers of infection in close proximity to one another which may take several years to merge into one; whereas, in the case of the Phylloxera, when infection is so general that several centers start very near one another, they rapidly become one. * These remarks of Mr. Butler on the Root-rot are of very great importance at the present time, as this disease is doing a great deal of damage in certain parts of Santa Clara, Sacramento, and San Joaquin valleys. In some districts the Root-rot is far more destructive than the Phylloxera. <(E. H. T.) t P. Viala: "Les Maladies de la Vigne," 3d ed., page 248. OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. 25 The Root-rot is caused by a fungus, possibly several, fungi, and in its usual form is very easily recognized upon digging up any vine within an infected area. The roots are soft, watery, yellowish-brown in the entire woody cylinder, and more or less permeated with whitish threads the mycelium of the parasite and give off a strong nauseous fungous odor. As the lower roots are destroyed, and the mortification enters the body of the vine and slowly eats its way in the trunk to the surface of the soil, and even above, new roots are sent out from the still healthy encompassing tissue; these roots, in turn, become riddled with, and succumb to the attacks of the fungus. In the last stages of the disease (that is, when the vine has sent out a few feeble canes about a foot long) one invariably finds near or at the surface of the soil, a very free growth of young tender roots. Though the Root-rot is generally of the form just described, and takes from two to five years to kill the vine, it may, in some rare cases and in young vineyards, spread with such rapidity that it kills the vines in eighteen months, and even in a single season. Mr. P. Viala observes: "The vines may succumb in from fifteen to eighteen months," and that he "has even caused their death in six months by placing them under the most favorable conditions for the development of the Pourridie." * The author observed, during the summer of 1904, in a young vine- yard, a remarkably intense and destructive attack of Root-rot, which, in many instances, had gained an entrance into the vines during the late spring or early summer, and had practically ruined the greater part of them by October. Many there were that would not "come out" in the spring, or, if they did, would die during the summer. The growth of vines affected with the usual form of Root-rot resembles that of vines affected with the Phylloxera. Their growth gradually becomes weaker and weaker, and the vines finally die. But in the rapid form of this disease there is no such gradual wasting away. The foliage of the vines becomes chlorotic, and, if the weather is at all unfavorable, rapidly sears and falls off. The blade of the leaf not infrequently sep- arates from the petiole, which remains a while longer attached to the shoots. The maturity of the shoots is impeded; their lignification is imperfect, irregular, and at times resembles that which has come to be considered typical of the Anaheim disease; in other words, strips on elongate spots of immature tissue may be found in the midst of mature wood. The fruit matures imperfectly. The photograph of the vine shown in Fig. 5 was taken early in October, and shows the general appear- ance of a young vine affected with the rapid form of the Root-rot. The vine was evidently not affected with this disease, if we may judge from its growth, until late in spring. The appearance of the diseased vines below ground is necessarily different from that of those affected with the milder form of the Root- *P. Viala: "Monographic du Pourridie," Introduction. 26 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. rot. Instead of the entire underground portions being soft, watery, and decayed, the woody cylinder suffers no outward disorganization, but is more or less discolored according as it is examined nearer to or farther from the original center of infection. In fact, so slight is the FIG. 5. Young vine killed by Root-rot. decay of the tissues that a vine, when cursorily examined after it has been dug out, shows no signs of a specific disease. The bark on the stem is tight and dry, and is not suggestive ; on the roots it is often streaked with filmy white, but even this is not characteristic enough to hold OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. 27 one's attention. But when one examines a diseased vine a little more closely he discovers that it gives off the nauseous fungous odor so characteristic of the Root-rot, and that a cross-section through the stem or roots shows, between the wood and the bark, a dirty white sub- continuous line, which is not very distinct and is easily overlooked. If, however, a piece of the bark is cut off, there will appear between it and the woody cylinder a white, or grayish felt-like, mass of interwoven threads the mycelium of the Root-rot fungus. The vine shown in Fig. 5 was one mass of this fungous growth to within an inch or so of the surface of the soil. The vineyard in which the exceptionally severe form of Root-rot just described was observed had been established in 1902, on land that had been cleared during the year 1900. The piece of land on which the vineyard is planted lies on the sunny slope of a fairly steep range of hills. This slope in profile might be likened to an S reversed and con- siderably drawn out lengthwise, and lying at an angle of about thirty degrees with the horizontal. The soils in this piece of land are both poor and good. Beginning at the bottom, and extending up the slope some one hundred feet, we find a very shallow sandy soil, inclined to be compact and hard, and underlaid, at a depth of a foot or more, with a clayey subsoil. This soil becomes very wet in winter. On the remain- der of the slope the soil is friable, inclined to red, fertile, and with the subsoil considerably below the surface. In this soil the vines may be completely dug out with a spade, whereas a mattock, and a good one, is needed to remove the vines from the soil at the bottom of the hill. The growth of oaks, before the land was cleared, was meager at the bottom of the slope, on the refractory soil, but quite dense everywhere else. A year after the land was cleared the vines were planted. They were Carignanes grafted on resistant stocks. On the light, friable soil the Rupestris St. George was the stock employed; whereas on the refractory soil at the bottom of the hill, Rupestris of the Fort Worth type appears to have been exclusively used. The former were more vigorous than the latter. These being the facts one would naturally expect the Root-rot to develop first among the Fort Worth Rupestris, and spread from these to the Rupestris St. George. This would certainly have been more in accord with the general behavior of Root-rot fungi. The reverse was true, however; the Rupestris St. George and not the Fort Worth Rupestris were the vines affected. But with the Root-rots, like with many other parasites of both the vegetable and animal kingdoms, the usual areas of adaptability, when one or more conditions are particularly favorable, may be passed over. In fact, it is well known that in the case of the Root-rot, though usually serious only in wet soils, it may spread in comparatively dry 28 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. soils if the plants growing in said soils happen to be sensitive to the disease, and climatic conditions a wet Avinter, for instance -are favorable. In the case of the rapid form of the Root-rot affecting the young vineyard above mentioned, we know that the land was full of decaying roots and other debris from the oaks that had been grubbed out; we also know that Rupestris St. George is very sensitive to this disease, and, furthermore, that the latter part of last winter was wetter than usual. The intensive and rapid growth of the Root-rot in a three-year-old vineyard grafted on Rupestris St. George, and established in a soil which, from its situation and friability, would be considered unfavor- able to the development of the parasite, is beyond a doubt exceptional. However, this particular case has been dwelt upon, less on account of its economic importance than for the fact that it demonstrates very conclusively the sensitiveness of the Rupestris St. George to Root-rot, a point which we shall have occasion to dwell upon again. Vines affected with the rapid form of the Root-rot can not, of course, be saved. Vines affected with the usual form are, when treate'd before the disease has made much progress, amenable to treatment. The pre- ventive treatment here recommended applies equally well to both forms of Root-rot. The remedial or preventive measures used in combatting the Root-rot, or indeed any other disease attacking the subterranean organs of plants, are, at best, but palliatives. As the disease is more general in soils with an impermeable substratum that are quite retentive and miry after heavy rains, adequate drainage is and will always remain the only valuable preventive and curative measure. For excessive humidity is the exciting cause of the disease; it favors fungous development, and the tissues of the roots are soft, gorged with water, and in no condition to resist the attacks of parasites. An author (Mr. P. Viala*) who has studied the Pourridie of the vine and fruit trees with particular care, says: "One must, to prevent the disease from spreading, and to protect one's self against it in new plantations, thoroughly drain the soils in which it exists, and also those that are, through their retentiveness, favorable to its development." "Drainage is an excellent preventive measure," he continues, "and what is more, the only efficacious one." But as drainage is not always economically possible, a few half measures that are at least useful may be mentioned, even if they have not the virtue of an elixir. As soon as the disease shows in the vineyard, all badly diseased vines (that is, those vines whose scant growth shows that their main root- system is seriously attacked) should be removed and the vines surround- *Loc. cit., page 248. OBSERVATIONS ON SOME VINE . DISEASES IN SONOMA COUNTY. 29 ing them treated with a three per cent solution of blue vitriol* or a seven per cent solution of green vitriol. f This is done by digging with a hoe a small basin around the trunk of the vines and pouring into it a gallon or so of either solution, the quantity being determined by the nature of the soil and the supposed extent of the root-system. If for any reason it is inconvenient to treat the vines with either of the vitriol solutions, a pound of either the bluestone or the copperas may be placed around the trunks and allowed to dissolve in the winter rains; but this method will not be as effective. Before replanting the areas destroyed by the rot, the holes destined to receive the young vines should be partly filled with either blue or green vitriol solution, and then, when the fungicide has soaked away, planted. In soils that are subject to the Root-rot, rooted vines should always be planted, and as shallowly as cultivation will permit. Cuttings should never be used, for they have to be planted deeper than rooted vines, the chances of infection, especially on the cut surface, being thereby increased. Vineyards that have once been infected with the Root-rot are, unless drained, always subject to it; therefore, it is essential that those parts that have been destroyed by this disease should, when replanted, be treated every two or three years by one of the methods above outlined. The Root-rot attacks not only the common grapevine ( Vitis vinifera), but probably also more or less severely the different resistant stocks. The Rupestris St. "George is very sensitive to it; but according to Mr. Jallabert,J whose demonstration is quite convincing, the Riparia X Rupestris 3306 is almost immune. He planted the latter in a soil infected with the Pourridie and which, even in the dog days, could only be worked to a depth of six inches. "Somewhat below this the clay was saturated, and, lower down, mud." In such a soil as this, and despite the Pourridie, the 3306 flourished. We may feel confident, then, that wherever the Root-rot is bad in California, the Riparia X Rupes- tris 3306 will more than hold its own. *J. Dufour in "Chronique Agricole du Canton de Vaud," quoted by G. Foex, " Cours Complet de Viticulture," 4th ed., page 603. t J. Bonjour: " Manuel Pratique du Vigneron," page 71. \ J. Jallabert: " Resistance du Rupestris du Lotet du Riparia X Rupestris 3306 au Pourridie," Revue de Viticulture, tome XI, page 92. Loc. cit., page 5)4 et suiv. CALIFORNIA PUBLICATIONS AVAILABLE FOR DISTRIBUTION. REPORTS. 1896. Report of the Viticultural Work during the seasons 1887-93, with data regarding the Vintages of 1894-95. 1897. Resistant Vines, their Selection, Adaptation, and Grafting. Appendix to Viticultural Report for 1896. 1898. Partial Report of Work of Agricultural Experiment Station for the years 1895-96 and 1896-97. 1900. Report of the Agricultural Experiment Station for the year 1897-98. 1902. Report of the Agricultural Experiment Station for 1898-1901. 1903. Report of the Agricultural Experiment Station for 1901-1903. 1904. Twenty-second Report of the Agricultural Experiment Station for 1903-1904. BULLETINS. Reprint. Endurance of Drought in Soils of the Arid Region. No. 129. Report of the Condition of Olive Culture in California. 131. The Phylloxera of the Vine. 132. Feeding of Farm Animals. 133. Tolerance of Alkali by Various Cultures. 135. The Potato- Worm in California. 137. Pickling Ripe and Green Olives. 138. Citrus Fruit Culture. 139. Orange and Lemon Rot. 140. Lands of the Colorado Delta in Salton Basin, and Supplement. 141. Deciduous Fruits at Paso Robles. 142. Grasshoppers in California. 143. California Peach-Tree Borer. 144. The Peach-Worm. 145. The Red Spider of Citrus Trees. 146. New Methods of Grafting and Budding Vines. 147. Culture Work of the Substations. 148. Resistant Vines and their Hybrids. 149. California Sugar Industry. 150. The Value of Oak Leaves for Forage. 151. Arsenical Insecticides. 152. Fumigation Dosage. 153. Spraying with Distillates. 154. Sulfur Sprays for Red Spider. 155. Directions for Spraying for the Codling-Moth. 156. Fowl Cholera. 157. Commercial Fertilizers. 158. California Olive Oil; its Manufacture. 159. Contribution to the Study of Fermentation. 160. The Hop Aphis. 161. Tuberculosis in Fowls. 162. Commercial Fertilizers. 163. Pear Scab. 164. Poultry Feeding and Proprietary Foods. 165. Asparagus and Asparagus Rust in California. 166. Spraying for Scale Insects. 167. Manufacture of Dry Wines in Hot Countries. CIRCULARS. No. 1. Texas Fever. No. 10. Reading Course in Economic 2. Blackleg. Entomology. 3. Hog Cholera. 11. Fumigation Practice. 4. Anthrax. 12. Silk Culture. 5. Contagious Abortion in Cows. 13. The Culture of the Sugar Beet. 6. Methods of Physical and Chem- 14. Practical Suggestions for Cod- ical Soil Analysis. ling-Moth Control in the 7. Remedies for Insects. Pajaro Valley. 9. Asparagus Rust. Copies may be had by application to the Director of the Experiment Station, Berkeley, California. UNIVERSITY OF CALIFORNIA AGRICULTURAL EXPERIMENT STATION COLLEGE OF AGRICULTURE E. j. WICKSON, ACTING DIRECTOR BERKELEY, CALIFORNIA CIRCULAR No. 26 (SEPTEMBER, 1906.) SELECTION AND PREPARATION OF VINE-CUTTINGS, BY FEEDEEIC T. BIOLETTI. One of the most important factors in determining the profitableness of a vineyard is the choice of the cuttings which are used to start the vineyard. This factor is very generally neglected, or when a choice is made it is often not the best. Any one who will carefully examine the vines in a vineyard cannot help being struck with the great variation in the amount of crop on different individual vines. Sometimes this variation can be traced to differences in pruning, to accidental injuries, to more or less irrigation, or to variations in soil and position. There is, however, a good deal of variation which cannot be ascribed to any of these causes and which exists in every vineyard, no matter how uniform the conditions or how careful the cultivation. This variation is something which is inherent in the vine and can- not be overcome by any cultural method. It is much greater in some varieties than in others. With some varieties it is so great that certain vines are recognized as almost sterile and are commonly called "mule" vines in California. With other varieties the variation is much less noticeable, but is none the less real, and by weighing the crop of each vine in a row it will be found, even with the most uniform producers, to exceed 50 per cent. If every vine in the vineyard bore as much as the vine with the heaviest crop the total production of the vineyard would be much increased. By grafting the poor bearers with cuttings from the best bearers the crop in a vineyard' has been more than dou- bled. Vineyards of unselected Cabernet produce on the average about two tons to the acre. Cabernet vineyards from carefully selected cut- tings have produced nine tons. Owing to the great natural fertility of most of our Calif ornian vineyards, due to favorable soil and climate, these facts have not re- ceived the attention they deserve. In most parts of Europe, and even in South Africa, more care is taken in the selection of cuttings than here. In many vineyards the vines bearing the best crops are marked and cuttings taken only from these. In others only those cuttings are used which are made from bearing wood ; that is, from canes which have borne grapes, as shown by the remains of the bunch stalks, or by the position of the cane on the vine. UNIVERSITY OF CALIFORNIA AGRICULTURAL EXPERIMENT STATION -COLLEGE OF AGRICULTURE E. j. WICKSON, ACTING DIRECTOR BERKELEY, CALIFORNIA CIRCULAR No. 26 (SEPTEMBER, 1906.) SELECTION AND PREPARATION OF VINE-CUTTINGS. BY FEEDEEIC T. BIOLETTI. One of the most important factors in determining the profitableness of a vineyard is the choice of the cuttings which are used to start the vineyard. This factor is very generally neglected, or when a choice is made it is often not the best. Any one who will carefully examine the vines in a vineyard cannot help being struck with the great variation in the amount of crop on different individual vines. Sometimes this variation can be traced to differences in pruning, to accidental injuries, to more or less irrigation, or to variations in soil and position. There is, however, a good deal of variation which cannot be ascribed to any of these causes and which exists in every vineyard, no matter how uniform the conditions or how careful the cultivation. This variation is something which is inherent in the vine and can- not be overcome by any cultural method. It is much greater in some varieties than in others. With some varieties it is so great that certain vines are recognized as almost sterile and are commonly called ' ' mule ' ' vines in California. With other varieties the variation is much less noticeable, but is none the less real, and by weighing the crop of each vine in a row it will be found, even with the most uniform producers, to exceed 50 per cent. If every vine in the vineyard bore as much as the vine with the heaviest crop the total production of the vineyard would be much increased. By grafting the poor bearers with cuttings from the best bearers the crop in a vineyard' has been more than dou- bled. Vineyards of unselected Cabernet produce on the average about two tons to the acre. Cabernet vineyards from carefully selected cut- tings have produced nine tons. Owing to the great natural fertility of most of our Californian vineyards, due to favorable soil and climate, these facts have not re- ceived the attention they deserve. In most parts of Europe, and even in South Africa, more care is taken in the selection of cuttings than here. lii many vineyards the vines bearing the best crops are marked and cuttings taken only from these. In others only those cuttings are used which are made from bearing wood; that is, from canes which have borne grapes, as shown by the remains of the bunch stalks, or by the position of the cane on the vine. It is perhaps not right to say that no choice is exercised in the selec- tion of cuttings in California. There is inevitably some choice, though principally unconscious and generally harmful. The man who is mak- ing cuttings will, if he has no other standard, choose those canes which he can work up with the greatest ease. These are the long, unbranched canes from the most vigorous vines. Such canes are usually suckers or water-sprouts, the least fruitful on the vine, and the most vigorous vines are generally those which have produced the fewest grapes. Such selection as. this cannot fail to be harmful, especially with the finer va- rieties, which vary more than the common, and must finally result in the deterioration of all varieties. The ordinary European method of simply marking the vines which bear good crops the year the cuttings are taken is imperfect and can do no more than keep the varieties from deteriorating. By more care- ful selection, continued systematically for a series of years, it has been proved possible to greatly increase the bearing qualities of certain va- rieties. Other qualities besides that of more or less productiveness could undoubtedly be influenced by the same means. In this way nu- merous variations of the Pinot or Burgundy have arisen. These varia- tions differ from the type in color, acidity, time of ripening, and even in flavor. It would probably be possible to produce a loose bunched Tokay, a close bunched Zabalkanski, or a large fruited Sultanina in the same way. There is no quality, however, which varies so much with individual vines as that of bearing, and there is no quality that is so quickly and easily influenced by cutting selection. It is this quality, therefore, which should receive most attention in choosing our cuttings. The modification of other characteristics is the work of the plant breeder and is too slow, difficult and uncertain for the practical grape grower. It is, moreover, at least in the case of wine grapes, unnecessary, for we can find almost any quality we want among the two or three thousand known varieties of wine grapes, but unfortunately not always com- bined with high productiveness. The most promising means of obtain- ing the rara avis we desire is to commence with a variety possessing the necessary flavor, color and chemical composition and by proper cut- ting selection to bring up its productiveness to the desired degree. It would be much easier to "grade up" the Cabernet until it bore crops equal to those of the Carignane than to attempt to improve greatly the flavor and color of Carignane by selection. Method of Selection, The first question to be settled is, of course, what variety should be chosen. This will depend on whether it is in- tended to raise table, raisin, or wine grapes, and if wine grapes, on the kind of wine desired, sweet or dry, red or white, and also on a multi- plicity of local and market conditions. The question of variety is too lar^e and complicated for treatment here and has already been given much attention in various publications of the Station. Only the ques- tions regarding the means of obtaining cuttings capable of growing into strong,' heavy bearing vines will be considered here. The Locality. Any locality where the vine grows vigorously and ripens its wood regularly will produce good cuttings. As a rule the warmer localities produce the best wood, heavy, firm and well nour- ished. The canes on vines grown very near the coast, as at Berkeley, are often soft and pithy. Certain varieties such as Refosco and Almeria do not ripen their wood well in the cooler parts even of Sonoma and Santa Cruz counties where they are exposed to frequent sea fogs during the summer. Being immature when the frosts cause the leaves to fall, the canes are easily attacked by saprophytic fungi. The work of these fungi is often seen in the blackened or mottled ap- pearance of the canes. Any discoloration of the canes is a bad sign, whether it is caused by fungi wl^ich only attack imperfectly matured wood, or by parasitic fungi, such as oidium, which may occur any- where. With the exception of a few isolated localities quite near the coast, it may be said that good, well ripened cuttings may be obtained from any of the vine-growing regions of California. Vine Diseases. An exception should perhaps be made to this state- ment as regards localities where the so-called Anaheim disease is prev- alent. Until we know more about that disease it is wiser to avoid obtaining our cuttings from such regions. That this disease can be transported and communicated by cuttings is perhaps not thoroughly demonstrated, but at all events the disease results in poor growth and poor wood, and cuttings from diseased vines cannot be expected to give the best results. With regard to other diseases there need be no fear of their intro- duction into the vineyard by means of cuttings. Phylloxera can be guarded against by proper disinfection of the cuttings and all other vine diseases, which exist in California, are found in every district. This is not true as regards rooted cuttings. There is no sure and prac- ticable method of destroying Phylloxera on the roots, and rooted vines should be introduced into a new district only with extreme caution. While there need be no fear of introducing Oidium, vine-hoppers, etc., for they exist in every vine-growing region of California, no cut- tings should be used which show distinct signs of their attacks, as such signs are proof that the vines from which the cuttings came were not perfectly healthy, and unhealthy vines do not produce the best cut- tings. The Vineyard. As a rule it is best to obtain the cuttings in the district where they are to be planted, if the desired variety is grown there. The only exceptions to this rule are for districts where Ana- heim, Oidium, or some other disease is so prevalent that it is difficult to find perfectly healthy vines. The locality being decided on, it is not a matter of indifference what vineyard is chosen. Only a well kept, vigorous vineyard can pro- duce the best cuttings. If the vineyard is badly cultivated, the vines mildewed, or the grapes of poor quality, it is a bad source for our cut- tings. A vineyard which has healthy vines producing paying crops of good grapes is the best place to get them. The Vines. Given the locality and the vineyard : from which vines in this vineyard shall we take our cuttings ? This is the most impor- tant question of all and that which is most generally neglected. It is hardly necessary to say that no cuttings should be taken from vines which have never produced a good crop. Some such vines exist in nearly every vineyard. A few growers mark such vines and avoid them when making cuttings. It would be better to graft them over or dig them out. Instead of marking the poorest vines in order to avoid them, it is better to mark the best vines in order to choose them when making cut- tings. When the crop is ripe and still on the vines the vineyard should be gone over carefully and a sufficient number of the best vines marked to supply the amount of cuttings needed. Only vines showing health, vigor and heavy crop of well-ripened grapes should be marked. A dab of paint on the stake or the stem of the vine is perhaps the most con- venient way of marking. While this will insure our cuttings coming only from vines which are capable of producing a satisfactory crop, it omits one very impor- tant factor the regularity of bearing. Some vines bear good crop occasionally, or on alternate years. The ideal vine is one which bears a good crop every year. This vine we can find only by keeping a con- tinuous record of its performance. This can be done to some extent by going over the vineyard every year just before the vintage and marking every vine which has a good crop. At the end of four or five years the vines which have borne a good crop every year will show four or five marks, and these are the vines most likely to yield cuttings ca- pable of producing a vineyard of ideal vines. To make this selection most effectively and quickly would require a special vineyard for the purpose. A vineyard of pedigreed vines of all our most desirable varieties would be a most valuable acquisition for the State. Such a vineyard might be started with cuttings selected in the way described, and each variety gradually brought up to its highest possible bearing capacity, by grafting all the vines of each variety with cuttings taken from the vine of that variety which had shown the best and most regular bearing qualities during a term of years. Twenty-five or thirty such vines of each variety would be suffi- cient to maintain and improve the productiveness of all the vineyards in the State if it were used to supply stock to nurserymen and other growers of vine cuttings. This would make it unnecessary to abandon many of the finest varieties of grapes, as has been done to a great ex- tent lately. Part of the Vine. While any cutting from a good vine is probably better than the best cutting from a poor vine, it is not a matter of in- difference from what part of the vine the cuttings are taken. It. is a well established fact known to all skilled pruners that certain buds on a vine are much more likely to produce fruit than others. These buds may be called, from analogy with similar bud on orchard trees, fruit buds. The fruit buds of vines, unlike those of most orchard trees, are not distinguishable by shape or size from wood or sterile buds. They can be recognized only by their position. The buds on suckers (canes from below the ground) or water- sprouts (canes from the trunk or older parts of the arms) are usually unfruitful with most varieties. The only buds which can be depended on to give fruit are those on canes which have grown on wood of the previous year, or as pruners usually express it, * ' fruit spurs and fruit canes consist of one-year-old wood growing out of two-year-old wood. ' ' The canes of such wood are called by the grape-growers of South Af- rica "bearers," and no others are used for making cuttings. Now, while the choice of this wood is perfectly safe, it has not been demonstrated that such choice is necessary. It may be that cuttings taken from heavy bearing vines will grow into other heavy bearing vines whether they have originally been water-sprouts or fruit wood. This seems probable, for in pruning vines it is constantly necessary to use water-sprouts to form spurs for the purpose of replacing lost arms or for shortening arms which have grown too long. Now, while these spurs bear little or no fruit the first year, they give rise to wood the following year, which satisfies the primer's definition of fruit wood, viz., "one-year-old wood out of two-year-old wood," and which is ap- parently as fruitful as any wood on the vine. A sucker, or water- sprout from a fruitful vine, therefore, is to be preferred in making cuttings to a fruit cane from a vine which bears small crops. All canes and all parts of the cane, however, are not equally suit- able for cuttings. Very small, thin canes are apt to be ill-nourished and immature, as are also the tips of better canes. Many cuttings made from such material are apt to fail, or give weak vines. Very large, over-grown cuttings are also to be avoided. Many growers avoid using the two or three buds nearest the base of the cane on the ground that such buds are not fruit buds, but the same reasoning may be ap- plied to this case as to that of water-sprouts. A medium sized cutting between three-eighths and five-eighths inches in diameter is most likely to give good results. Form and Length of Cutting. It was formerly considered good practice to leave a piece of old wood attached to the base of the cut- ting, on the ground that such cuttings always grew. This practice is now very generally abandoned, as it often gives rise to weak and dis- eased vines. The piece of old wood always decays finally, and the decay may spread into the trunk and roots of the vine. A good cut- ting should consist exclusively of one-year-old wood ; that is, the wood which has grown during the current season. The form and length of the cuttings will depend on the use that is to be made of them. If they are to be used as scions for grafting they may be cut up in any way and of any length that is found convenient for handling and keeping them in good condition. If they are to be used for rooting either in the nursery or the vineyard it is most con- venient to cut them up into the exact lengths which are to be planted. The length will depend altogether on the soil and climate where they are to be planted. They should be of such a length that when planted the base of the cutting will be at the level where the conditions are most favorable to root formation. If the base is too deep, it will be too wet and too cold to develop roots. Roots will start higher up and the bottom part will be wasted, or worse still, may decay and injure the vine. If the base is too near the surface the whole cutting may dry out and die before its roots have developed sufficiently to supply it with water. In the moister soils of the cooler districts a cutting 10 inches long is sufficient for direct planting in the vineyard. In the drier and warmer interior a 14- to 16-inch cutting is better, while in the driest soils of the warmest districts it is often necessary to have a cutting 18 to 20 inches long. For planting in the nursery a 12- or 14-inch cutting is about the most convenient. If the soil of the nursery is wet and cold more of the cutting should be left above ground; if, on the contrary, the soil tends to be hot and dry the cutting must be planted deeper and even covered up completely. It is not necessary, or possible, to make every cutting of exactly the same length, because they should all terminate at each end at a node. A vine cane consists of nodes where the buds are and internodes be- tween the buds. The pith is interrupted at each node by a woody par- tition which extends through the cane at each bud. In making a cut- ting, therefore, we should cut exactly through a bud both at the top and at the bottom. This will leave the woody partitions, which will prevent decay at the bottom and drying out at the top. Conservation of Cuttings. In some cases vine cuttings may be planted with success as soon as they are made. This can be done only in light, well-drained soils where there is no danger of the ground be- coming water-logged and remaining in this condition for some time. Except in such cases it is better to defer the planting of the cuttings until most of the winter rains are over and the soil commences to warm up in the Spring. To preserve the cuttings in good condition until this time they must be kept from drying out or being injured by too much moisture. If they are buried in sand or loose soil in such a way that at least the butts are in contact with the soil they will keep well until April. The sand should be comparatively dry and well sifted in to the centers of the bundles of cuttings. These bundles should be small and if they are to remain in the sand for more than two weeks they should be loosely tied, or better still, not tied at all, but simply buried in thin layers. Unless the sand is in contact with the cuttings nearly every- where, many will dry out and die if the sand is dry, or they will mold and decay if the sand is moist. A good place to bury the cuttings is a shed or cellar or on the north side of a building. If such a place is unobtainable they may be put in a hole at least as deep as the cuttings and covered up well with soil. Over this soil should be placed a thick bed of straw, or other material, to prevent the soil drying or becoming too warm. This last precaution is particularly necessary if the planting is to be delayed until late Spring, for otherwise the buds and roots may start. Cuttings which have started slightly before being planted will often grow, but they do not make the best growth. Above all, the cuttings must be protected from too much moisture. A cutting injured by being kept too wet is useless, while one kept a little too dry will give good plants if soaked in water for a day or two before being planted. Definition of Good Vine Cuttings. They should be : 1. Taken from a healthy vine which has borne good crops regularly. 2. Of medium size, one-third to two-thirds inch in diameter. 3. Made from bearing wood (?). 4. Well ripened, as shown by firmness of wood, light colored pith and well- formed buds. 5. Healthy, as shown by clear, uniform color. 6. Medium jointed (length of joints varying according to variety). 7. Moist. It should be possible to squeeze out a little sap from a newly made cut. 8. Uninjured by too much moisture. The pith should not have turned black or the bark have become loose. 9. Of the length most suited to the place where they are to be planted. 10. Cut through a bud both at top and bottom. PUBLICATIONS. COLLEGE OF AGRICULTURE, AGRICULTURAL EXPERIMENT STATION RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION, BY FREDERIC T. BIOLETTI. Vineyard of Bench-grafts. One failed out of 750 planted. BULLETIN No. 180. W. W. SHANNON, SACRAMENTO: SUPERINTENDENT STATE PRINTING 1906. BENJAMIN IDE WHEELER, Ph.D.,LL.D., President of the University, EXPERIMENT STATION STAFF. E. J. WICKSON, M.A., Acting Director and Horticulturist. E. W. HILGARD, Ph.D., LL.D., Chemist. W. A. SETCHELL, Ph.D., Botanist. ELWOOD MEAD, M.S., C.E., Irrigation Engineer. C. W. WOODWORTH, M.S., Entomologist. R. H. LOUGHRIDGE, Ph.D., Agricultural Geologist and Soil Physicist. (Soils and Alkali .) (Ab- M. E. JAFFA, M.S., Chemist. (Foods, Nutrition.) [sent on leave.) G. W. SHAW, M.A., Ph.D., Chemist. (Cereals, Oils, Beet-Sugar.) GEORGE E. COLBY, M.S., Chemist. (Fruits, Waters, Insecticides) RALPH E. SMITH, B.S., Plant Pathologist. A. R. WARD, B.S.A., D.V.M., Veterinarian and Bacteriologist. E. W. MAJOR, B.Agr., Animal Industry. F. T. BIOLETTI, M.S., Viticulturist. (Grapes, Wine, and Zymology.) H. M. HALL, M.S., Assistant Botanist. JOHN S. BURD, B.S., Chemist, in charge of Fertilizer Control. C. M. HARING, D.V.M., Assistant Veterinarian and Bacteriologist. ALBERT M. WEST, B.S., Assistant Plant Pathologist. E. H. SMITH, M.S., Assistant Plant Pathologist. G. R. STEWART, Student Assistant in Station Laboratory. , Assistant in Soil Laboratory. RALPH BENTON, B.S., Assistant in Entomology. LUDWIG ROSENSTEIN, Laboratory Assistant in Fertilizer Control. ALFRED TOURNIER, Assistant in Viticulture. HANS HOLM, Student Assistant in Zymology. A. J. GAUMITZ, Assistant in Cereal Laboratory. J. C. BRADLEY, A.B., Assistant in Entomology. D. L. BUNNELL, Clerk to the Director. R. E. MANSELL, Foreman of Central Station Grounds. JOHN TUOHY, Patron, ) , > Tulare Substation, Tulare. , Foreman, ) J. W. MILLS, Pomona, in charge Cooperative Experiments in Southern California. J. W. ROPER, Patron, ) > University Forestry Station, Chico. E. C. MILLER In charge, ) > University Forestry Station, Santa Monica. N. D. INGHAM, Foreman, ) VINCENT J. HUNTLEY, Foreman of California Poultry Experiment Station, Petaluma. The Station publications (REPORTS AND BULLETINS), so long as avail- able, will be sent to any citizen of the State on application. CONTENTS. PAGB. INTRODUCTION - 89 I. THE NURSERY Choice and preparation of the soil. 93 Grafting cuttings. . - 94 Choice of cuttings -.. 94 Mother vines . --. 95 Making and conservation of cuttings 98 Time of grafting _ 100 Preparation of stocks 100 Preparation of scions 102 Grading cuttings . 102 Methods of uniting stock and scion 106 Tongue grafting 108 Wire grafting 110 Making bundles 111 Grafting rooted cuttings .: 112 Callusing 113 Planting in the nursery 118 Cultivation in the nursery 121 Removal of scion roots ...- _ 124 Removal of raffia and suckers ..- 124 Digging the grafts 125 Sorting the grafts ... 125 Pruning the grafts --. 126 Conservation and shipping 128 Nursery grafting 128 II. THE VINEYARD- Preparation of the soil 129 Fertilization 129 Intercalary crops 130 Planting _ _ .- 130 Pruning 133 Staking 133 Suckering and rooting '. _ 134 Cultivation.. 134 Ixxxviii CONTEXTS. HI. FIELD GRAFTING PAGE. Preparation of the soil .. 135 Cuttings or roots - 135 Age for grafting . 136 Methods of grafting 136 Tying and waxing 138 Season for field grafting 138 Treatment the first year.. . .. 138 Regrafting 139 Herbaceous grafting 140 Comparison of various methods 142 ILLUSTRATIONS. Young vineyard of bench-grafts .- ^ (cover) FIG. 1. Effect of scion roots on old vines . 92 2. Mother vines of resistant stock. . 99 3. Gauge for cutting stocks 101 4. Notch and slot graders 103 5. Slot grader setup 103 6. Scales for slot grader 105 7. Various methods of bench grafting 107 8. Method of holding knife .. 108 9. Wire-cutter 110 10. Bundle stand 111 11. Callusing bed . 113 12. Plan of callusing bed 114 13. Callused wire graft : 114 14. Effects of moisture on callus formation 115 15. Root and callus formation 116 16. Effect of temperature on callus formation 117 17. Callused whip grafts 118 18. Planting dibbles 120 19. Method of planting in nursery with dibble... 121 20. Method of planting in nursery in trenches 121 21. Irrigating a nursery. 122 22. Scion roots on bench grafts. 123 23. Grafts strangled by raffia. 125 24. No. 1 bench grafts 127 25. Method of planting grafts in vineyard. 131 26. Methods of field grafting 137 27. Scion roots in field-grafted vine.. 139 28. Herbaceous graft 140 29. Herbaceous bud .... ...'... 141 RESISTANT VINEYARDS. GRAFTING, PLANTING, AND CULTIVATION. BY FREDERIC T. BIOLETTI. INTRODUCTION. There is no subject connected with grape-growing about which there is more general demand for information in California than that of the growing of resistant vines. Innumerable inquiries are received at the Experiment Station regarding methods of planting, grafting, and cultivating phylloxera-resistant vineyards. Several bulletins on various phases of this subject have been published by the Station, but they are all somewhat out of date at this time, and the editions of most of them are exhausted. The two phases of the subject about which there seems to be most pressing need for information are the determination of the best varieties of resistant stocks for the various soils and climates of the State, and the best methods of starting and grafting a resistant vineyard. With regard to the first phase, the Station is carrying on tests in various localities and is gradually accumulating data which will make it possible to offer some definite recommendations at a future time. The questions of adaptation to local conditions and of affinity between stocks and scions of various varieties are complicated and difficult, and require much time and experimentation for their completely satisfac- tory solution. With regard to the second phase we have a great deal of valuable evidence drawn from the experience of growers during the last twenty years and from experiment work conducted by the Station. Though there is always room for improvement, we may say that the methods of our most progressive growers of resistant vineyards are perfectly successful in accomplishing the object in view. Unfortunately many growers are not so successful, and many of the resistant vineyards of the State are an eyesore and a source of loss to their owners. It is from such growers that originates the statement that resistant vineyards are a failure. Growers who have adopted proper methods of handling resistant vineyards are enthusiastic in their praise. It has been demon- strated here, as in Europe, that, as a rule, vineyards of vinifera vines 90 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. grafted on resistant stock, when properly handled, produce larger crops of better grapes than vineyards of ungrafted vinifera. This bulletin is issued, therefore, with the object of describing what seem to us the best methods of procedure, especially as regards the mechanical details of grafting, planting, and nursery work. Some of the chief causes of failure in unsuccessful grafted vineyards are: 1. The use of a resistant variety which is unsuited to the soil and climate of the locality. Resistant varieties are all derived from one of several species of wild vines indigenous to the United States east of the Rocky Mountains. All these species are much more difficult to suit in the matters of soil and climate than the European wild vine, Vitis vinifera, from which all our wine and raisin and most of our table grapes are derived. This question of adaptation to local conditions is only touched on here. 2. The use of an insufficiently resistant variety. Varieties of all degrees of resistance exist, from almost absolute immunity to a degree of resistance so small as to be of little practical value. Some with a medium degree of resistance, like the Lenoir, will give fair to good results when grown under the most favorable conditions, but fail more or less completely when attacked by phylloxera under less favorable conditions. This question of resistance is not discussed fully here, but all the varieties recommended have sufficient resistance under prac- tically all conditions that exist in Californian grape-growing districts. 3. The use of unselected resistants. Many of the first resistant vine- yards started in California were planted with cuttings of wild Riparia vines collected in Nebraska and other native habitats of the species. Wild vines are nearly always seedlings and, therefore, vary very much. Each vine, though of the same wild species, is in fact a different variety of the species (using the word variety in the horticultural sense). For this reason, wild vines differ greatly in many respects, and especially in the important character of vigor. Though a few of them may be sufficiently vigorous to make good grafting stock, many of them are much too weak or slender, and none of them are likely to be as good as the best named varieties which have been selected from a vast number of seedlings on account of their exceptional vigor and the possession of the greatest number of those characteristics which are desirable in a grafting stock. Most of the earlier resistant vineyards show great variation in the vigor and bearing of the vines due to this use of wild cuttings, and none of them give as good results as they would have given if grafted on a good selected variety of stock. This variation in vigor, bearing, and longevity is often found in more modern vine- yards, and is due to a mixing of varieties by the nurseryman or the grower of resistant cuttings. RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 91 4. Grafting the resistant vines when too old. A grafted vine to be a permanent success must have a perfect union. The younger the tissues, the more complete and lasting the union. Budding and graft- ing herbaceous canes produce unions which are practically perfect. If the scion and stock are each only one year old, as in cutting grafting, the union is nearly always as perfect and permanent. No wood older than one year is ever used as a scion, but the stock is often grafted when much older. If the stock is more than one year old many varie- ties fail to give good unions, and if three or four years old a large number of the grafted vines will fail after they have produced a few crops. Some of the best resistant stocks fail almost completely if grafted when several years old, and though they bear well and appear strong for a few years they soon begin to fail, and every year after the first two or three crops a certain proportion of the unions fail and the tops die. A vineyard may linger in this way for eight or ten years, until finally from 50 to 75 per cent of the vines are dead. This is one of the strongest objections to field grafting, and is more thoroughly discussed later. 5. Planting or grafting too deep. The result of this is that the scions form their own roots and finally become independent of the resistant stock, which dies. Such vines are, of course, non-resistants and just as quickly killed by phylloxera as if grown in the first place from vinifera cuttings. Some vine-growers, of long experience with vinifera vine- yards but unfamiliar with resistants, do not believe that this death of the resistant stock will take place under the conditions described. They state that it is an advantage for the scion to have its own roots as well as those of the resistant. They argue that, if there is little or no phylloxera present, the vines will do better with two sets of roots than with one, and that, when the phylloxera increases to dangerous propor- tions and destroys the vinifera roots, the resistant roots are there to save the vine. This theory is based on the false assumption that the roots are the main, or only, feeding organs of a plant, and overlooks the fact that the roots require the materials furnished by the leaves quite as much as the leaves require those furnished by the roots. For both to be vigorous, therefore, there must be a mutual exchange of food matters. This exchange takes place through the medium of the tubes and cells of the wood and bast of the stem of the vine. The soil nutrients pass with the sap, principally through the younger wood, from the roots to the leaves. In the leaves these materials are combined with -gases absorbed from the air and are elaborated into the real food of the vine which passes back, principally through the bast or region exterior to the wood, into all parts of the plant, to supply the material necessary for growth and other various vital functions. 92 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. In ungrafted vines this exchange takes place readily and all the branches and all the roots are well nourished. In grafted vines, owing to the fact that the stock and scion are of different species and, there- fore, of different structure and composition, there is some interference with the exchange, resulting in a slight weakening of the whole vine. This weakening, under proper conditions, is so slight that it does not FIG. 1. Showing effect on Resistant Stock of allowing the scion roots to remain. (Redrawn after Viala and Ravaz.) A. Old grafted vine with large top roots (S) from scion. Note small, weak resistant stock (R). B. Normal grafted vine on which no scion roots have been allowed to develop. Note smooth union (U) and strong resistant stock (R). detract from the usefulness of the vine, and, in fact, like many other slightly weakening causes, it usually has the effect of producing an increased tendency to fruitfulness. If, however, the scion is allowed to make its own roots, the return stream of nutritive material takes the course of least resistance and goes principally into the scion roots. The result is that these grow vigorously, so long as the phylloxera is absent, and the roots of the resistant stock are starved and finally die. This RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 93 is not mere theory, but is substantiated by the numerous cases where dying resistant vineyards have been examined and this condition found. This condition is particularly common with field-grafted vines. There are several ways in which the union between resistant stock and bearing scion can be brought about: (1) The scion cuttings may be grafted on the resistant cuttings or on resistant roots in the work- shop before planting in the nursery. This is called "bench grafting." (2) The resistant cuttings may first be rooted in the nursery and then the next year grafted in place without removal. This is called "nursery grafting." (3) The resistant cuttings or roots may be planted directly in the vineyard and then the next year or some subsequent year they may be grafted. This is called "field grafting," "vineyard grafting," or "grafting in situ." Each method has its advocates and its uses, but the. method of most general application and that which has given the most general satisfac- tion is the first. The last method is practised with success only where the conditions are exceptionally favorable, and even there is gradually being rejected in favor of the first by nearly every grower who has tried both methods. The reasons for this will be discussed after the various methods have been described. I. THE NURSERY. Choice and Preparation of the Soil. The high cost of grafted vines is due partly to the skill and labor necessary in producing them, but, also, in a great degree, to the large number of grafts which fail to grow or to make a satisfactory union in the nursery. If we allow $10 per thousand for the cuttings used as stock and scion, and $15 per thousand for making and growing the grafts, they could be raised profitably for $35 per thousand if every one grew and made a good grafted vine. Probably on the average not more than fifty per cent of the grafts made are sufficiently perfect in growth, union, and root to be sold, and they must therefore bring $60 or more per thousand to be raised at a profit. While there are many causes for the failure of some of the grafts to grow, probably the most important of these is the nature of the soil in which they are rooted. Any soil which bakes on the top after rain or irrigation will cause the failure of many grafts. If the crust is not broken up, the moisture will escape and the scions dry out. If the crust is broken, many of the scions will be disturbed and fail to unite. A soil which becomes very compact will spoil many grafts by preventing the shoot from pushing its way through. Stony soils destroy many grafts in similar ways. If the soil dries out too easily and quickly many scions will fail to unite. Wet soils are even worse. A soil which remains 94 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. cold and wet for any considerable time after the grafts are planted will cause the loss of a large proportion. The ideal soil for a nursery of bench grafts is a light, well-drained, sandy loam containing an abundance of humus. It should be carefully graded in order to have no low spots where the water will lie and drown the grafts, and no high spots to which it is difficult to get the irrigation water. The physical nature and condition of the soil is of more importance than its chemical composition. The soil should not be poor, but it is, on the other hand, not desirable that it should be too rich. Grafts which grow very large in the nursery do not make the best vines in the vineyard. Extra large grafts often die the first year after they are planted out. Small dwarfed grafts are a year behind those which are well grown, and probably never make profitable vines. A plant of medium size, with good roots, perfect union, and a growth of from 15 to 18 inches, is the best. At least two months before planting, the soil of the nursery should be thoroughly prepared. All weeds, stones, and rubbish should be removed and the ground well plowed. Most soils should be plowed or subsoiled to a depth of at least 18 inches in order to aerate and pulver- ize the soil to promote quick rooting. Unless the roots of the stock start almost as soon as the buds of the scion, the latter will dry out as soon as its little leaves begin to evaporate water. If the subsoil is clayey or contains a great deal of cementing material, it should not be turned up. Soils which are defective, if used at all, should, of course, be fertilized. Any fertilizer which improves the texture of the soil is to be preferred. Well-rotted stable manure is useful, but the best fertilizer for the purpose is a good crop of field peas or other legume plowed-in the previous autumn sufficiently early to insure its complete rotting before planting time. Cutting Grafts. Choice of Cuttings. To obtain the best results, ooth in the percentage and quality of the grafted vines produced by the nursery and in the profit of the vineyard where they are planted, great care is necessary in the selection of cuttings for both scions and stocks. For scions, cuttings should be taken only from healthy vines which are known to have produced good crops. Cuttings from vines weakened by phylloxera, root-rot, or other diseases are apt to be weak, soft, badly nourished, and incompletely matured. Such cuttings will not give a high percentage of No. 1 grafts, nor make a profitable vineyard. Cut- tings showing signs of serious attacks of oidium, vine-hoppers, or other fungi and insects should be rejected. The cuttings used should be of RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 95 medium size, firm, with small, light-colored pith and short to medium joints. Very large or very small cuttings do not give the largest per- centage of successful unions, nor the best vines. The best size is about one third of an inch in diameter, though this will vary somewhat according to the variety of vine. Any cuttings under one quarter of an inch or over one half an inch in diameter should not be used. If this rule is adopted, all buds from the thick base of the cane which are apt to give unfruitful vines, and all buds from the tip of the cane which are apt to be immature and to give weak vines, will be eliminated. The choice of cuttings for stocks is almost equally Important. All the precautions regarding the health and maturity of the cuttings and of the vines from which they come apply equally in this case. The most important point to be observed, however, is that they are unmixed and true to name. If there is a slight mixture of varieties in the scion cuttings the error is not quite so serious, as the grapes may be nearly equally valuable, and at worst the vines can be regrafted. If the stocks are mixed, however, there is no easy way of detecting it, and the result will probably be a vineyard of unequal growth, in which many of the vines are unprofitable. There is great danger of this mixing of stocks, for many vineyards of mother vines in California are badly mixed with many inferior kinds of Riparia, Rupestris, etc., most of which are valueless as grafting stock. The conditions in France seem to be no better, and the risk of a mixture in imported cuttings is greater than with the home-grown, as we have no opportunity of verifying the mother vines and are quite at the mercy of the nurseryman. The size of the stock cuttings must, of course, be the same as that of the scions, as they have to be accurately matched. The cuttings should be smooth and straight. Crooks, curved cuttings, with large knots where laterals have been removed, are much more difficult to graft. It is to be desired that some one would make a business of raising mother vines for the production of cuttings for grafting. It would be a profitable crop, and if properly looked after would much improve the quality and lessen the cost of grafted vines. Planting and Cultivation of Mother Vines. In planting a vineyard of resistant vines for the production of cuttings to be used for grafting it is important that a suitable soil and location be chosen. In order to produce a large crop of good cuttings the soil should be naturally rich or heavily fertilized. The location should be one in which the wood always ripens early and thoroughly. Spring frosts are almost as unfavorable to the production of good cuttings as of grapes. The choice of varieties to plant will depend, of course, on what the market demands. If there should be a falling oft of the demand for 96 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. the kind planted, or an overproduction, it is always possible to graft the stocks with other varieties of resistants to meet the changed conditions. For the best results the land should be given the same careful preparation recommended for the planting of grafts. (See page 93.) All the usual stocks are vigorous growers, and as they are planted in fertile soil they should be given plenty of space. A distance of 9 feet by 9 feet or 8 feet by 10 feet is quite close enough. This will give about 500 vines to the acre. As a good vine properly cared for should produce 150 feet of good wood for bench grafting, the product of an acre would be about 75,000 cuttings. The varieties of resistant stocks which will in all probability be most used in California are Rupestris St. George (du Lot), Riparia X Rupes- tris 3306, Riparia X Rupestris 3309, Riparia Solonis 16.16, Mourvedre X Rupestris 1202, Aramon X Rupestris 2, Riparia gloire, and Riparia grande glabre. These are all varieties which have given excellent results for years in Europe, and have all been tested successfully in California. Among them are varieties suitable for nearly all the vineyard soils of California, with perhaps the exception of some of the heavier clays. The only one of these varieties which has been planted extensively in California is the Rupestris St. George. There can be little doubt, however, that it will fail to give satisfaction in many soils, and though we may not find something better for all our soils it is probable that we will repeat the experience of Southern France and find that in most soils there is some other variety that gives better results. Without attempting to describe these varieties, but to give some idea of their merits and defects and of' the soils most suited to each, the following indications are given, based principally on the opinions of L. Ravaz and Prosper Gervais, and on a still limited experience in California : The Rupestris St. George is remarkably vigorous and grows very large, supporting the graft well even without stakes. It roots easily and makes excellent unions with most vinifera varieties. It is well suited to deep soils where its roots can penetrate. Its defects are that it is very subject to root-rot, especially in moist soils; it suckers badly and it suffers from drought in shallow soils. Its great vigor produces coulure with some varieties and often necessitates long pruning. In moist or wet soils 1616 or 3306 have given better results in France and give indications of doing equally well here. In drier soils 3309 will probably be found preferable. Aramon Rupestris No. 2 is suited to the same soils as Rupestris St. George, and does particularly well in extremely gravelly soils. It has some of the defects of the St. George and is moreover more difficult to graft, and its only advantage in California is that it is rather less susceptible to root-rot. RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 97 There are no better resistant stocks than Riparia gloire and Riparia grande glabre, wherever they are put in soils that suit them. They do well, however, only in deep, rich, alluvial soils which are neither too wet nor too dry. Their grafts are the most productive of all, and ripen their grapes from one to two weeks earlier than the grafts on St. George. Their principal defect is that they are very particular as to the soil, and they never grow quite as large as the scion. The gloire is the most vigorous, and the difference of diameter is less with this variety than with any other Riparia. The Mourvedre X Rupestris 1202 is extremely vigorous, roots and grafts easily, and is well adapted to rich, sandy and moist soils. In drier and poorer soils its resistance is perhaps not sufficient. The most promising varieties for general use at present seem to be the two hybrids of Riparia and Rupestris, 3306 and 3309. They have great resistance to the phylloxera, root and graft almost as easily as St. George, and are quite sufficiently vigorous to support any variety of vinifera. The former is more suited to the moister soils and wherever there is danger of root-rot, and the latter to the drier soils. In general, they are suited to a larger variety of soils and conditions than perhaps any other varieties. Riparia gloire should be planted only on rich, deep alluvial soil containing an abundance of plant food and humus, what would be called good garden land, such as river bank soil not liable to overflow. In most other soils Riparia X Rupestris 3306 is to be recommended, except those which are rather dry, where 3309 is to be preferred, or those which are very wet, where Solonis X Riparia 1616 is surer to give good results. The methods of pruning and training mother vines of resistant varieties will differ in several important respects from the methods suitable for varieties grown for their fruit. In the latter case we should be careful to leave as many fruitful buds as the vine can utilize; in the former the fruit is of no value, and if any is produced it will be at the expense of the wood. Our object is to produce as much wood as possible. In accordance with this idea the mother vines are often pruned in such a way as to force out each year a growth of watersprouts from the old wood. All the canes on the vine are cut off as close to the stump as possible. It is doubtful if this is the best way. So many watersprouts are forced out that the labor and care of thinning them are expensive. If they are not thinned there is a large growth of wood, but the canes produced are short and thin, and, therefore, unsuitable for grafting stock. If this method is adopted from the beginning the vine is 98 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. reduced to a prostrate stump, which makes cultivation difficult, and as the vine becomes old it becomes full of dead wood and difficult to prune. A better method is to give the vine a trunk and head exactly as in pruning ordinary vase-formed vines. A trunk from 15 to 18 inches high and with five or six arms will make a vine much easier to cultivate and prune and at least equally productive of good cuttings. In pruning, very short spurs are left, consisting simply of the base bud. The cane should be cut off through the first bud above the base bud. This will insure the starting of the base bud and will avoid the danger of injury which occurs when the cut is made too close to the bud which we desire to have grow. With this method of pruning the arms will lengthen so slowly that there will never be occasion to cut them back. During the spring and early summer all unnecessary shoots should be removed in order to throw all the vigor of the vine into those which remain. A good, strong vine in rich soil should produce from 150 to 300 feet of good grafting wood between one quarter and one half of an inch in diameter, and a certain amount of smaller wood good for rooting. Experience only will tell how many shoots should be left to a vine. It will depend on the age of the vine, the variety and the soil. If too few are left there is apt to be too much thick wood unsuitable for grafting, especially with certain varieties such as Rupestris St. George. If too many are left there will be too many small cuttings. Some varieties of stocks produce good grafting wood if the canes are allowed to grow over the surface of the ground without support. This has a tendency with some varieties to encourage the growth of laterals and to make the canes short and stocky. To overcome this defect high poles are sometimes placed at each vine, and the canes kept in an upright position by being tied to these poles. The poles are sometimes 15 or 20 feet high. This method produces an abundance of excellent grafting cuttings, but is expensive and troublesome. A more practical method is to put a high stake 10 ieet high at the end of each row and to stretch a wire at that height along the row. The shoots are then trained up to this wire by means of strings renewed every year. (See Fig. 2.) Making and Conservation of Cuttings. Cuttings for grafting, to be used either as stocks or scions, may be taken from the vines at any time between the fall of the leaves in the autumn and two weeks before the swelling of the buds in the spring. They may be used as soon as made, or kept for an indefinite time, provided they are given proper care. RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 99 It is usually more convenient to take the canes from the vines, place them in an outhouse or shed, and make them up into cuttings in rainy weather. In a shed they may be left without protection for a couple of weeks, but it is best not to leave them longer, especially in dry weather. The scion cuttings are conveniently cut in lengths of from 18 inches to 3 feet, and tied in bundles of 100 to 250 if they are to be transported to a distance. They should be tied up in such a way that the butte of all of them are even ; this will prevent any of them drying out when FIG. 2. Mother vines of resistant stock. (From catalog of F. Richter, Montpellier.) they are heeled in. If they are to be kept for grafting where cut, should be made into loosely tied small bundles, which should be well covered with loose soil or sand, care being taken to cause some of the sand to fall in among the cuttings in the center of the bundle. They may be heeled in outside in some place protected from the sun and from water. They are safer, however, and will remain dormant longer if placed in a sand pile under a shed or in an underground cellar. There should be a few inches of sand both under and above the cuttings. The sand in which the cuttings are placed should be fairly dry. If too dry the cuttings may die, but the chief danger is that it will be too wet, in which case they will rot. The sand should not contain more than five per cent of moisture. With less than this amount it will not 100 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. feel moist to the hand. If a handful of sand is taken it should not form o ball when squeezed and should not leave the hand moist. There is very little danger of getting the sand too dry, unless it is taken from the top of a pile which has been exposed to the hot sun for several days. An ideal method of keeping cuttings is to cover them with a mixture of dry moss and a little powdered charcoal in a cool, moist cellar. The cuttings should be loose or in small bundles in order that they may all be in contact with the moss. Cuttings to be used as stocks should be handled in the same way, except that it is preferable to cut them up into the lengths which will be used. The length will vary from 8 to 15 inches, according to whether long- or short-grafted plants are panted. For planting in very dry soils which are very open and liable to dry down deep, and for hillsides where the unions must be placed higher, long grafts are desirable. As a rule, a cutting of 10 inches is quite long enough for grafting. Longer cuttings are more difficult to handle in the nursery, and shorter cuttings require more care in the vineyard. The stock cuttings should be kept dormant like the scions, but a slight swelling of the buds is not so serious in this case. If the scion buds have commenced to swell they should not be used, as there will be too many fail to grow. If the stocks have started a little they can still be used successfully, provided that the bark has not become loose. Time of Grafting. Cutting grafting may be commenced in California by the first of January, or even sooner, but the best results are obtained by grafting in February and March. The work may be continued through April and even in May if the cuttings can be kept dormant. Preparation of Stocks. The first thing to do when everything is ready for grafting is to prepare the stocks. If it has not already been, done the resistant cuttings should be cut into the desired lengths say 10 inches. This should be done as accurately as possible, and some kind of gauge will be needed. This gauge may be simply marks cut in the work table, or a stick of the required length held in the hand. The cut at the bottom should be made through a bud in such a way as to leave the diaphragm or partition which interrupts the pith at this place. The top cut should then be made as near 10 inches from the bottom as is possible, while at the same time leaving at least 1% inches of internode above the top bud. This piece of intcrnode is necessary for convenience in grafting. Fig. 3 shows a simple gauge for insuring accuracy in cutting the stocks. It consists of a piece of 1-inch board 18 inches long and 6 inches wide, to the middle of which is nailed a piece of wood 1 inch RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 101 square in section extending the whole length of the board. - The length of the stock is determined by an adjustable piece of wood 3 inches long placed at right angles to the longitudinal piece. A corner of the board opposite this adjustable piece is cut off in such a way that the outer edge of the board is 1% inches shorter than the other edge. A guide line is then cut in the board parallel with the slanting edge left by the saw and 1% inches from this edge. In using the gauge the base of the cutting is placed against the adjustable piece and the cutting moved backwards or forwards until a bud falls just to the right of the guide line. The cutting is then cut off level with the edge of the board. This gives each stock 1% inches of internode for grafting above the top bud, with a maximum variation of 1% inches in total length. This variation is of little consequence and can not be avoided. Greater variations give trouble in planting. Any inconvenience due to even FIG. 3. Gauge for cutting stocks. this variation may be avoided by sorting the cuttings into two or three lots according to length after cutting, though this sorting is perhaps best deferred until the grafts are made. The next process is the disbudding of the stocks. If this is done properly, it decreases greatly the number of stock suckers which will appear in the nursery and which must be removed. With some varie- ties, such as Riparia, all that is necessary is to cut out the main bud. This is most easily and quickly done with a knife. With other varieties such as the Rupestris St. George, it is necessary to cut more deeply and to remove not only the main bud, but also the woody enlargement at its base containing a number of dormant buds which readily give rise to suckers. This is most easily done with a sharp pair of pruning shears. Every bud on the stock should be removed. It is a mistake to leave the bottom bud, as is sometimes done. This bud is of no use, as rooting takes place just as well without it, and if it forms a sucker, this sucker is the most troublesome of all to remove on account of its position. ' 2 BUL. 180. 102 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Preparation of Scions. A scion may consist of one bud or of two buds. There are many advantages in using one bud, the chief of which is that it makes it possible to have every scion the same length what- ever the length of the internodes. With two-bud scions it is impossible to avoid a difference of 2 or 3 inches in the length, owing to the varia- tions in the distances between the buds. If the scions are of the same length it is possible to have all the unions at the same distance below the surface in the nursery. This is a most important point. The only advantage of two-bud scions is that in ground which bakes on top it is possible to have the top bud above the surface of the ground and yet have the union sufficiently deep to prevent drying out. Where the soil does not bake the scions may be covered up completely and one bud is sufficient. The scions should be cut with about 2% inches of internode below the bud and at least % inch of internode above the top bud. If cut too close, especially with blunt pruning shears, there is danger of injuring the bud. A sharp knife is the best tool for cutting scions. Grading the Cuttings. For the best results the stock should be of exactly the same diameter as the scion. If they differ much they may unite, but the union will usually be imperfect. The more nearly they match in size the more perfect the unions and the larger the percentage of first-class grafts. If the cuttings are not sorted beforehand the grafter loses a great deal of time in looking for scions to fit his stocks. A good deal of this time may be saved if the cuttings are sorted by eye into three lots- large, medium, and small before commencing to graft. This division, however, is not fine enough, and the grafter will still have to waste much time in selection. It is not practicable to grade the cuttings more accurately than this by eye, and some mechanical gauge or calibrator is necessary for greater accuracy. Several forms have been used in practice with success. The commonest form is the notch grader shown at the top of Fig. 4. This consists of a brass plate 12 inches long and 2 inches wide, in which are made six or more notches. Each of these notches differs? from the next nearest by one sixteenth of an inch, and they usually vary from four sixteenths, the smallest, to ten sixteenths, the largest. By the use of this grader the cuttings may be separated into eight or more sizes. These sizes differ from each other by the same absolute amount, i. e., one sixteenth of an inch, but the relative difference in the smaller sizes is greater than in the larger sizes. That is to say, size No. 1 is four sixteenths of an inch in diameter, or four fifths the size of No. 2, which is five sixteenths of an inch, while size No. 7 is ten sixteenths of an inch in diameter, or ten elevenths of size No. 8. The RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 103 greatest accuracy, therefore, is obtained where it is least needed, viz., in the larger sizes. To overcome this objection and also to facilitate the work of sorting, the slot grader shown at the bottom of Fig. 4 was devised at the Experiment Station. This grader consists of a brass plate in which O o o o o o Sca> FIG. 4. GRADERS. Notch Grader, above. Each notch is of the width indicated by the corresponding number, which represents sixteenths of an inch. Slot Grader, below. Width of slot at e, % inch; at a, j inch. Length of slot from e to a, 7 inches. is cut a tapering slot terminated at each end by circular enlargements* Fig. 4 shows the exact dimensions and Fig. 5 the general appearance of the grader. The brass plate is screwed on to a wooden block in which is cut a groove three fourths of an inch deep and corresponding to the slot in the plate. The cuttings are graded by inserting the end FIG. 5. Slot grader mounted on a wooden block. which is to be grafted in the wide end of the slot and then passing it along the slot until it can go no farther. Cuttings over one half of an inch in diameter will not enter the slot, while those under one fourth of an inch will pass completely through. Cuttings of dimensions between these two extremes will stop the nearer the large end of the slot the thicker they are. In order to grade them into various sizes, therefore, all that is necessary is to mark lines on the brass plate, or, better, on 104 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. the top of the wooden block, and to sort them into boxes according to the position in the slot where they come to rest. The nearer we place the lines the more grades of cuttings we will have and the less varia- tion there will be in each grade. Fig. 6 shows the various positions of the lines to make four, five, or six grades of the cuttings between 14 and % inch in diameter. To construct the grader the only measure- ments needed are the length from a to e (1 inches) and the width at e (1/2 inch) and at a (^ inch). The scale can be cut with a chisel on the block and the place of the lines determined with sufficient accuracy by means of a rule showing tenths of an inch. The distances between the lines of the three scales have been calculated in such a way that each size bears a certain ratio to the one next to it. The ratios used are .8409, .8705, and .8909, respectively. This means that if we use the first scale each grade of cuttings will average almost exactly five sixths of the diameter of the next larger size. With the second scale the difference will be seven eighths, and with the third eight ninths. Or, looking at it another way, it means that the cuttings in one grade will not vary more than as 5 : 6 in the first case, 7 : 8 in the second, and 8 : 9 in the third. The following table shows the average diameters of the several grades (see Fig 6) : SCALIC T. SCALE 11. SCALE III. .250 in. Size 1 less than .250 in. Size 1 less than .250 in. Size 1 less than Size 2 average Size 3 average Size 4 average Size 5 average .274 in. .325 in. .387 in. .460 in. Size 2 average Size 3 average Size 4 average Size 5 average Size 6 average .269 in. .309 in. .354 in. .407 in. .468 in. Size 2 average Size 3 average Size 4 average Size 5 average Size 6 average Size 7 average .265 in. .298 in. .334 in. .375 in. .426 in. .478 in. Size 6 more than .500 in. Size 7 more than .500 in. Size 8 more than .500 in. If the grader is used according to the directions given below the cuttings will be sorted, if scale I is used, into six sizes. The largest of these will be over % inch and the smallest under % i nc h 5 these should be rejected. The intermediate will then fall into four sizes, which will have the following diameters indicated in the table : Average Extreme Diameter. Variation. Size 2 2736 in. .0473 Size 3 3254 in. .0562 Size 4 3870 in. .0670 Size 5 4603m. .0795 These sizes differ from each other in such a way that the average diameter of each is almost exactly five sixths of that of the next larger O Q) Q) 106 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. size. Or, looking at it another way, the smallest cutting in any grade is just five sixths of the diameter of the largest cutting of the same grade. The green bark or growing layer on small cuttings is thinner than that on large cuttings, but in all it is just about one sixth of the diameter of the whole. If, therefore, the smallest scion of any grade is grafted on the largest stock of the same grade the outer edge of the bark of the scion will be in contact with the inner edge of the bark of the stock. This brings the growing layers sufficiently near to insure the formation of a good union. This, moreover, is an extreme case ; the great majority of the grafts will fit much more nearly than this. Comparing these results with those obtained with the notch grader it will be seen that the cuttings between % i ncn an d % inch are sorted into only four sizes with the slot, while the notches make five sizes of the same cuttings. This reduction of the number of sizes is of some practical advantage, especially as there is no loss of accuracy, but rather a gain, as the smallest sizes vary only as 5 : 6, while those of the notch grader vary as 4 : 5. A practised workman will grade almost as quickly with a notch grader as with the slot, but in the hands of a beginner the latter is much more rapid and accurate. Four grades is the least number that should be made of cuttings between % inch and ^2 inch. With this number some of the cuttings will not fit exactly enough to satisfy some grafters, and a little eye sorting may have to be done while grafting. This sorting by the grafter consumes a great deal of valuable time, and it is better to use a more closely graduated scale if the first does not give satisfaction. The third scale is sufficiently close to satisfy the most particular. In using the grader, every cutting should be measured through its longest diameter or much of the accuracy of the sorting will be lost. The flattening is always on the side toward which the bud points, so that the longest diameter is that at right angles to the one passing through the bud. In using the slot grader, therefore, the cutting should always be held with the bud pointing horizontally. Advantage may be taken of the difference in the two diameters to compensate for the variation in size of cuttings in the same grade. As the cuttings vary as 5 : 6 and the two diameters vary in about the same ratio, the smallest scion cut on the flat side will fit accurately the largest stock cut on the narrow side. The only consequence is a slight angle at the point of union, as shown in Fig. 7, D 1 and 3. Methods of Uniting Stock and Scion. Innumerable methods of cutting and splitting the stocks and scions have been described and recommended. "We will have little difficulty in choosing the best of FIG. 7. THREE METHODS OF BENCH-GRAFTING CUTTINGS. 108 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. these if we remember the fact that any method which brings the grow- ing layers of the two parts of the graft into juxtaposition and keeps them there firmly until they unite will give good results. Among those which fulfill these conditions the best will be those which mutilate the tissues least, leave the least amount of cut surfaces exposed, and are the most easily and rapidly performed. These considerations restrict our choice in bench grafting vines by hand to two methods the tongue, whip, or English cleft, and the wire- graft. Tongue Grafting. When the stocks and scions are prepared and graded the grafter takes a box of stocks and a box of the corresponding size of scions and unites them. Each is cut at the same angle in such a way that when placed together the cut surface of one exactly fits and covers the whole of the cut surface of the other. (See Fig. 7, FIG. H. Showing method of holding the knife and cutting. A 1.) The length of cut surface should be from three to four times the diameter of the cutting, the shorter cut for the larger sizes and the longer for the thinner. This will correspond to an angle of from, 14.5 to 19.5 degrees. The cut should be made with a sliding movement of the knife, as illustrated in Fig 8. This will make the cut more easily and more smoothly. The cut should be made with a single quick motion of the knife. If the first cut is not satisfactory, a completely new one should be made. There should be no paring of the cut, as this will make an irregular or wavy surface and prevent the cuttings coming together closely in all parts. The. tongues are made with a slow, sliding motion of the knife. They are commenced slightly above one third of the distance from the sharp end of the bevel and cut down until the tongue is just a trifle more than one third the length of the cut surface. The tongue should be cut, not split. The knife should not follow the grain of the wood, but should be slanted in such a way that the tongue will be about one half as thick as it would be if made by splitting. Before withdrawing RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 109 the knife it is bent over in order to open out the tongue. This very much facilitates the placing together of stock and scion. (See Fig. 7, A 2, 3.) The stock and scion are now placed together and, if everything has been done properly, there will be no out surface visible and the extremity of neither stock nor scion will project over the cut surface of the other. (See Fig. 7, A 4.) It is much better that the points should not quite reach the bottom of the cut surface than that they should overlap, as the union will be more complete and the scions will be less liable to throw out roots. If the points do overlap, the over- lapping portion should be cut off, as in the Champin grafts. (See Fig. 7, C.) A skillful grafter, by following the above-described method, will make grafts most of which will hold together very firmly. Many of them would fae displaced, however, in subsequent operations, so that it is necessary to tie them. This is done with raffia or waxed string. The only object of the tying is to keep the stock and scion together until they unite by the growth of their own tissues, so that the less material used the better, provided this object is attained. For the formation of healing tissue air is necessary, so that clay, wax, tinfoil, or anything that would exclude the air should not be used. The tying material is passed twice around the point of the scion to hold it down firmly, and then with one or two wide spirals it is carried to the point of the stock, which is fastened firmly with two more turns and the end of the string passed under the last turn. The less string is used the more easily it is removed later in the nursery. (See Fig. 7, A 5 and C 5.) Untreated raffia should be used for late grafts which are to be planted directly out in the nursery, but if the grafts are to be placed first in a callusing bed it is best to bluestone the raffia in order to prevent rotting before the grafts are planted. This is done by steep- ing the bundles of raffia in a three per cent solution of bluestone for a few hours and then hanging them up to dry. Before using, the raffia should be washed quickly in a stream of water in order to remove the bluestone which has crystallized on the outside and which might corrode the graft. Some grafters prefer waxed string for grafting. The string should be strong enough to hold the graft, but thin enough to be broken by hand. No. 18 knitting cotton is a good size. It is waxed by soaking the balls in melted grafting wax for several hours. The string will absorb the wax, and may then be placed on one side until needed. A good wax for this purpose is made by melting together one part of tallow, two parts of beeswax, and three parts of rosin. 110 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Wire Grafting. The merits claimed for this method are that it is more rapid, requires less skill, and does away with the troublesome tying and still more troublesome removal of the tying material. Prac- tised grafters can obtain as large a percentage of No. 1 unions by this method as by any other, and unpractised grafters can do almost as FIG. 9. Wire-cutter. well as practised. Another advantage of the method is that the scions have less tendency to make roots than with the tongue graft. It consists essentially of the use of a short piece of galvanized iron wire inserted in the pith of stock and scion for the purpose of holding them together, thus replacing both tongues and raffia. It has been objected that the iron would have a deleterious effect on the tissues of the graft, corroding them, or causing them to decay. There seems, however, no reason to expect any such result, and vines grafted in this way have been bearing for years without showing any such effect. RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. Ill The preparation and grading of stocks and scions are exactly the same for this method as for the tongue graft. Stock and sqion are cut at an angle of 45 degrees. (See Fig. 7, B 1.) A piece of galvanized iron wire two inches long is then pushed one inch into the firmest pith. (See Fig. 7, B 2.) This will usually be the pith of the stock, but it will depend on the varieties being grafted. The scion is then pushed on to the wire and pressed down until it is in contact with the stock. (See Fig. 7, B 3, 5.) If the cuttings have FIG. 10. Stand for making bundles. large pith it is better to use two pieces of wire, one placed in the stock first and the other in the scion, as shown in Fig. 7, B 4. The length of wire to use will vary with the size and firmness of the cuttings, but 2 inches will usually be found most satisfactory. Wire of No. 17 gauge is the most useful size. Fig. 9 shows a device for rapidly cutting up the wire into the desired lengths. Making Bundles. It the grafts are to be planted out directly in the nursery they may be simply laid in boxes or trays, covered with damp sacks, and carried out to be planted as soon as made. It is usually better, however, to place them for several weeks in a callusing bed before planting. In this case it is necessary for convenience of handling to tie them up into bundles. No more than twenty grafts 112 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION. should be placed in a bundle, and ten is better. If the bundles are too large there is danger of the grafts in the middle becoming moldy or dry. A stand similar to that shown in Fig. 10 is very convenient. It consists of a piece of board 12 inches by 6 inches, on one end of which is nailed a cleat 6 inches by 4 inches and under the other end a support of the same size. Two 4-inch wire nails are driven through the board from below, 4 inches apart and 5 inches from the cleat. Two other 4-inch nails are driven similarly at 1% inches from the other end. The grafts are laid on this stand with the scions resting against the cleat, and are then tied with the two pieces of bluestoned raffia that have previously been placed above each pair of nails. This arrangement insures all the scions, and therefore the unions, being at the same level, and puts both ties below the union where they will not strain the graft. The tying is more expeditious and less liable to disturb the unions than if the bundles are made without a guide. A skillful grafter will make about one hundred tongue grafts on cuttings per hour, or from sixty-five to seventy-five per hour if he does the tying as well. Wire grafts can be made at the rate of two hundred and fifty or more per hour, and by proper division of labor where several grafters are employed this number can be easily exceeded. These esti- mates do not include the preparation and grading of the cuttings. Grafting Rooted Cuttings. Instead of grafting cutting on cutting before rooting, one may graft a scion cutting on a stock cutting which has been rooted in the nursery the previous season. In this way resistant cuttings which are too small to graft become large enough the following year and may be utilized. The principal use of this method, however, is in producing grafts on stocks which root with difficulty, such as Lenoir and Berlandieri. If we make cutting grafts on these varieties the percentage of successes is extremely small, on account of the large number which fail to root. They unite easily, however, with the scion, so that if we defer the grafting until the stock has rooted we save the expense of making a large number of grafts which never grow. With cutting grafts on stocks such as Riparia and Rupestris from 50 to 60 per cent of No. 1 unions is considered an excellent average. With rooted stocks the average should be from 75 to 80 per cent with nearly all stocks. The former method is preferable, however, wherever practicable, as a whole year is saved and the unions on the whole are better. The same methods, tongue or wire graft, may be used with rooted stocks as with cuttings. The only difference lies in the preparation of the stocks. The stocks are cut down to a uniform length as nearly as possible and the scions inserted on the original cutting. The scion RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 113 should not be grafted on to the growth of the previous season, even when it is large enough, as the numerous suckers which would be pro- duced would be very troublesome to remove and would interfere with the uniting. The roots of the stock should be cut back to stubs not more than one inch in length. If left longer they make the handling of the grafts very troublesome and are of little, if any, use. Callusing. When the grafts are made, the cuttings are completely dormant, but as soon as they are placed in the proper favorable con- ditions certain of their tissues become active and the changes and vital processes commence which bring about the rooting of the stock, the sprouting of the scion, and the uniting of one to the other. FIG. 11. Callusing bed. These favorable conditions do not usually exist in the nursery at the time of grafting, so that if the grafts are planted out directly many of them will dry out or be injured by cold and moisture before they can commence active growth. For this reason it is always best, except at the extreme end of the grafting season, to "stratify" the grafts in a " Callusing" bed, where the conditions of moisture, tem- perature, and aeration can be controlled. This callusing bed is usually a pile of clean sand placed on the south side of a wall or building and surrounded by a board partition where there is no possibility of its becoming too wet by the flow of water from a higher level or from an overhanging roof. It should be pro- tected, if necessary, by a surrounding ditch. It should be furnished with a removable cover of canvas or boards to protect it from rain and to enable the temperature to be controlled by the admission or exclusion of the sun's rays. A water-proof wagon-cover, black on one side and white on the other, is excellent for this purpose. 114 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. The bottom of the callusing bed is first covered with 2 or 3 inches of sand. The bundles of grafts are then placed in a row along one end of the bed, and sand well filled in around them. The bundles should be FIG. 12. Plan of Callusing bed. placed in a slightly inclined position with the scions uppermost, and the sand should be dry enough so that it sifts in between the grafts in the bundle. The bundles of grafts are then covered up completely with sand, leaving it at least 2 inches deep above the top of the scion. FIG. 13. Wire graft properly callused. Another row is then placed in the same manner until the bed is full. Finally a layer of 2 or 3 inches of moss or straw is placed over all. (See Figs. 11 and 12.) The callusing bed may be made much deeper and the bundles of grafts laid horizontally in superposed layers. This method economizes FIG. 14. Effect of different amounts of moisture on the production of callus, roots and shoots. A. Cuttings callused in sand containing 15 per cent of moisture. B. Cuttings callused in sand containing 10 per cent of moisture. C. Cuttings callused in sand containing 5 per cent of moisture. D. Cuttings callused in sand containing 2J per cent of moisture. 116 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. room, but makes it difficult to maintain the temperature and moisture conditions regular and uniform in all parts of the bed. In the callusing bed we should endeavor to hasten and perfect the union of stock and scion as much as possible while delaying the start- ing of the buds and the emission of the roots. The latter processes require more moisture than the formation of healing tissue, therefore the sand should be kept comparatively dry. Between 5 and 10 per cent of water in the sand is sufficient. The purer the sand the less water is FIG. 15. Showing the independence of root and callus formation. necessary. There should be a little more moisture present than in the sand used for keeping the cuttings over winter. Too much moisture will stimulate the emission of roots and starting of buds without aiding the callus formation, as is well shown in Fig. 14. The formation of callus, or healing tissue, is a perfectly distinct process from the formation of roots. The independence of these pro- cesses is shown in Fig. 15, where an abundant growth of callus is shown on the cut surface, while roots are shown growing only above the cut surface. RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 117 All the vital processes progress more rapidly when the cuttings are kept warm. To delay them, therefore, we keep the sand cool, and to hasten them we make it warm. In the beginning of the season and up to the middle of March we keep the sand cool. This is done by keeping the bed covered during the day when the sun is shining, and uncovering occasionally at night when there is no fear of rain. If the black-and-white wagon-cover is used the white side should be placed outward to reflect the heat. The temperature should be kept about 60 F. or lower. About the middle of March the temperature of the bed should be raised. This is done by removing the cover during warm days and carefully covering at night. If necessary the layer of moss or straw should be removed on sunny days and then replaced. The temperature 68 F. 77 F. 86 F. FIG. 16. Callus formed at various temperatures in eight days. of the sand at the level of the unions should be about 75 F. during this period. If the temperature rises higher than this there will be a more abundant production of callus, but it will be soft, easily injured, and liable to decay. At the end of four weeks after warming the bed, the union should be well cemented. The callus should not only have formed copiously around the whole circumference of the wound, but it should have acquired a certain amount of toughness due to the formation of fibrous tissue. It should require a pull of several pounds to break the callus and separate stock and scion. When the callus has acquired this quality the grafts are in condition to be planted in the nursery, and may be handled without danger. If taken from the bed while the callus is still soft, many unions will be injured and the grafts will fail, or unite only on one side. If left as long as this in the callus ing bed most of the scion buds will have started and formed white shoots. These shoots, however, 3 BUL. 180. 118 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. should not be more than ~y. 2 to 1 inch long. If they are longer the bed has been kept too wet or too warm. Roots will also have started from the stock, but these also should not be over i/> inch long. The grafts should be handled as carefully as is practicable, but there is no objection to breaking off any scion shoots or stock roots which have grown too long. It is almost impossible to save them, and new ones will start after the grafts are planted, and make a "perfectly satisfactory growth. FIG. 17. Callused whip grafts. (Callus too abundant.) Planting in the Nursery. The grafts are planted in the nursery in rows wide enough apart to allow of horse cultivation, and wide enough apart in the rows to give each graft room to develop. The richer the soil and the better its condition the more grafts may be planted to the acre. The more space each graft is given the larger it will grow. If the grafts are starved either by poverty of the soil or being planted too close they will not only fail to grow vigorously, but the unions will be less perfect and the percentage of No. 1 grafts less. In Europe from 125,000 to 300,000 grafts are planted to the acre. This gives each plant from 20 to 50 square inches of surface. In California the grafts are given more room. The rows can not be placed nearer than 3 feet, and it is more convenient for cultivation to place them 4 feet apart. In most soils the grafts do not give good results if placed closer in the rows than 3 inches apart. In a rich. RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 119 heavily fertilized soil of the best mechanical texture it might be possible to obtain good results at 2 inches, but in many soils it is necessary to place them 4 inches to get good, well-grown plants. The number of grafts to the acre and the space given to each is shown in the following table : Space Between Vines. 2 inches 2 inches 3 inches 3 inches 4 inches 4 inches Rows. 36 inches 48 inches 36 inches 48 inches 36 inches 48 inches Number of Grafts per Acre. 87,120 65,340 58,080 43,560 43,560 32,670 Number of Square Inches per Graft. 72 96 108 144 144 192 The grafts may be planted in a trench made with a spade. It is more economical and better, however, if the soil is of good texture, properly prepared and free from stones, to plant them with a dibble. Whichever way is adopted it is essential that the greatest regularity should be maintained in the alignment of the rows and in the depth of the planting. Before planting with a dibble some form of scraper should be used which will make a shallow ditch from 12 to 18 inches wide and about 2 inches deep, perfectly smooth and level at the bottom. A line is then stretched taut about 1 inch to one side of where the row is to be and 2 inches above the bottom of the ditch. The grafts are then planted with the dibble, being put down to such a depth that the top bud comes exactly even with the taut line. Two of the best forms of nursery dibbles are shown in Fig. 18. The first, a, consists of a piece of round %-inch iron, IS inches long, furnished with a wooden handle at one end and a curved double point with a V-shaped cleft at the other. The bottom node of the stock is caught in the cleft and the graft forced down to the desired depth. Unless the ground is very light the other form of dibble is preferable. The other dibble, b, consists of a sword-shaped piece of iron 18 to 20 inches long and 2 inches wide, furnished also with a handle. The usual way of using it is to press it into the ground to the desired depth, open the hole a little with a lateral thrust, withdraw it and insert the graft. The dibble is then pushed into the ground again at about an inch to one side of the graft and by another lateral thrust the earth is pressed tightly around the graft. This takes more time than is necessary with the other form of dibble, and unless done carefully there is danger of failing to make the soil close around 120 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. the base of the stock, which is thus left surrounded by an air space. Grafts left in this way are apt to become moldy and fail to make good roots. Both these objections are overcome by using the dibble as shown in Fig. 19. When used in this way the dibble is pushed into the ground only once for each graft and there is no possibility of the j a FIG. 18. Dibbles for planting grafts. graft being suspended without soil in contact with the base. Two men work together, one placing the grafts and the other manipulating the dibble. Where it is necessary to plant in compact soil or in soil containing pebbles a dibble can not be used. In this case it is necessary to dig a trench. The trench should be dug with one side slightly slanting. The grafts are laid against this side and well-pulverized soil shoveled in. If the soil is at all stiff or clayey a couple of inches of sand should RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 121 be placed on the side of the bottom of the trench where the bottom of the stock rests. This will very much facilitate the rooting. (See Fig. 20.) When the grafts are planted they should be completely covered, and very carefully, with 1 or 2 inches of soil. This will leave the \ D ' I 1 FIG. 19. ILLUSTRATING METHOD OF PLANTING WITH DIBBLE. D. Position of dibble when pressing the soil against graft 7 and opening a hole for graft 8. DI. Position of dibble when preparing to press soil against graft 8. S. Loose soil, which falls to bottom of hole and makes it possible to place the graft at exactly the right depth. nursery in ridges, with the unions of the grafts in the center of the ridges and at the original level of the soil. The depressions between the ridges will be about 2 inches lower than the unions. This is advisable, as it makes it possible to irrigate the grafts without injur- FIG. 20. Method of planting grafts in trenches. ing the union by too much water. The ridges should be wide. If too narrow and steep they dry out too easily and the unions will suffer. Cultivation. By the end of April all the grafts should be planted and a good irrigation soon after this is advisable. This should be done in such a way that the ground at the base of the stock will be well wetted. This will start the formation of roots. The ridges 322 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. should not be submerged, but they should be wetted sufficiently to prevent any danger of the drying out of the scions. This is accom- plished by lateral seepage, if the water is run slowly along the hollows between the ridges. A cultivator should be run between the rows as soon as possible after the irrigation, but the ridges should not be disturbed, if it is possible to avoid it, until the scions start. If the soil has a tendency to form a crust, however, it will be necessary to break this crust after any rain that may occur at this time. This is one of the most fruitful causes of failure. If the crust is not broken the buds will have difficulty in pushing their way through and the hard soil will dry down rapidly and many scions be killed. The breaking of the crust must be done with great care, ;* - : - * f FIG. 21. Irrigating the nursery. or the scions will be disturbed and make poor unions. If 2 inches of soil have been placed over the scions a careful man can go over the ridges with a short-toothed rake without injuring any grafts. This should be done as soon as the soil is dry enough not to form clods and before a crust has formed. It is better in this way to prevent the formation of a crust than to break it up after it has formed. This requires very prompt and rapid action, for in some soils a crust forms in less than twenty-four hours after a rain. Until about the first or middle of July there is nothing to do to the nursery but to keep the weeds down, and to see that the scions do not become dry before they are supplied with water by the new roots. The shoots from the scions should begin to appear above the ground in one to two weeks after planting. These shoots are at first yellowish RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 123 and are growing at the expense of the food material stored up in the scion. As soon as roots are formed the shoots become a deeper FIG. 22. Effect of failure to remove^scion roots. green and are then obtaining food from the roots and from the air. By this time the unions are well formed, and the scions being supplied with water by their own roots and by those of the stock are in less 124 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. danger of drying out. The sides of the ridges should now be kept loose by hoeing, and the ground between the rows pulverized by frequent cultivation. Removal of Scion Roots. As soon as the roots on the stock have started, the unions should be examined and all roots which have started from the scions should be removed. This will be about the beginning of July in the warmer districts, and about the end of that month in the cooler. The exact time is determined by digging up a few grafts in various parts of the nursery and examining the bases of the stocks. If all have formed roots it is time to take off the scion roots. The scion roots are useful to the graft in keeping the scion alive and perfecting the union before the stock roots start, and they should, therefore, not be removed too soon. The roots on the stock start later because they are deeper in the soil, where the temperature is lower. If the scion roots are allowed to grow too long, however, they take the nourishment elaborated by the scion leaves and the stock roots are starved. (See Fig. 22.) In this way we may get a large growth of leaves on the scion and a small growth of roots on the stock. If we remove the scion roots too late, therefore, the stock roots may be insufficient to supply the large growth of leaves with the water they need, and the graft will die. It is well, whenever particularly large roots are cut off the scion, to cut back the shoot and to remove some of the leaves. This diminishes evaporation and delays the growth of the scion until the stock has developed sufficient roots to supply it with the necessary water. Removal of Raffia and Suckers. At the same time that the scion roots are removed, the tying material, raffia or string, should be cut on all the grafts where it has not rotted. On the late grafts planted directly in the nursery without previous callusing the raffia will not require cutting if it has been used without bluestoning. The raffia or other tying material should be entirely removed or the grafts will be strangled. (See Fig. 23, 6.) If the stocks have been properly disbudded before grafting they will produce very few suckers. Those which do grow should be removed as soon as they show above the ground, and any that are found when the scion roots are attended to should be carefully cut off. To perform these various operations it is necessary to dig down beside the grafts to below the union. After they are finished the soil should be replaced, but the ridges are not made quite so high as before. The unions should be covered up and any shoots which are very white should be protected by drawing the soil up around RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 125 them. This lowering of the ridges is useful in gradually hardening the unions. The soil is allowed 'to become dry around the unions and they are thus prepared for the complete removal of the soil around the unions which should take place later at a subsequent hoeing. Digging the Grafts. The grafts may be removed from the nursery at any time after the leaves have turned yellow and before they are needed for planting in the spring. It is best, however, to wait until the leaves have fallen and the vines are perfectly dormant. If dug a b c FIG. 23. Effect of failure to remove raffia. at this time and kept in a cool place the buds will not start as soon as if they are left in the ground. The grafts should be dug carefully in order not to injure the top, body, or union. Cutting the roots does no harm, but tearing them off should be avoided. They can be removed satisfactorily with a nursery plant-digger. Sorting the Grafts. As soon as the grafts are out of the ground they should be carefully sorted into three lots in accordance with their root and top growth, and especially with regard to the strength and completeness of the union. These lots are called No. 1 grafts, No. 2 grafts, and culls. The No. 1 grafts are those suitable for planting in the vineyard ; the No. 2 grafts may be replaced in the nursery, and the culls are rejected altogether. 126 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. A No. 1 graft should have a top growth of well-ripened wood at least 10 inches long and well-developed roots at the bottom of the stock. It should have no large scion roots or scars where they have been removed. It should not show injuries due to digging, and there should not be a great difference of diameter between the stock and scion. The most important point is the condition of the union. The stock and scion should be united firmly on both sides and the union should be the strongest part of the vine. A No. 1 graft if bent sufficiently will break either above or below, but not at the union. (See Fig. 24.) The allowable difference in size between stock and scion will differ according to the varieties grafted. A Rupestris St. George or Mourvedre X Rupestris 1202 stock should be as large as the scion; a Riparia X Rupestris 3309 or 3306 may be from one fifth to one fourth smaller, while a Riparia gloire may be from one fourth to one third smaller. The lump or swelling which in nearly all cases occurs just above the union should not be too pronounced. When large it is a sign of lack of affinity between stock and scion or of an imperfect union. (See Fig. 23, a, c.) The No. 2 grafts are those which have some of the defects mentioned above, but which may develop into good vines. As there is doubt of this, however, they should not be planted directly in the vineyard, but placed in nursery for another season. The following year a large proportion of them will have overcome their defects and developed into good two-year-old vines. Grafts which have united well on one side or which have complete unions but small growth may be saved in this way, .though it would probably be better for the vineyard to plant nothing but No. 1 one-year-old grafts. Certain defects can not be overcome. Grafts which have made a heavy top growth by means of scion roots and of which the stock is small and starved should be thrown away. (See Fig. 22.) If the union is imperfect on both sides, or if the enlargement above the union is excessive, there is no hope of making good vines of them. (See Fig. 23, a, c.) Pruning. It is best not to prune the grafts until they are planted or afterwards. If the tops have made a very large growth with large laterals they may be pruned partially in order to facilitate making up into bundles and shipping. All shoots may be cut off except the largest, which should be left full length if not more than 18 inches long. When the grafts are tied up in bundles the roots may be shortened to 6 inches. This is best done by placing the bundles on a wooden block and cutting the roots with a sharp broadax. \ FIG. 24. No. 1 rooted bench grafts. 128 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Conservation and Shipping. Rooted vines require much more care than cuttings, as they are more easily damaged. They are especially liable to injury by drying-out. Grafts are even more sensitive. They should be kept in a cool, moist place until they are shipped or planted. A good way is to heel them in under an open shed or on the north side of a building in sand or loam where there is no danger of their getting too wet. If it is necessary to heel them' in out in the open field they should be protected from the sun by placing over them a bed of straw at least 2 feet thick. Nursery Grafting. Certain varieties of stocks, such as Lenoir and some of the Berlandieri and ^Estivalis hybrids which root with difficulty, do not give good results with cutting grafting and must be rooted first, as already described on page 112. If they have made a good stand in the nursery and there are not too many vacant spaces, they may be grafted without removal. This is known as "nursery grafting." Cuttings under % i ncn i n diameter of other varieties may also be rooted in the nursery and grafted the next year without removal. Either the tongue graft or the wire graft may be used. If the vines have made a large growth and are over y 2 i ncn i n diameter it is better to use one of the methods described on page 137. (See Fig. 26.) The tongue graft is difficult to make in the nursery and the tying is particularly troublesome. Good results can be obtained often by omitting the tying, but the scions send out large numbers of roots. The wire method is particularly well suited to nursery grafting, is very easily performed, and gives excellent results. Over 90 per cent of first-class unions should be obtained. The grafting should be done as near the surface of the ground as possible. The soil is first hoed away and carefully cleaned off the vines, leaving them in a little trench 3 or 4 inches deep. They are then cut of? with pruning shears just below the bud of the original cutting which is nearest to the surface. The grafting is then done in the same way as already described for cutting grafts. The same care in cultivation, removal of suckers, scion roots, and tying material is necessary. Grafts made in this way are very large and vigorous and will give good results if handled properly in the vineyard. There are the same objections to them as to any very large plants, however. They are more liable to injury than smaller plants in removal from the nursery, require more care in planting, and are more liable to suffer from the difference of conditions between the nursery and the vineyard. RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 129 II. THE VINEYARD. Preparation of the Land. Whatever the method of grafting adopted, the land where the vineyard is to be planted should receive the same careful preparation. Profitable vineyards have been established in some soils which have received no more preparation than is needed for a crop of wheat. Such cases are, however, exceptional, and even in these cases better and quicker results would have been obtained if the ground had been properly prepared before planting. The need of thorough preparation of the soil is more urgent when we plant resistant vines than when we plant vinifera varieties on their own roots. This is owing both to the greater sensitiveness of resistant roots to unfavorable conditions and to the greater cost of starting a resistant vineyard, which makes the necessity of quick returns more pressing. In South Africa it is usual to obtain a crop eighteen months after planting bench grafts. This crop may amount to five tons per acre, and even more. This precocity is due in great part to the fact that before planting, the soil of the vineyard is hand-trenched to a depth of 30 inches or more. Hand-trenching is, of course, out of the question in California, where labor is expensive. We can, however, approxi- mate these results by deep plowing and subsoiling. Wherever resist- ant vines are planted, 'the soil should be plowed 2 or 3 inches deeper than the depth to which the bottom of the cutting or graft will reach when planted, and subsoiled several inches below this. A plow which will turn the soil over to a depth of 12 inches, followed by a subsoiler stirring the soil 6 inches deeper, will give results during the first three years of the life of the vineyard that will more than repay the cost in crop alone, and the perfect stand and strong healthy vines will insure good crops in later years. It is doubtful whether a vine which is starved and dwarfed during the first three or four years of its life ever gives the best results in crop. If the land is plowed in the way described the roots of the graft when planted will be in contact with top soil, which is the best for root growth, and the graft should make a growth of several canes 3 or 4 feet long and a strong root system the first year. Fertilization. As a rule, no general fertilization of the soil is needed the first year, the deep plowing being sufficient to insure a strong growth. When replanting the site of an old vineyard or planting vines on land which has been occupied by an orchard, some fertilizer to renew the humus of the soil is advisable. A crop of rye or peas plowed-in the year previous to planting is useful for this purpose. A heavy manuring with from 15 to 20 tons of well-rotted stable 130 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. manure is also excellent, when it can be procured. The manure should be spread on the surface and plowed in. If the manure is not well rotted, however, it may do more harm than good, unless applied at least twelve months before the planting. The vines are apt to dry out or become moldy at the base if they are in contact with very strawy manure. In every case, it is advisable to place a little nitrogenous fertilizer below each vine when it is planted. For this purpose ground or steamed bones, tankage, or old stable manure may be used with advantage. Two or three ounces of the first two or half a shovel of the last well dug in and mixed with the soil at the bottom of each planting hole is sufficient. A general fertilization of the land is usually best postponed until the second year. Intercalary Crops. As a rule it is better not to try to raise any crop between the vines unless there is an abundance of water. In most parts of California the young vines need all the moisture avail- able in the soil during summer and, unless summer irrigation can be given, the soil between the vines should be kept clear of crops and weeds. With irrigation it is possible to raise a crop of corn or other hoed crops without injury to the vines during the first year, providing nothing is grown nearer than 3 feet from the vines. After the first year the land should be given exclusively to the vines. Planting. If the ground has been plowed deeply, as already explained, and no fertilizer is to be used, the grafts may be planted with a dibble. This method has several advantages and can be used in all soils which do not contain large stones or coarse gravel. It is not recommended, however, except for sandy and sandy-loam soils. It is rapid and facilitates the perfect alignment of the vines, as well as makes it much easier to attain the very important object of placing the unions at exactly the right height above the surface of the ground. For planting in this way the roots must be pruned very short. The stronger roots must be pruned down to y inch, and the smaller removed altogether. There is probably some loss of strength to the vines by this close root pruning, but it is not very serious. The young rootlets start from the cut end of the root wherever it is cut, and the main advantage of a rooted vine over a cutting is the rapidity with which the rootlets start and grow. However long we leave the roots they are of no use to the vine until they have developed new rootlets. If we leave the roots longer when planting with a dibble they will be turned up when planted, which will result in crooked and improperly placed roots. Fig. 18c shows a convenient form of dibble. It consists of a sword- RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 131 shaped piece of iron about 15 inches long, a handle furnished with a cross-piece, and a foot-rest. In use, it is pressed into the ground by placing the foot on the foot-rest and then by a backward and forward movement of the handle the hole is opened in the soil and the dibble removed. This hole is made from 8 to 10 inches deep, according to the length of the graft. The graft is then inserted to the right depth and the dibble pressed into the ground again about 3 or 4 inches from the graft and a few inches deeper than the first time. Then by a vigorous thrust of the handle the blade of the dibble is caused to press the soil tightly around the graft. An ordinary garden spade FIG. 25. Illustrating method of planting grafts. (Redrawn after Hit-liter.) may be used for the same purpose. It is particularly necessary that the soil should be in intimate contact with the bottom of the graft. Whatever the length of the graft, the union should be 1 or 2 inches above the general level of the ground. On steep hillsides the union should be placed higher 4 inches or more above the surface. Unless this is done the union will soon be covered by the soil thrown down by the sidehill plows, and it will be difficult or impossible to prevent the growth of scion roots. Grafted vines for use on hillsides should be from 2 to 4 inches longer than for level soils. The stocks should not be less than 12 inches long. A 14- or 15-inch stock and a one-bud scion is the best for this purpose. As soon as possible after planting, not later than the next day, the soil should be hoed up around the graft, leaving a broad hill reaching at least 2 or 3 inches above the union. 132 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. If the soil is stony or imperfectly prepared, or if we desire to apply fertilizers, planting with a dibble is impossible. In this case we must dig a hole for each vine. This hole need not be any wider than the spade, but should be at least 4 inches deeper than the bottom of the graft. The method of planting is shown in Fig. 25. As soon as the hole is dug, 3 or 4 inches of top soil, mixed with fertilizer if it is used, is placed at the bottom. The vine is then put in a slanting position so that its base is near the middle of the hole and its top against the marker. More top soil is then thrown in until the hole is about half full. The soil is then pressed with the foot firmly around the roots and bottom half of the stock. The hole is then filled with loose soil and the graft well hilled up several inches above the union. The hill should be very broad, in order to prevent drying out. With this method of planting great care is necessary to avoid getting any of the unions too deep. If the unions are placed below the surface of the soil the scion will send out roots. If these roots are not removed they will grow large and finally take all the nourishment coming from the leaves. This will result in the starvation and death of the resistant root, and in a few years the vine has nothing but vinifera roots and is as susceptible to injury from phylloxera as if it had never been grafted. If the scion roots are removed twice a year for the first two years and once a year until the vines are seven or eight years old this result may be avoided, and if the work is done promptly and thoroughly few scion roots will be formed after this. To do this properly, how- ever, requires a great deal of careful, conscientious work, which it is difficult to have done on a large scale, and which may be avoided by planting the grafts at the right depth. If the unions are placed too high the roots are brought too near the surface and they may dry out before they have time to grow down into the permanently moist soil. As the unions should be well covered with soil to protect them from the sun during the first summer, it is necessary to make very large mounds if the unions are placed very high. In general it is found that the most convenient position for the union is about 2 inches above the surface of the ground. This will bring the bottom of the graft 8 inches below the surface with an ordinary 10-inch stock. This is sufficiently deep for all except very dry and open soils, if the grafts are well hilled up after planting. In planting with a dibble the planter can estimate the height of the union with sufficient exactness by eye, but when planting in a hole, especially if the surface of the ground is rough or uneven, some kind of guide is necessary. For this purpose a stick 3 feet long and 1 inch in diameter may be used. This stick is laid across the hole, and shows RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 133 the true level of the ground and serves as a guide to show the planter where to place the union. In planting with a number of men where a marked rope or wire is used to show the position of each vine while planting, this rope or wire may be used as the guide to show the height f the union, provided one man is employed in watching the rope to see that it remains stretched at exactly the right height above the surface. Pruning. The pruning of the roots before planting has already been discussed. The top is usually pruned by removing all the shoots except the strongest and cutting that back to two good buds. The superfluous shoots should be cut off clean close enough to the base to remove the base bud. The shoot which is left should be cut through the bud above the top one which is left. In France it is considered better to postpone the cutting back of the main shoot until the buds have started after planting, as indicated in Fig. 25. This prevents to some extent the early starting of the bottom buds and the danger of their injury by spring frosts. It also protects the union from injury during the period which elapses between the planting and the commencement of growth. Staking. To obtain the best results, a vineyard of bench grafts should be staked the year it is planted. Bench grafts grow more rapidly than ungrafted vines. This is especially true when deep preparation of the soil has been practised. Moreover, with most varieties the scion will be a little larger than the stock, which makes the vine top heavy and more likely to bend over and lie flat on the ground. To prevent this and to have a well-shaped vine from the beginning, the shoots growing during the first season should be tied up to a stake. If this is done, it will be possible to give each vine a straight, smooth stem and sym- metrical head at the second pruning. It is only in this way that the full benefit can be obtained of the vigorous growth which properly planted grafts make during the first two years. If the vines are allowed to lie on the ground it will take three or four years to give them the proper shape, and much crop is lost by the heavy pruning necessary for this purpose. The size of stake will depend on the style of pruning that is to be adopted and the height at which the vines are to be headed. For ordinary short-pruned vines a stake 3 feet long and 1 or 1^ inches in diameter is quite sufficient. Such a stake can be driven 2 feet into the ground and will support the vine perfectly for five or six years if the head is made at the usual height of about 10 inches, or lower. After this, the vine should be stout enough to stand without a stake. If the 4 BUL. 180. 134 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. vines are to be pruned long or given a high head a 4- to 6-foot stake will be needed and may be put in the first year. As all vines should be pruned short for the first three years, however, it is as well to use small stakes at first and to replace them with longer and heavier stakes when long pruning is commenced. If the vines are to be headed high, 15 to 18 inches, a 4-foot stake will be necessary, and this will have to be a little heavier, 1^ to 1% inches in diameter. Suckering and Rooting. If No. 1 bench grafts from which the stock buds were properly removed before grafting are used, and if they are planted in the way described, there will be very few suckers from the stock, or roots from the scion, produced. Any which do grow, however, must be very carefully and completely removed. The more thoroughly this is done during the first year the less trouble there will be later, and after the third year there should be hardly any suckers and no scion roots produced at all. As the unions are kept covered during the first year a few scion roots will be produced, especially in rich and moist soil. These should be cut off once during the season about midsummer, at about the time of the second hoeing. Any which develop after that may be removed at the winter pruning. No scion roots will be formed in subsequent years if the unions are above the surface and kept uncovered, as they should be. Some stocks such as Rupestris, and especially Rupestris St. George, are very prone to throw out suckers, but careful work during the first three years will overcome this tendency. To do this the suckers should never be allowed to mature. Three or four times during the first year the vineyard should be gone over carefully and every sucker cut off close down to the stock at the place where it starts. If a piece of the base of the sucker is left, especially if the sucker has matured, a lump will form on the stock, from which there will be an inveterate tendency for suckers to form. A little extra work during the first year will prevent the need of a great deal of work in subsequent years. For the first three or four years the collar of the vine should be cleaned off down 4 or 5 inches below the surface every winter or spring by plowing and hoeing away from the vine. This will expose any suckers which have been overlooked during the summer. All such suckers should be cut out very close, care being taken to remove the slight enlargement at the base of each from which new suckers would start in the following summer. Cultivation. The cultivation of a grafted vineyard does not differ in any way from that of an ordinary vineyard of vinifera varieties. Deep plowing and thorough summer cultivation are equally necessary RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 135 and, owing to the tendency of many grafted vines to heavy bearing, fertilization is more likely to be needed. As a rule, the same methods of pruning are applicable. With very vigorous stocks, such as Rupestris St. George, it may be necessary to prune some varieties longer to counteract a tendency to "go to wood." With most stocks, on the other hand, the fertility of the vines is increased and shorter pruning is advisable. In any case the amount of pruning can be determined by the strength of the vine itself as with ungrafted vines. III. FIELD GRAFTING. It is possible to start a resistant vineyard by planting the stocks directly in the field and grafting them there after they are rooted instead of planting bench grafts. This was formerly the commonest method and is still largely practised in some districts. It is, however, in all cases less satisfactory and more expensive than the methods already described. In some cases on steep hillsides, in very stony or stiff soil it is almost impossible to make a satisfactor}^ vineyard by field grafting. Good results are sometimes obtained by this method in fairly level, loose soils, but the results are so much at the mercy of the weather that even with the best work it is only by chance that good paying vineyards are established in this way. Even when, by an extraordinary combination of favorable conditions, a field-grafted vineyard is successfully established the cost is always more than the cost of a similar vineyard started with bench grafts. As field grafting is still practised to a considerable extent, and as many vineyards of resistant stocks have been planted, it seems necessary to describe the method. Preparation of the Soil. Thorough plowing and subsoiling are even more necessarj^ when planting ungrafted resistants than when planting bench grafts. This is because good results can be obtained only if the resistants are grafted young, and this makes it essential to obtain a good growth the first year. If the stock remains in the ground for two, three, or more years before grafting, it becomes hard and refractory to graft- ing and good unions can not be obtained. The stocks should make sufficient growth the first year to allow of their being grafted the spring following the planting. Cuttings or Hoots. It is better, whenever possible, to plant good cuttings than roots. This is because when they are grafted the follow- ing year the wood where the union is made is a year younger than in the case of roots and the unions are correspondingly more perfect. This is especially true with Rupestris and Riparia stocks, which make 136 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION. unreliable unions when old. With vinifera hybrids, such as Aramon X Rupestris No. 2 and Mourvedre X Rupestris 1202, the age of the stock is not so important. The cuttings should be very carefully selected and only firm, healthy, well-ripened wood used. They should be sufficiently long to allow 4 inches of the top to be left above the surface of the ground. This is very necessary in order to make it possible to graft above the surface, for the graft must be made on the part of the vine corresponding to the original cutting. To graft in the new wood which has grown after planting makes it necessary to wait two or three years, as the first year's growth is usually too thin. Vines grafted in this way, moreover, give very much more trouble by their inveterate habit of throwing out suckers. For these reasons small, thin cuttings or the tips of canes should not be planted in the field. Such cuttings, if well ripened, may be planted in the nursery, where they will make a good growth the first year, and where they may be nursery grafted. The cuttings of some resistant stocks, such as Aramon X Rupestris No. 2, root with difficulty, and if planted directly in the field would require much replanting. With these varieties it is better to plant roots. With all varieties it is better to plant roots in soils where cuttings strike with difficulty. An incomplete stand the first year is difficult to overcome, and increases the expense by spreading the work of planting, grafting, and regrafting over several years. At every stage of the process of starting a vineyard by field grafting some vines may be lost or spoiled, and it is only by the most thorough and careful work that it is possible to avoid the ragged, uneven collection of crippled mon- strosities that too often passes for a resistant vineyard. Age for Grafting. Whenever possible the vines should be grafted the year after planting. Some stocks may make too small a growth of top and root to make a strong graft the first year, and it will be necessary to leave such stocks a year longer. Any stock which is % inch thick and has made a fair top growth should be grafted. It is a great mistake to wait two or three years until the vines are % or 1 inch thick, as is done by many grafters. Methods of Grafting. Wherever possible the vines should be grafted at or above the surface of the ground. In many cases, however, this will be impossible. Some cuttings will have failed to start the top buds and it will be necessary to go below the surface to find a smooth, suitable part of the stock where grafting is possible. The kind of graft to use will depend on the size of the stock. For stocks up to % inch in diameter the methods of tongue and wire grafting already described are the best. For larger vines up to % inch a RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 137 modification of the ordinary tongue graft is the best. Reference to Fig. 26, B, BB, will show how it is modified. If the tongue graft were FIG. 26. Methods of field grafting. A. Whip graft for stocks to of an inch in diameter. B, BB. Whip graft for stocks to J of an inch in diameter. C, CC. Whip graft for stocks over f of an inch in diameter. made in the usual way with stocks of this size it would be necessary to use excessively large scions, which is undesirable, or to have the barks unite only on one side. By cutting the bevel of the stock only part 138 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. way through the vines, as shown in Fig. 26, B, it is possible to make a smaller scion unite on both sides. For still larger vines, those over % inch in diameter, the best graft is the ordinary cleft, shown in Fig. 26, 0, CC. Tying and Waxing. No wax or clay should be used on the graft. Anything which completely excludes the air prevents the knitting of the tissues. A little clay, cloth, or a leaf may be placed over the split in the stock when the cleft graft is used, simply to keep out the soil. Otherwise there is nothing more suitable or more favorable to the formation of a good union that can be put around the graft than loose, moist soil. If the soil is clayey, stiff or lumpy it is necessary to surround the union with loose soil or sand brought from outside the vineyard. It will usually be necessary to tie the grafts. A well-made cleft graft often holds the scion with sufficient force to prevent its displace- ment and no tying is necessary. Wherever there is any danger of the graft moving, however, it should be tied. There is nothing better for this purpose than ordinary raffia. The raffia should not be bluestoned, as it will last long enough without and will be sure to rot in a few weeks and the trouble of cutting it will be avoided. Cotton string or anything which will keep the graft in place for a few weeks may also be used. As soon as the graft is made and tied, a stake should be driven and the union covered with a little earth. The hilling up of the graft may be left for a few hours, except in very hot, dry weather. Finally, the whole graft should be covered with a broad hill of loose soil 2 inches above the top of the scion. Season for Field Grafting. Field grafting should not be commenced as a rule, except in the hottest and driest localities, before the middle of March. Before that there is too much danger that heavy rains may keep the soil soaked for several weeks a condition very unfavorable to the formation of good unions. In any case the grafting should not be done while the soil is wet. Grafting may continue as long as the cuttings can be kept dormant. It is difficult to graft successfully, however, when the bark of the stock becomes loose, as it does soon after the middle of April in most localities. Treatment the First Year. Field grafts require practically the same treatment as bench grafts in the nursery, except that there is little or no danger of their drying out, if they are properly mounded up. There is usually sufficient sap in the stock to keep them moist. They should be disturbed as little as possible for two or three months after grafting. Some time in July it is necessary to remove the suckers RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 139 and scion roots. If the suckers grow rapidly and abundantly it may be necessary to remove some of them before this. They should not be allowed to grow large enough to shade the graft or to render their removal difficult without injury to the scion. It is best not to touch FIG. 27. Old grafted vine on which the scion roots have been allowed to grow. The upper series of roots are all vinifera, only the lower series resistant. This vine was killed by phyl- loxera. the scion roots until the middle or end of July, when they should be removed with the same care exercised in the nursery. As the graft grows it should be tied up to the stake, otherwise it is liable to be broken off or loosened at the union by the wind or the cultivators. Regrafting. Perhaps the most troublesome and unsatisfactory feature of field grafting is the necessity of regrafting a large number of stocks. Though exceptionally as high as 95 per cent of the grafts have been known to grow, the usual number will be between 50 and 75 per cent, and even of these some will be weak, owing to incom- 140 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION. plete unions. It is usual to attempt to regraft all the stocks which fail to grow the first time. This is done the following spring at the same time that the grafting of the vines which were too small the first year is undertaken. The regrafting must be done one joint further down than the first grafting, as the wood will be unhealthy, if not dead, where grafted the previous year. This in most cases will bring the union below the surface, with all the attendant troubles of scion roots. (See Fig. 27.) Unless the suckers have been allowed to grow the previous year FIG. 28. Herbaceous graft. where the grafts failed, the stocks will be weak and will not make good unions. Regrafting very seldom gives a strong healthy vine,, and some even of the advocates of field grafting believe it is best to> dig up all the vines which fail the first year and replace them with bench grafts. Herbaceous Grafting. Vines may be grafted during the summer by using the canes or buds of the current year's growth. Numerous, methods have been described for doing this, but none of them have met with much success in California. A few growers, however, have- successfully budded and grafted Rupestris St. George stocks during the growing season, and their methods may be of use as an adjunct to field grafting and to a smaller extent to bench grafting. RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 141 Instead of regrafting below the ground the second year a stock which has failed, a couple of suckers may be allowed to grow during the summer of the year the grafting is done, and these suckers may be green grafted above ground the same or the following summer. When done successfully the unions are so perfect that the passage of sap from stock to scion is sufficiently free not to force the strong growth of shoots from the stock which occurs when we regraft on new wood in the usual way when the vine is dormant. Figs. 28 and 29 show two forms of herbaceous grafting which have been successfully practised in California. Fig. 29 is simply the- FIG. 29. Herbaceous bud. ordinary T bud used by nurserymen on fruit trees. Fig. 28 is a tongue graft similar to that already described, but made with great care to obtain a perfect fit. For successful green grafting the wood of both stock and scion must be in just the right condition of maturity. If the grafting is done too early the tissues are too soft and brittle, dry out too easily, and few of the grafts grow. If done too late the buds can not be inserted properly and the grafts have not time to make a complete union. The following extracts from a letter kindly written by Mr. Thomas Casalegna, of San Martin, Santa Clara County, gives some very valuable hints regarding the herbaceous budding and grafting of vines : "1. All buds put in from July 15 to August 15 start the same year r 142 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. but may be injured by fall frosts. Those put in from August 15 to September 15 remain dormant until the following year, unless the stock is exceptionally vigorous. "2. Budding is most successful in the month of August. "3. The buds should be taken from canes which have reached the stage of maturity indicated by the pith turning white and just before the bark turns yellow. "4. The buds are inserted on canes of the current year's growth, unless the vines are exceptionally vigorous. "5. Green grafting is most successful in June, provided the scions are hard enough. The pith must be white. Younger scions with green pith have completely failed with me. In a strong- growing vineyard grafting may be done in July. "6. The leaves are taken off the scions when they are cut. If they are to be used immediately they are placed in water; if to be carried some distance they are placed in a wet sack. "7. I tie the buds and grafts with German knitting yarn. "8. I find that green grafting is more successful than budding, if care is taken to get suitable scions in June. ' ' The season for herbaceous grafting will, of course, vary according to the locality. Hot weather immediately following the work is fatal to most of the grafts. Mr. Casalegna states that if two or three cool days follow the insertion of the buds or scions he obtains an almost perfect stand. The use of an elastic tying material such as yarn, as recom- mended, seems essential. If raffia is used the shrinkage of the tissues which follows grafting allows the graft to become loose and to dry out. COMPARISON OF VARIOUS METHODS OF STARTING A RESISTANT VINEYARD. Bench grafting cuttings is unhesitatingly recommended for the following reasons : 1. Both stock and scion are young and of the same size. The unions are, therefore, strong and permanent. 2. The grafting is done under conditions favorable to rapid and effective work. 3. The grafting can be done in any weather, and may extend over three or four months. Bench grafting may be done on rainy days when other work is not pressing or can not be done. 4. The work is more easily supervised. One man who thoroughly understands all details of the grafting can oversee the work of several unskilled workmen, which makes it possible to employ cheaper labor for much of the work. 5. The cultural conditions are more easily controlled. There is much less danger of inferior results due to excessively wet or dry weather RESISTANT VINEYARDS GRAFTING, PLANTING, CULTIVATION. 143 during the growing season. In the nursery the vines can be cultivated, irrigated, and generally attended to much more perfectly than in the field. 6. A rigid .selection of vines for planting can be made, rendering it possible to have nothing in the vineyard but strong plants and perfect unions. 7. As perfect a stand can be obtained in the vineyard the first year in any soil or season as can be obtained when planting the ordinary non- resistant vines. (See figure on cover.) 8. The union of every vine can be placed exactly where we want it. 9. The land where the vineyard is to be planted can be used for other crops for one year longer than when field grafting is adopted. 10. All the cultural operations during the first year are much less expensive, as they are spread over a much smaller area of land. Two acres of nursery will produce enough bench grafts to plant one hundred acres of vineyard. In short, starting a resistant vineyard by means of bench grafts is much better than by any other method used at present, because it is the least costly and gives the best results. This is true whether we produce our own bench grafts or whether we buy them at the present market rate. Growers are earnestly cautioned, however, against planting any bench grafts but the first choice. Second and third choice are little better than field grafts, and many have been offered for sale lately which are sure to give disappointment in the vineyard. There are several nurserymen in the State now who are producing No. 1 bench grafts which are equal, and for planting here perhaps superior, to any produced in Europe. With regard to nursery grafting and bench grafting roots, all that can be said in their favor is that they are fairly good methods when bench grafting cuttings is impracticable. They enable us to produce rooted grafts with stocks which, owing to the difficulty with which they root, are very difficult to bench graft as cuttings. By their means we are enabled to utilize resistant cuttings which are too small to bench graft, and a larger percentage of well-grown grafted vines is obtained from the nursery. On the other hand, as the stock is at least two years old when grafted there is reason to fear that with some stocks many unions will fail as the vines become older. The vines are larger when they are taken from the nursery, which increases the cost of removal, and there is little i,f any gain in growth over bench grafts when planted in the vineyard. Finally, the method requires a year longer and is in every way more expensive. Of field grafting, nothing favorable can be said except that it is more generally understood and the expense and work are spread over several 144 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. years instead of being principally in the first. Many of its disad- vantages may be inferred from what has already been said of the advantages of bench grafting. The principal are the extreme difficulty of obtaining a perfect stand, the trouble with scion roots and stock suckers, the impossibility of detecting imperfect unions until the vines die, and finally the greater ultimate cost. ACKNOWLEDGMENTS. In the preparation of this bulletin I have been greatly assisted by many grape-growers and nurserymen who have kindly allowed me to examine their methods, notably by Messrs. Frank Swett of Martinez, W. G. Doidge of Lodi, George E. Roeding of Fresno, and Thomas Casalegna of Evergreen. STATION PUBLICATIONS AVAILABLE FOR DISTRIBUTION. REPORTS. 1896. Report of the Viticultural Work during the seasons 1887-93, with data regarding the Vintages of 1894-95. 1897. Resistant Vines, their Selection, Adaptation, and Grafting. Appendix to Viticultural Report for 1896. 1898. Partial Report of Work of Agricultural Experiment Station for the years 1895-96 and 1896-97. 1900. Report of the Agricultural Experiment Station for the year 1897-98. 1902. Report of the Agricultural Experiment Station for 1898-1901. 1903. Report of the Agricultural Experiment Station for 1901-1903. 1904. Twenty-second Report of the Agricultural Experiment Station for 1903-1904. BULLETINS. Reprint. Endurance of Drought in Soils of the Arid Region. No. 128. Nature, Value and Utilization of Alkali Lands, and Tolerance of Alkali. (Revised and Reprint, 1905.) 131. The Phylloxera of the Vine. 133. Tolerance of Alkali by Various Cultures. 138. Citrus Fruit Culture. 139. Orange and Lemon Rot. 140. Lands of the Colorado Delta in Salton Basin, and Supplement. 141. Deciduous Fruits at Paso Rohles. 142. Grasshoppers in California. 143. California Peach-Tree Borer. 144. The Peach-Worm. 145. The Red Spider of Citrus Trees. 146. New Methods of Grafting and Budding Vines. 147. Culture Work of the Substations. 148. Resistant Vines and their Hybrids. 149. California Sugar Industry. 150. The Value of Oak Leaves for Forage. 151. Arsenical Insecticides. 152. Fumigation Dosage. 153. Spraying with Distillates. 154. Sulfur Sprays for Red Spider. 155. Directions for Spraying for the Codling-Moth. 156. Fowl Cholera. 158. California Olive Oil; its Manufacture. 159. Contribution to the Study of Fermentation. 160. The Hop Aphis. 161. Tuberculosis in Fowls. (Reprint.) 162. Commercial Fertilizers. (Dec. 1, 1904.) 163. Pear Scab. 164. Poultry Feeding and Proprietary Foods. (Reprint.) 165. Asparagus and Asparagus Rust in California. 166. Spraying for Scale Insects. 167. Manufacture of Dry Wines in Hot Countries. 168. Observations on Some Vine Diseases in Sonoma County. 169. Tolerance of the Sugar Beet for Alkali. 170. Studies in Grasshopper Control. 171. Commercial Fertilizers. (June 30, 1905.) 172. Further Experience in Asparagus Rust Control. 173. Commercial Fertilizers. (December, 1905.) 174. A New Wine-Cooling Machine. 175. Tomato Diseases in California. 176. Sugar Beets in the San Joaquin Valley. 177. A New Method of Making Dry Red Wine. 178. Mosquito Control. 179. Commercial Fertilizers. (June, 1906.) CIRCULARS. No 1. Texas Fever. No. 16. Notes on Seed-Wheat. 2. Blackleg. 17. Why Agriculture Should be 3. Hog Cholera. Taught in the Public Schools. 4 Anthrax. 18. Caterpillars on Oaks. 5. Contagious Abortion in Cows. ' 19. Disinfection of Stables. 7. Remedies for Insects. 20. Reading Course in Irrigation. 9. Asparagus Rust. 21. The Advancement of Agri- 10. Reading Course in Economic cultural Education. Entomology. (Revision.) 22. Defecation of Must for White 11. Fumigation Practice. Wine. 12. Silk Culture. 23. Pure Yeast in Wineries. 13. The Culture of the Sugar Beet. 15. Recent Problems in Agriculture. What a University Farm is For. UNIVERSITY OF CALIFOBNIA PUBLICATIONS. COLLEGE OF AGRICULTURE, AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA. OR POWDERY MILDEW OF THE VINE By FREDERIC T. BIOLETTI EFFECT OF OIDIUM ON YOUNG GROWTH. BULLETIN NO. 186 (February, 1907) BERKELEY THE UNIVERSITY PRESS BENJAMIN IDE WHEELER, Ph.D., LL.D., President of the University. EXPEEIMENT STATION STAFF. E. J. WICKSON, M.A., Acting Director and Horticulturist. E. W. HILGARD, Ph.D., LL.D., Chemist. W. A. SETCHELL, Ph.D., Botanist. ELWOOD MEAD, M.S., C.E., Irrigation Engineer. C. W. WOODWORTH, M.S., Entomologist. R. H. LOUGHRIDGE, Ph.D., Agricultural Geologist and Soil Physicist. (Soils and Alkali.) M. E. JAFFA, M.S., Nutrition Expert, in charge of the Poultry Station. G. W. SHAW, M.A., Ph.D., Agricultural Technologist, in charge of Cereal Stations. GEORGE E. COLBY, M.S., Chemist. (Fruits, Waters, Insecticides.) (Absent on leave.) RALPH E. SMITH, B.S., Plant Pathologist and Superintendent of Southern Cali- fornia Pathological Laboratory and Experiment Stations. A. R. WARD, B.S.A., D.V.M., Veterinarian and Bacteriologist. E. W. MAJOR, B.Agr., Animal Industry. F. T. BIOLETTI, M.S., Viticulturist. (Grapes, W T ine, and Zymology.) H. M. HALL, M.S., Assistant Botanist. H. J. QUAYLE, A.B., Assistant Entomologist. JOHN S. BURD, B.S., Chemist in charge of Fertilizer Control. C. M. HARING, D.Y.M., Assistant Veterinarian and Bacteriologist. E. H. SMITH, M.S., Assistant Plant Pathologist. H. J. RAMSEY, M.S., Assistant Plant Pathologist. T. F. HUNT, B.S., Assistant Plant Pathologist. R. E. MAN SELL, Assistant in Horticulture, in charge of Central Station Grounds. G. R. STEWART, B.S., Assistant in Station Chemical Laboratory. , Assistant in Soil Laboratory. RALPH BENTON, B.S., Assistant in Entomology. LUDWIG ROSENSTEIN, Laboratory Assistant in Fertilizer Control. ALFRED TOURNIER, Assistant in Viticulture. HANS HOLM, Student Assistant in Zymology. A. J. GAUMNITZ, Assistant in Cereal Laboratory. J. C. BRADLEY, A.B., Assistant in Entomology. D. L. BUNNELL, Clerk to the Director. ' JOHN TUOHY, Patron ) J. T. BEARSS, Foreman } Tulare Sub-Station, Tulare. J. W. MILLS, Horticultural Assistant in Southern California, Riverside. J. W. ROPER, Patron ) E. C. MILLER, In charge } Universi tj Forestry Station, Chico. ROY JONES, Patron ) N. D. INGHAM, Foreman } Univer sity Forestry Station, Santa Monica. VINCENT J. HUNTLEY, Foreman of California Poultry Experiment Station, Peta- luma. The Station publications (REPORTS AND BULLETINS), so long as available, ivill be sent to any citizen of the State on application. OIDIUM OR POWDERY MILDEW OF THE VINE. Fungous Diseases of the Vine. California is peculiarly fortunate in its freedom from most of the serious fungous vine diseases which add so much to the expense and uncertainty of grape growing in most countries. Peronospora, Black Rot, and Anthracnose are here quite unknown. Of the four most serious fungous diseases which attack the above-ground portions of the vine, these three are the most to be feared, as they are not only capable, if neglected, of destroying the whole crop of a vineyard, but require the utmost vigilance and much troublesome treatment with winter washes and summer sprays to hold them in check. Their absence makes quite unnecessary the swabbing of the dormant vines with sulfate of iron and the spraying of the growing vines with Bordeaux mixture which are adopted here by some vine- yardists who have learned the practice in Europe or the Eastern States where it is necessary. On the other hand, the remaining serious fungous disease Oidium exists in all parts of California. From one point of view, this is the most serious disease of the four, as, if uncontrolled, it is capable of spreading more universally through the vineyards and of absolutely destroying the crops in nearly all. From another point of view, it is the least to be feared, as it is possible to control it completely, at least fti most parts of California, by much simpler and less expensive meth- ods than are needed for the others mentioned. Introduction of Oidium into Europe. With the exception of An- thracnose, which is a native of Europe, all these diseases originated on the wild vines of the Eastern and Central parts of the United States. Peronospora and Black Rot are comparatively recent introductions into Europe. The* former was observed for the first time in 1878, the latter not until 1885. The Oidium was first noted in Europe about 1845, when an English gardener named Tucker found it in graperies at Margate, near the mouth of the Thames. It was discovered two years later in the hot-houses of Paris and Belgium. Severity of the Disease in Europe. From this time it spread rap- idly, until by 1851 it had reached every grape-growing country of Europe. The amount of injury done by the disease was enormous and increased every year, reaching its maximum in France about 1854. In 316 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. this year it reduced the crop of grapes in France over 75 per cent., in many districts totally destroying the crop. Discovery of the Utility of Sulfur. After 1854, the grape growers of France commenced to learn how to control the disease. The use of sulfur for this purpose, discovered and perfected between 1850 and 1853, soon became general, and by 1859 the crop of grapes had reached its normal volume in France. The effect of Oidium in diminishing the crop and the effect of sulfur in controlling the disease in one depart- ment of France is well shown by fig. 1. This figure, which is adapted from one published in the nursery catalogue of F. Richter, Montpellier, indicates also the destruction of French vineyards by Phylloxera and their rehabilitation by means of resistant vines. The rapidity with which sulfur enabled the French grape growers to reestablish their vineyards is in contrast with the slow r er process of controlling the phyl- loxera. In three or four years after the use of sulfur became general in the Herault the crops had reached their normal volume. It has taken twenty years to reestablish the same vineyards on phylloxera resistant stocks. OIDIUM / X PHYLLOXERA SULFUR VINES RESISTANT Fig. 1. Showing (1) the reduction of crop of wine in the Herault from 3,900,000 hectoliters in 1850 to 1,000,000 hectoliters in 1856 by the attack of Oidium; (2) the rapid increase of crop after the general use of sulfur; (3) the re- duction by phylloxera of the crop from 15,200,000 hectos in 1869 to 2,100,- 000 hectos in 1885; and (4) the gradual increase due to the use of resistant vines. Damage done by the Disease in California. In California the Oidium has never produced such wide-spread and serious injury as that indicated above. This arises principally from the dryness and heat of the atmosphere during summer in most of our grape-growing regions. The dryness of our climate is undoubtedly the cause of our OIDIUM OR POWDERY MILDEW OF THE VINE. 317 immunity to Peronospora, Anthracnose, and Black Rot, and while Oidium requires less moisture than these diseases for its development, it spreads more rapidly and is more difficult to control in a moist at- mosphere than in a dry one. At the same time, the Oidium does far more harm, even in Cali- fornia, than is usually suspected, and in certain regions and certain seasons may totally destroy the crop and diminish the crops of follow- ing years by injuring the vine. There has been a recrudescence of the intensity of this disease both in Europe and California during the last few years. This is due in all probability not to any change in the fungus or of the seasons, as has been suggested, but to the neglect of regular sulfuring by the grape growers, who have become careless after years of comparative immu- nity due to more or less general treatment for the disease. While most grape growers in California sulfur their vines in some way, many of them do not succeed in completely controlling the disease and are often doubtful of the utility of the treatment. Where good sulfur does not give immunity it is because it has not been applied in the right way or at the right time. Many growers who do succeed in keeping their vines free from Oidium do so at the expense of far more sulfur and labor than are necessary. The main object of this bulletin, therefore, is to point out the meth- ods of control which have been generally found the best and least costly. DESCEIPTION OF THE DISEASE. Relationships of tJie Disease. This disease, usually called Mildew in California, is caused by a fungus belonging to the same group as the fungi which cause the mildews of roses, hops, beans, and apples and is generally referred to as Oidium in Europe. The disease known as Mildew or Peronospora in Europe and the East is totally different and caused by a fungus of very different character. In order to distinguish the two, the Oidium is sometimes called Powdery Mildew and the Peronospora, Downy Mildew. As only one exists in California, the use of the word Mildew should lead to no confusion, though perhaps it is best to adopt Oidium as the name of this disease. Symptoms and Effect on the Vine. The Oidium attacks all her- baceous parts of the vine, leaves, canes, flowers, and fruit. In the spring, the young leaves which are attacked show at first whitish patches about one-quarter of an inch in diameter on the upper or lower surfaces. (See fig. 2.) 318 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. As the disease progresses these patches run together until a large part of the surface of the leaf may be covered with a grayish white mildew. The leaf ceases to grow and curls up towards its upper sur- face. (See figure on cover.) Fig. 2. White patches of Oidium on upper surface of young leaf. As the shoots lengthen, the canes may be attacked in the same way. The patches of mildew appear usually near the bases of the canes and are difficult to see until they acquire the gray tint. In severe cases, the fungus may completely cover the whole surface of the cane, but it is usually confined to patches. If these patches are rubbed the fungus comes off completely. The places where it has been, however, will turn dark later owing to injuries to the superficial cells of the bark. (See % 3.) Fig. 3. Blackening of canes due to Oidium. OIDIUM OR POWDERY MILDEW OF THE VINE. 319 These marks, at first brown, later black, are usually branching or fern-like in form, showing the points of attack of the fungus. If the canes are attacked when young, they fail to mature properly and often turn black over their whole surface. It is this form of Oidium which has sometimes been mistaken for Anthracnose in California. Later, the blossoms and fruit may be attacked. When the blossoms are attacked they fail to set, and if the berries are attacked when very small, they will fail to develop and will drop off. If the fruit reaches nearly full size before being affected, it continues to develop, but irreg- ularly. The parts of the epidermis injured by the fungus become hard- ened and cease to grow. This results in irregularity in the form of the berry and in severe cases in cracking. (See fig. 4.) Fig. 4. Berries badly affected and cracked. (After Foex.) If this cracking occurs early, the grapes dry up completely before ripening. If later, they may develop sugar and can be used for wine making, but the crop is diminished in volume. In moist seasons the berries which are cracked usually become the prey of blue mould and are completely destroyed. After the grapes have lost the green color due to the presence of chlorophyll in the skin and have commenced to ripen they are not at- tacked by Oidium. The markings and blotches which are often seen on ripe grapes are due to injuries .to the skin caused by the presence of the fungus on the grapes before they ripened. If the attack has not been early or serious enough to prevent the grapes reaching normal 320 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. size they may still make good wine. The markings, however, are very objectionable on table and raisin grapes and decrease their value. Tokay and Muscat grapes often show the dark, fern-like markings characteristic of the disease similar to those shown on the canes. ( See fig. 3.) When abundant, these markings, which are accompanied by a thickening of the skin, injure the appearance of the raisins. Where the skin of the Muscat grape has been attacked by Oidium it will re- main smooth after drying and not show the fine wrinkling character- istic of the finest raisins. A vine of which the leaves are badly attacked has a peculiar color and wilted appearance. (See figure on cover.) This appearance is only shown when the conditions of temperature and moisture are favor- able to the growth of the fungus on the exterior leaves. This can occur only at the beginning of the season in the warmer and drier parts of the State. When the air is hot and dry the fungus cannot grow on the outer leaves. The proper favorable conditions, however, may still exist in the interior of the vine. For this reason vines may look perfectly healthy from a little distance, while the fruit and the bases of the canes may be covered with Oidium. A vine which is badly attacked has a moldy smell readily perceptible to many people. DESCRIPTION OF THE FUNGUS. Mode of Attack. The botanical name of the fungus is Uncinula spiralis (Berkeley and Cooke), and it belongs to the family or group of Erysipheae. All the members of this family are parasites which live upon the outer surfaces of leaves and other green organs of plants. The white "mildew" which they form on these surfaces consists of the branching threads or mycelium, which constitute the vegetative body of the fungus. This mycelium grows only on the surface, unlike the mycelia of Peronospora and other parasitic fungi which enter the tis- sues of the host plant. It obtains its nourishment from the epidermal cells of the plant attacked, by means of suckers haustoria which penetrate these outer cells. The outer cells thus attacked become dark colored. The fact that the Oidium does not penetrate the tissues of the vine much facilitates its control and renders its destruction possible at any stage without injury to the host plant from the remedies applied. Summer Form of the Fungus. The mycelial threads of the Unci- nula spiralis are extremely fine not over two ten-thousandths of an inch in diameter. They elongate a f nd grow over the surface to which they are attached by their haustoria and at intervals send out upright branches hyphae thirty to forty ten-thousands of an inch long. OIDIUM OB POWDERY MILDEW OF THE VINE. 321 Fig. 5. Various forms of Uncinula spiralis. I, II. Perithecia showing /, appendages, and a, asci. III. Summer form showing m, mycelium; t, hyphae; c, conidia; and h, haustoria. IV. Group of asci removed from perithecium emitting s, ascospores. (Ill and IV, after Viala.) V. Summer form of Oidium as it appears on surface of leaf. VI. Ditto showing effect of sulfur (d). (V and VI, after Mares.) 322 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. These hyphae are somewhat thicker than the mycelial threads, grad- ually increasing in diameter from the bottom to the top until they become two or three times as thick as the threads from which they arise. Cross partitions divide the hyphae into several cells, the upper- most of which finally becomes detached and forms a conidium or summer spore. The hypha continues to grow and tne second cell de- velops into another conidium. This process continues as long as the conditions are favorable throughout the summer, each hypha produc- ing a large number of conidia. These conidia are egg-shaped and measure about 5 X 12 ten-thousandths of an inch. "When a conidium falls on a suitable part of the vine it sends out a germinating tube which fixes itself by haustoria and grows into a new mycelium which in turn produces more summer spores. (See fig. 5, IIIc.) In this way, all the green parts of a whole vine may finally be covered Avith a coating of mycellium, hyphae, and conidia, which to- gether form the whitish or grayish matter we know as "Mildew" or Oidium. Winter or Resting Forms. In the autumn another form of the fungus is often produced. Among the felted threads of the mycelium may be seen with the unaided eye numerous round black bodies, which are perithecia, or receptacles containing the spores. These bodies have an average diameter of about % 50 of an inch, which is about one-third the diameter of the dot of an i in the print of this bulletin. (See fig. 6,,A,B.) Under the microscope they are seen to vary in color from yellow when unripe to nearly black when mature. (.See fig. 7.) ' "* A. x> Fig. 6. Photomicrographs of Perithecia on Surface of Leaf. A. Magnified 8 times. B. Magnified 35 times. OIDIUM OR POWDERY MILDEW OF THE VINE. 323 A mature perithecium consists of a nearly spherical case containing from four to eight cell-sacks called asci. The walls of this case are strong and resistant to cold and other unfavorable conditions which destroy the summer forms of the fungus. They are made up of thick polygonal cells and form a very efficient protection to the asci. An ascus contains from four to six spores. (See figs. 8 and 5, IV.) Each penthecium is furnished with 10 to 25 hair-like appendages of about the same thickness as the mycelial threads and from one-one hundredths to one-fiftieth of an inch in length. These appendages are divided by several cross partitions and are coiled at the free end. They consist usually of a single thread, but occasionally branch. (See fig. 5, II.) The perithecia remain upon the canes^ and leaves or in the soil until the return of warm weather in spring. As soon as the temperature becomes sufficiently high, the walls of the perithecia .break open and allow the asci to emit their spores. These spores, when they reach a leaf or growing shoot, germinate in the same manner as the summer spores and give rise to a new generation of Oidium. The perithecia do not all emit their spores at the same time owing to the different conditions of the places in which they have passed the winter. Some may even remain in the soil until the following spring. Perithecia have been shown to contain spores capable of germination eighteen months after their formation. 1 It is therefore impossible to completely exterminate the fungus in a vineyard in one year, however thorough the treatment. Burying the perithecia by plowing-in simply aids in their preservation and they are ready to cause a new infection two years later when brought to the surface again by later plowing. Although the Oidium was introduced into Europe as early as 1845, it was not until 1892 that the winter form of the fungus was found there. It was for this reason uncertain until that time that our Oidium and that of Europe were identical. It seems probable that the fungus, under some conditions, carl pass the winter in the conidial or summer form. At all events, in certain districts the perithecia have never been found and are therefore absent or very rare. They are very rare in the interior valleys of California. On the other hand, they are produced in immense numbers on vines within the influence of the summer ocean fogs. At Berkeley it is com- mon to find thousands of them on every leaf and cane of a vine. More than 100,000 perithecia have been counted on the upper surface of a 1 Revue de Viticulture, No. 655, p. 324 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. **Hr* * -^ Fig. 7. Photomicrograph of Perithecia taken from Vine Leaf; magnified 30 times. The light colored bodies are immature perithecia; the dark colored, mature peritliecia which have been burst open by pressure. Fig. 8. Photomicrograph of Perithecia magnified about 200 times. One perithe- cium has been broken by pressure and the asci are partially pressed out. The winter spores can be seen through the transparent walls of the asci. OIDIUM OR POWDERY MILDEW OF THE VINE. 325 single leaf, and as each perithecium contains fifty or more spores, the number produced on a single vine may be hundreds of millions. In Europe they are formed in September and October. In Berke- ley they are found in abundance as early as the middle of June. Their formation seems to depend on weather conditions. If after a period of warm, moist weather, which has produced an abundant growth of mycelium, the temperature suddenly falls to near the lowest limit for the growth of the fungus (50 P.), they are produced rapidly and in great numbers. These are weather conditions which often occur at Berkeley and in the valleys nearest the coast. In the interior very different conditions exist. The fungus may grow abundantly during the spring and early summer, but there is seldom any fall of temperature at this season sufficient to cause the production of the winter spores. As the summer advances, the air be- comes too hot and dry for the fungus, so that by the time the cooler weather of October arrives, most of the Oidium has disappeared and the abundant growth of strong mycelium .which is necessary does not exist. CONDITIONS FAVORING THE DISEASE. Variations in Susceptibility of Varieties. There is considerable difference in the susceptibility of various varieties of vines and there- fore in the ease with which they can be kept free from the disease. All species of American vines, Labrusca, Riparia, Rupestris, etc., are much less severely attacked than the European varieties of Vitis vinifera. Among the latter there exist, however, various degrees of suscepti- bility. Of the varieties cultivated in California, those most easily and severely attacked are the Carignane, Flame Tokay, Muscat of Alex- andria, Gutedel, Cabernet, Riesling, Clairette, Folle blanche, Ugni- blanc, and Petite Sirah. Tlie more resistant are the Beclan, Duriff, Malbec, Mataro, Grenache, Alicante Bouschet, Petit Bc/tischet, Ara- mon, Mourastel, Vernaccia, and Marsanne. All varieties, however, are capable of being severely injured if the weather conditions favor the growth of the fungus. The Beclan and Duriff are perhaps the most resistant of all mentioned and are for this reason very valuable vari- eties to plant in localities within the influence of the summer ocean fogs. Temperature and Moisture Conditions. The fungus requires cer- tain degrees of temperature and moisture for its development. It grows most vigorously and abundantly in sheltered shady positions. 326 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. For this reason, vines on walls or trellises are more liable to attack, while vines out in the open vineyard, especially where they are sub- jected to the full action of the wind, are less severely affected. Though the fungus requires less moisture than most others causing diseases of the vine, it will not grow in an atmosphere that is too dry. In the drier regions of California it is much less frequent than along the coast. Vines in low places or near the banks of rivers or irrigation canals are often attacked when the rest of the vineyard is free. Rains or fogs in the spring or early summer are very favorable to the growth of Oidium, especially if they are accompanied by a warm temperature. The fungus will grow at a wide range of temperature. Below 50 F., however, its growth is arrested and for 15 or 20 degrees above this its growth is slow. Above 75 F., its growth is rapid and reaches its maximum at about 90 F. or 95 F., providing the air remains suffi- ciently moist. At about 100 F. it ceases to grow and at few degrees above this it is killed. These considerations explain the different ways in which the fungus attacks vines in different localities and in different seasons. In the coast regions, during the spring, the Oidium attacks most severely the outer leaves and the ends of shoots on the south and east sides of the vine. The parts of the vine which are shaded do not be- come sufficiently warm for the growth of the fungus. As the season progresses and the temperature of the air rises, the west and north sides of the vine become affected and finally, by midsummer, the fun- gus is able to grow on all parts of the vine and the bunches and bases of the canes are attacked. Very near the coast all parts of the vine are liable to attack throughout the summer, but in the main coast valleys, the fungus is usually confined to the interior of the vine after the middle or end of June. In the interior valleys, it is very unusual to find the outer leaves of the vines attacked at any season. Vines which are much shaded by neighboring trees or buildings, however, may be attacked in the late spring in a way similar to that which occurs nearer the coast. Usually the fungus is first seen at or just before blossoming time and its attacks are confined to the canes, flower bunches, and interior leaves. This early attack sometimes causes a great loss of crop even when to a cur- sory examination the vine appears perfectly healthy. During the summer, the dry air and great heat prevent the devel- opment of the fungus, and in fact destroy the greater part of it. The crop, however, may be seriously injured before sufficiently hot weather arrives. Most varieties of grapes in the hotter parts of the Sacra- OIDIUM OR POWDERY MILDEW OF THE VINE. 327 mento and San Joaquin valley will ripen their fruit perfectly if they escape the spring infection. Late ripening varieties, however, such as some of the table grapes, may be attacked during the cooler weather of autumn and in some seasons any variety growing vigorously in moist places may be attacked during summer and autumn. CULTUEAL METHODS OF CONTEOL. The Oidium can be checked to some slight extent by cultural meth- ods. Anything which permits the sun and air to get to all parts of the vine more completely will lessen the danger from mildew. Rows of trees which shade the vines on the south side can often be removed with advantage. Vines planted wide apart are less subject to the dis- ease, as they dry off more quickly in the morning. For the same reason, the rows of trellised vines should run north and south in order to facil- itate the drying action of the rising sun. Low trellised vines' are often less subject to Oidium than ordinary vines, as the foliage is spread over a larger surface and not massed around the head as in vase prun- ing. On the other hand, high trellised vines are usually more subject, as the wind and sun do not penetrate them so well. Drainage of the wet places in a vineyard and methods of pruning and training which spread the vine out so that no part is surrounded by still moist air will tend to diminish the intensity of the disease. SULFUE TEEATMENT. Mode of Action. No cultural method is capable of completely pro- tecting the vines from Oidium except under the most favorable condi- tions and with the most resistant varieties. Some special treatment, therefore, is nearly always necessary. Of all the methods tried, there is none so effective as the dusting of powdered sulfur over the vines. Sulfur acts by means of the fumes it gives off when the tempera- ture is sufficiently high. These fumes destroy the mycelium and summer spores of the fungus, and if present in sufficient abundance will destroy every vestige of Oidium in the vineyard with the exception of the perithecia. The exact nature of the fumes given off is uncertain. Some authors believe them to consist of sulfurous acid gas identical with that pro- duced by the burning of sulfur and to be due to slow oxidation. The odor perceptible on a hot day in a sulfured vineyard, however, has not the pungent nature characteristic of the fumes of burning sulfur, but resembles that of hydrogen sulfid, which other authors believe to be 328 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. the active substance. Other investigators claim that the active fumes are simply vapors of pure sulfur volatilized by the high temperature. The active fumes, whatever their nature, are given off in effective quantities only after the temperature of the air reaches about 75 F. Above this point they are given off the more actively the higher the temperature. Below 75 F. the fungus grows very slowly and the sulfur fumes are little needed, and, as the air warms up to a temper- ature at which the fungus grows rapidly, the fumes are given off in greater abundance. The lower the temperature the more slowly the fungus is affected. If the highest shade temperature of the day is between 75 and 80 F., it will require from seven to eight days to destroy all the mycelium. When the temperature rises to 90-95 F., the fungus commences to show signs of injury in 24 hours and in four or five days is destroyed. If the thermometer rises to above 100 F. in the hottest part of the day. one or two days are sufficient to completely rid the vineyard of the disease. In order to obtain these perfect results, however, the sulfur must be applied to every part of the vine. The nearer a spore or a piece of mycelium is to a particle of sulfur, the more quickly it is killed. Ex- cept in the hottest weather, the sulfur on one leaf is almost without effect on the fungus on a neighboring leaf. The utility, indeed the necessity, of a perfect distribution of the sulfur, especially in compar- atively cool weather, is apparent. The air is always hottest near the soil, and sulfur placed on the soil should give off more abundant fumes. Practice has shown, however, that sulfur placed in this position has almost no effect on the Oidium except in extremely hot weather. In such weather, sulfur is hardly ever needed in California, as it is usually accompanied by such a dry condition of the air that the fungus is killed without the aid of sulfur fumes. In exceptional cases, as for instance where very vigorous vines are growing in very moist places in the irrigated regions or when un- usually hot weather occurs in the coast regions, the air may be moist enough for the growth of Oidium even when the temperature rises to considerably above 100 F. In such cases it is sometimes desirable to sprinkle the sulfur on the ground instead of on the vines. The reason of this is that if the air is sufficiently hot the sulfur may injure both the fruit and the leaves of the vines. The fruit and leaves may be spotted and, in severe cases, may fall completely or in part. Such effects are to be feared, however, only when the temperature exceeds OIDIUM OR POWDERY MILDEW OF THE VINE. 329 110 F., or with varieties particularly susceptible to sulfur fumes, such as Isabella, Othello, and certain other American varieties and hybrids. If the earlier sulfurings are done properly, however, it will seldom be necessary to treat the vines in such weather and we may consider that the sulfur which goes on the ground is almost completely wasted. Effects of Sulfur on the Vine, Fruit, and Wine. The effect of sulfur on the vine is in no way injurious except under the conditions already noted. On the contrary, most observers concur in noting im- provement in the health and vigor of the vines after sulfuring irre- spective of the control of mildew. Whether this is due to some stimu- lating action of the sulfur on the foliage or to its action on the plant food in the soil is in doubt. The favorable influence of sulfuring the vines, while in blossom, on the setting of the fruit is even more generally recognized. If Oidium is present, this is easily accounted for by the prevention of the action of the fungus on the blossoms. The effect, however, is noticed even when no Oidium exists in the vineyard. The tendency of many vari- eties to " coulure," dropping their blossoms without setting, can be lessened by vigorous sulfuring during the blossoming period. Whether this is due to a stimulation of the floral organs under the action of the .sulfur, to the destruction of unrecognized fungi on the blossoms, or merely to the mechanical action of the current of air produced by the blowers in promoting pollination has never been determined. Heavy, late sulfuring may introduce notable quantities of sulfur into the wine. This sulfur is apt, under the influence of the yeast, to give a disagreeable odor of sulfureted hydrogen to the wine. This odor is usually temporary and disappears after a few rackings of the wine. When the sulfuring is done with a suitable machine, however, .so little sulfur is placed upon the grapes that this danger is not to be feared. Properly sulfured vines ripen their grapes from 7 to 10 days earlier than those attacked by Oidium. This is probably due to the better health of the vines, which allows the fruit to develop more quickly and more perfectly. Proper time and Weather for Sulfuring. The time of day at which the sulfur is applied is of little importance, provided the weather is suitable. It may be applied when the leaves are dry or when they are moist with dew. It is less effective, however, if the leaves are very wet, as the drops of water have a tendency to gather the sulfur into patches -and leave parts of the leaf untreated. 330 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. It is impossible to do the work perfectly in a high wind, but a gentle breeze is an aid in making the sulfur penetrate to all parts of the vine. Rain or very heavy and continued winds following immediately after the sulfuring will remove most of the sulfur before it has pro- duced the desired effect on the fungus, and the treatment must be re- peated. Each sulfuring should be followed by from one to four days of warm weather before the sulfur is removed by rain or wind. One or two days at or about 90 F. to 95 F., maximum shade temperature, or four or five days between 85 F. and 90 F. will usually give satis- factory results. If rain comes before the sulfur has been subjected to such temperature, the vines must be resulfured. As already noted, sulfuring in excessively hot weather should be avoided on account of the danger of burning grapes or foliage. For the same reason, any cultivation or other disturbance of the vines should be avoided in hot weather immediately following the application of sulfur. Proper Season for Sulfuring. The proper season for sulfuring will depend on the number of sulfurings needed. This number will differ- according to locality, weather, variety, and the exposure of the vine- yard and will vary from one to three in the interior valleys to from two to five in the coast valleys, or even as high as six or seven with susceptible varieties, in bad seasons in close proximity of the coast. The most necessary and effective sulfuring of all, and one which should never be omitted under any conditions, is at the time when the vines begin to open their blossoms. Even with the most resistant vari- eties, in the least affected districts, this sulfuring should be applied. Even where there is little or no danger of Oidium, the gain in better- setting of the fruit has been so frequently demonstrated that it amply repays the outlay. As all varieties do not blossom at the same time, the mixing of varieties in the same block should be avoided, for this and other reasons. Number of Treatments. In the interior, if this sulfuring were reg- ularly and universally applied, it would usually be sufficient. As many growers totally neglect sulfuring, however, there is danger of reinfec- tion from neighboring vineyards during the early summer. The vines should be watched, therefore, and upon the first signs of Oidium, a second sulfuring should be applied. This will usually be at the time the grapes are about the size of buckshot. Later than this there is little danger usually, as the air becomes too hot and dry for the growth of the fungus. The vines should be watched, however, especially those- OIDIUM OR POWDERY MILDEW OF THE VINE. 331 in moist parts of the vineyard near irrigation ditches or in the shade of trees. Very vigorous vines or susceptible varieties in cool seasons also may exceptionally require another sulfuring just before the grapes commence to color or to soften. These late sulfurings, however, are dangerous in the hot districts for reasons already given, and can nearly always be avoided if the earlier treatments are applied properly and in time. There are cases where it is advisable even in the interior to give the vines a sulfuring before the blossoming time. If the vines were badly attacked during the previous season there will be an abundance of spores in the vineyard and much injury may be done before the blos- soming time if the spring is warm. In such cases, it is best to give an early sulfuring at the time the vine shoots are about 6 to 8 inches long. For this sulfuring it is very necessary to choose suitable weather. If unfortunately this treatment is followed by rain or continued heavy winds without any intervening warm days, it should be repeated. This early sulfuring is very useful also in destroying the mites causing erinose?- a disease which often does considerable damage to the vines before the weather is warm enough for very rapid growth of Oidium. The erinose attacks with particular intensity Mission and Flame Tokay. In the coast valleys, Sonoma, Napa, Santa Clara, etc., two sul- furings should always be given ; the first at the time the shoots are from 6 to 8 inches long. This treatment might be omitted in dry, well ventilated situations with resistant varieties, if sulfuring were univer- sally practised throughout the district, but it is at present always safer to apply it. The second sulfuring should be at blossoming time. In dry early summers, except with the most susceptible varieties such as Carignane, a third sulfuring will often be unnecessary. The vine should be carefully watched, however, and, on the first appearance of mildew, sulfur applied again. In bad seasons a fourth sulfuring just before the commencement of ripening may be necessary. By watching the parts of the vineyard which experience has shown to be the most quickly affected, it is always possible to control the disease before it has done any serious damage. After the grapes have commenced to ripen, they are almost safe from the attacks of Oidium, but it is a mistake for this reason to allow the fungus to become abundant on the leaves, as it may in warm, moist autumns. Though such a late attack may do little or no damage to the 1 See Bulletin No. 136, < ' The Erinose of the Vine. 332 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. current crop, it will injure the buds and canes on which the crop of the following year depends. Moreover, it is this late growth of mildew which produces the winter spores and promotes an early and severe attack of the disease during the following spring. The vines therefore should be kept free from Oidium even if it requires a sulfuring after the grapes are gathered. In the coast districts where weather conditions similar to those of Berkeley exist, even three sulfurings will seldom be sufficient to hold the Oidium completely in check. "Where the springs are warm and the summers comparatively cool and moist, as along the coast of Santa Cruz, the fungus finds conditions favorable to its development at all times of the year when the vines are in leaf. In such locations an early sulfuring, when the shoots are 3 or 4 inches long, another at blossoming and a third when the grapes are the size of buckshot are always neces- sary. If these are thorough and there are no neighboring neglected vineyards to spread continuous reinfection, certain varieties may be kept free in good years by three sulfurings. It will, however, usually be necessary to interpolate another treatment between the first and that at blossoming time and follow the third with one or two supple- mentary treatments. Sulfuring Young Vines. Young vines, whether in the vineyard or the nursery, should not be neglected. In the nursery they are pecu- liarly susceptible owing to their nearness to each other and to the moist air near the irrigated soil. Autumn sulfuring is nearly always useful in this case to keep the leaves healthy until they have ripened the canes. Young vines during the first year in the vineyard are seldom seriously injured by mildew, but it is advisable to sulfur them at least once dur- ing the early summer. Methods of Applying Sulfur. From what has been said of the action of sulfur on the fungus, it is clear that thorough distribution is the main factor in its effective application. Providing we get some sulfur on every part of every vine in the vineyard, the amount we use is of little importance in controlling the disease. Whatever the fumes may be which are given off, the amount of sulfur used in producing them is infinitesimal. The smallest quantity of sulfur we can possibly use in practice is amply sufficient if we ac- complish the object of leaving no part of the vine untouched. On a properly sulfured vine the distribution is so perfect that on close examination we are unable to find a square inch of surface free from sulfur grains. On the other hand, if on looking at a vine from a distance of twenty feet we can see any signs of the sulfur applied, more than enough has been used. OIDIUM OR POWDERY MILDEW OF T"HE VINE. 333 If the distribution is defective, we not only fail to free* all parts of the vine from the Oidium but we leave enough of the fungus to spread rapidly through the vineyard as soon as the sulfur has been removed by rain or wind. Two or three incomplete sulfurings which fail to reach a number of whole vines or parts of vines are often less effective than one thorough treatment which leaves no part of any vinje un- touched. The methods used in California for sulfuring vines are the fol- lowing : 1. Throwing the sulfur on the vines by hand; 2. Distributing by perforated cans of various forms ; 3. Shaking through the tissue of a cloth sack ; 4. Various forms of hand bellows ; 5. Various forms of knapsack bellows ; 6. Traction sulfur distributers. The disease can be completely controlled by any of these methods. They differ only in the amount of labor, sulfur, and care necessary in applying them. In these respects, however, they differ very notably. 1. Throwing on by hand is undoubtedly the most laborious, dis- agreeable, and wasteful. Something like 90 per cent, or more of the sulfur is wasted because most of it goes on the ground, and of that which goes on the vine a few leaves usually receive the bulk. When the vines are large, if all parts of the vine, extremities of canes and center of head, are properly treated, from five to twenty times as much sulfur will be used as by the best methods. It also requires more time than the better methods. It is moreover very difficult to get men to sulfur effectively by this means owing to the large amount of sulfur they get into their eyes and mouths. They are naturally apt to think more of protecting themselves than of destroying the mildew. 2. Distribution from perforated cans is perhaps the commonest method of application. It is a little better than hand throwing, but wastes a great deal of sulfur. With large vines from five to ten times as much is used as is necessary. It is very difficult to reach the tops of high vines with the ordinary forms of cans. Some sulfur cans are made with a long handle, which obviate this defect to some extent but increase the difficulty of sulfuring the low parts and center of the vine. In both these methods it is unnecessary to use the best brands of sulfur, as with complete distribution so much is used that there is always enough fine material, except with the worst grades, to do the work. Some growers mix the sulfur with lime, ashes, road dust, or some inert powder to save sulfur. The main objection to this is that it involves the carrying and distribution of useless material. 334 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 3. An improvement on the last method is the use of a sack from which to shake the sulfur on to the vine. This sack should be made of cloth whose texture is close enough to permit only fine particles of sulfur to pass, but not so close as to require too much labor in shaking out the required amount. A sack about 14 inches long and 5 inches in diameter, holding about 3 pounds of sulfur when half full, is a con- venient size. Somewhat tightly woven grain sacks of good quality are suitable material from which to make them. Very good work can be done with sacks of this kind while the vines are small. Their main defects are that they hold very little and much time is wasted walking to the sulfur supply to fill them. They wear out very quickly and the work with them is laborious. They cannot be used while the vines are wet, as moisture on the sacks prevents the sulfur from coming out. For large and high vines they are even less suitable than the cans. It is almost impossible to sulfur any part of a vine higher than the workman's head. 4. The use of small hand bellows similar to that shown in fig. 9, b is a great improvement over the three methods just described. The distribution of the sulfur is much better, the workman less troubled by the sulfur, and every part of the vine can be reached. The main defects of these bellows are that they are very tiring to the hands and arms, and as they hold little sulfur much time is wasted in filling them. While not so wasteful of sulfur as the above methods, they use more sulfur than is necessary. 5. The best knapsack bellows are a great improvement on the hand bellows. These machines are known as "dust sprayers," "sulfuring machines," etc. There are several hand "dust sprayers" of American manufacture which were originally designed for the distribution of paris green. The current of air by which the powder is blown on to the plant is pro- duced by a rotary fan. The powder is stirred by various devices in the different machines and blown out of a reservoir through a tin or rubber tube. The machines made in Europe specially for the distribution of sulfur differ from the above principally in the method of producing the current of air. This is produced by a valve bellows similar in prin- ciple to the old-fashioned blacksmith's bellows. All the available American machines and one of the best European machines were tested this year by the Experiment Station. None of the American machines was found suitable for the purpose. They were OIDIUM OR POWDERY MILDEW OF THE VINE. Fig. 9. Various forms of Hand Sulfur Distributers. , Upper left hand, European machine. &, Upper right hand, sulfur bellows, c and d, Lower figures, American machines. nearly all extremely cumbersome and wasteful of sulfur. The best of those tested is shown by the photograph of fig. 9, d. They all have several very serious defects for the purpose tested. The regulation of the flow of sulfur is very imperfect and it is necessary to use an unnec- 336 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. essarily large quantity in order to cover the whole vine. This is espe- cially true in the case of high vines. The machines worked fairly well only when the outlet tube was held in a downward direction. While treating the tops of high vines the sulfur accumulates in the tube, which finally chokes up. In order to clear the tube it is necessary to hold it down, upon which the accumulated sulfur runs out and is wasted on the ground. The European machine, on the contrary, gave most excellent results. (See fig. 9, a.) The regulation device enables the operator to govern the amount of sulfur blown out with great precision. This is a very Fig. 10. Sulfur cloud to cover the whole vine. important point, as it makes it possible to use various grades of sulfur effectively and economically. The reservoir of the machine holds enough sulfur to treat two or three acres without refilling, but is less fatiguing to carry than the other machines, which hold only one- quarter as much. The sulfur is blown out in a fine impalpable powder (see figs. 10, 11, and 12), and owing to the form of the machine it can be applied to any part of the vine. By standing a little distance from the vine a single puff can be made to distribute the sulfur over the whole exterior of the vine. (See fig. 10.) Then after poking the end OIDIUM OR POWDERY MILDEW OF THE VINE. 337 of the tube into the center of the vine another puff will thoroughly sulfur the interior. (See fig. 11.) By a small attachment placed on the end of the tube the cloud may be forced upwards and the under side of the leaves more thoroughly treated (see fig. 12), but this is seldom necessary. The work is much less laborious than with any of the other methods tried and the workman is less liable to be troubled by the sulfur getting into his eyes. Fig. 11. Sulfuring interior of the vine. Fig. 12. Sulfuring the under side of leaves. A machine made in San Francisco on the plan of the European machines was found excellent in all respects except that it lacked the regulating device. The following table shows some of the results obtained with the various methods of sulfuring : 338 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. SULFUE AND TIME TAKEN TO SULFUK 500 VINES (1 ACKE). Mot^nri 2 year old Vines 3 year old Vines 4 year old Vines Ibs. ofS. time: min. Ibs. of S. time: min. Ibs. of &. time: min. A 4.82 30 8.4 56 B 8.61 30 11.1 63 C 6.56 33 12.7 56 D 9.84 30 23.9 65 E 9.43 33 28.6 60 F 6.56 33 28.9 58 G 12.30 30 42.8 69 A. European knapsack bellows. (Fig. 9, a.) B. San Francisco knapsack bellows. C. Hand bellows. (Fig. 9, 6.) I). American dust sprayer (the best of those tested). (Fig. 9, d.) E. Sulfur sack. F. Perforated can. G. Hand distribution. Each of the results given in the above table is the average of four tests made by four men and may be accepted as accurate so far as the amounts of sulfur are concerned. The time given for sulfuring, how- ever, is less accurate. The four men doing the sulfuring worked to- gether with different machines, so there \vas a tendency for the man with the most laborious machine to work harder to keep up with the others. This makes the difference in time between the various methods less than it would be in practice. No account, moreover, was taken of the time needed to go for sulfur and to fill the machines. This would still further increase the differences in time. In all the tests made, the vines were given as complete a sulfuring as was possible with the means employed. A fair sample of sublimed sulfur was used. ESTIMATE OF COST OF SULFUKING 500 MATURE VINES. Method 1st S. Ibs. line 5.0 7.0 2nd S. Ibs. 7.5 13.0 20.0 30.0 3rd S. Ibs. 10.0 20.0 30.0 50.0 Total S. Ibs. 22.5* 40.0f eo.ot 87.0f Cost Labor at of S. $2 per day .56 .60* .80 .60 $1.20 .60 1.74 .60 Total cost $1.16 1.40 1.80 2.34 10.0 L 7.0 Hand bellows Dust sprayer Perforated can Hand distribution .. .. 12.0 40.0 75.0 127.0f 3.54 .60 4.14 * Sulfur of good quality at $2.50 per 100 Ibs. t Sulfur of medium quality at $2 per 100 Ibs. j The time required will vary from three-quarters of an hour to one and one- half hours per acre (500 vines), according to the size of the vines and the method used. An average of one acre an hour is taken for the three sulfurings for all the machines. In practice it would probably be less than this for the best machines and more for the inferior methods. OIDIUM OR POWDERY MILDEW OF THE VINE. 339 The above estimates are based on the tests made, tests which proved effective in completely controlling the disease. The amounts indicated for an acre when the European machine is used are less than is recommended by the best authorities in the south of France. Viala in ' ' Les Maladies de la Vigne ' ' gives 15-30-40 kilos as the amounts to be used for the three sulfurings of an hectare. This corresponds to about 75 pounds to the acre. The vines in the south of France, how- ever, are planted much closer than ours, usually about 1,800 to the acre. The amount for 500 vines therefore would be a little less than our tests indicate. Cost of Treatment. The total cost for sulfur ing, including mate- rial and labor, will vary, if the best hand machine is used, from about 50 cents per acre for one treatment in the interior to $1.25 for three treatments in the coast valleys, or $2 to $2.25 for five treatments in the most affected localities. Power and Traction Machines. No machines of this description have been tested by the Experiment Station for the sulfuring of vines. In Europe it is only lately that they have been used at all. The diffi- culties attending the distribution of large quantities of sulfur in a fine cloud by means of a current of air are very great. It is claimed by the manufacturers of several machines that these difficulties have been overcome, but the machines are very costly. Moreover, it is hard to conceive of a machine which would do the work effectively without wasting a large part of the sulfur. When the vines are small, if the sulfur were thrown over a large area, as much would go on the ground as on the vines. As the vines when they first start cover only from 5 per cent, to 10 per cent, of the area, the amount of sulfur used by the power machine would be from ten to twenty times times as much as is necessary. As the cost of sulfur and of labor are epproximately equal with the best knapsack machine, no saving in cost of labor would offset this waste of sulfur. When the vines are large it is doubtful whether any machine could throw the sulfur as effectively into the interior of the vine where it is most needed as can be done with the tube of a knapsack machine. There is one consideration which makes it seem possible, however, that an effective power machine might have its uses here. There is nothing more expensive than losing the crop, and a power machine might make it possible to sulfur a vineyard and save the crop when it was impossible to have the work done by hand. Even at an extra cost of several dollars per acre this of course would be an advantage. Quality of Sulfur. Any kind of sulfur in the condition of a pow- 340 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. der will control the disease if used as directed. Coarse powders, how- ever, must be used in much greater quantities and are more difficult to apply properly. The absolute purity of the sulfur is of little impor- tance, provided there is no large adulteration with inert and useless substances such as gypsum. Many samples of sulfur were received at the Experiment Station during the past year and examined. Most of these samples were sent by grape growers. They were all found to be practically pure and unmixed. In the important matter of fineness, however, they differed widely. Two or three of them were so coarse as to be almost valueless for sulfuring vines. (See fig. 16, Sulfur No. 8.) A few were very good and most of them were passable. The prices quoted by the senders were little indication of the value of the samples. Some of the cheapest were of excellent quality for the purpose (see fig. 15, Sulfur No. 16), and some of the most expensive were among the worst (see fig. 16, Sulfur No. 8). This shows the need of a careful examination before purchasing. Some of the results of our examinations are shown in the following table : SAMPLES OF SULFUE KECEIVED AND EXAMINED BY THE STATION IN 1906. No. 30 Oy 3 20 19 28 26 15 24 6 29 13 18 4 16 31 23 25 10 17 5 21 27 12 1 7 2 11 14 8 Price C 66.8 60.8 $52.50 60.0 45.00 58.8 70.00 52.0 41.00 50.8 50.0 49.2 43.00 48.0 55.00 47.6 60.00 46.0 44.00 45.6 42.8 55.00 40.0 32.00 51.6 46.8 46.0 45.00 46.0 30.00 45.6 45.6 40.00 45.2 45.00 45.0 30.00 44.5 39.6 44.00 37.6 45.00 37.6 47.50 37.2 36.0 34.4 47.50 34.0 Sublimed, very fine, no coarse material. Sublimed, very good, very little coarse material. Sublimed, very good, some coarse material. Sublimed, very good, some coarse material. Sublimed, good, but with many large grains. Sublimed, good, but with considerable coarse material. Sublimed, good, but with considerable coarse material. Sublimed, good, but with some coarse material. Sublimed, fair, about one-third of coarse material. Sublimed, fair, but some coarse angular material. Sublimed, fair, with considerable coarse material. Sublimed, fair, with considerable coarse material. Sublimed, with much medium coarse material. Sublimed, with much coarse material. Ground, good, with little coarse material. Ground, good, with about one-third coarse material. Ground, good, with about one-third medium material. Ground, fair, about one-half fine material. Ground, good, except for some large particles. Ground, good, but considerable coarse material. Ground. Ground, fair, about one-half fine material. Ground, fair, about one-half fine material. Ground, much coarse material. Ground, much coarse material. Ground, fair, much coarse material. Ground, coarse. Ground, poor, very little fine material. Ground, very poor, hardly any fine material. Ground, principally large particles. OTDIUM OR POWDERY MILDEW OF THE VINE. 341 Fig. 13. Sublimed Sulfur of very good quality. Sulfur No. 30. Fig. 14. Sublimed Sulfur of poor quality. Sulfur No. 4. 342 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Fig. 15. Ground Sulfur of good quality. Sulfur No. 16. Fig. 16. Ground Sulfur of very bad quality. Sulfur No. 8, OIDIUM OR POWDERY MILDEW OF THE VINE. 343 The data given are the prices and the results of the Chancel test, column C, and of the microscopical examination. The Chancel test is the determination of the amount of settling that occurs when 5 grams of sulfur are allowed to stand in a cylinder after shaking up with 25 cubic centimeters of ether. The number represents the percentage of the height of the cylinder occupied by the sulfur after settling. It is a very convenient and quick method of testing the fineness of the sul- fur. (See fig. 17.) 30 28 4 16 8 FIG. 17. Comparative volumes of 5 grams of different sulfurs. No. 30. Sublimed Sulfur, Chancel No. 66.8 $70.00 No. 28. Sublimed Sulfur, Chancel No. 50.8 ... 41.00 No. 4. Sublimed Sulfur, Chancel No. 40.0 55.00 No. 16. Ground Sulfur, Chancel No. 51.6 32.00 No. 8. Ground Sulfur, Chancel No. 38.0 47.50 The numbers corresponding to good commercial sublimed sulfur are 50 to 70 ; those of the finest quality show 75 to 90. Powdered or 344 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. ground sulfur of the best quality will show from 60 to 70, and those of ordinary quality 43. 1 All the sulfurs examined, with the exception of two of the ground samples (Nos. 8 and 14), contained sufficient fine material to do effec- tive work, but the amount it would be necessary to use of the various grades would vary considerably. If the sulfur is applied by hand or with perforated cans, any of the sulfurs except Nos. 14 and 8 would probably be nearly equally good, and therefore the cheapest would be best. If we use several times as much as is needed, as w r e must \vith these methods, it matters little if 25 per cent, or 50 per cent, of the sulfur is useless. When using an effective sulfur machine it is possible to utilize the superior^ of the finer grades, and in this case it is undoubtedly ad- visable to use the better qualities. (See figs. 13 and 15.) A few simple directions for the examination of sulfur may be of use to the grower. 1. The finer the sulfur the more bulky. Therefore if several sul- furs are in sacks of equal weight, the largest sack will contain the finest sulfur. A 110-pound sack of good flow r ers of sulfur is twice as large as a 110-pound sack of very coarse ground. The difference in bulk between equal weights of sulfurs of various qualities is shown in fig. 17, representing the Chancel test. 2. The color of sublimed sulfur is a clear, bright yellow. The color of ground sulfur will vary with the fineness. Coarsely ground sulfur is almost of the same color as sublimed. When finely ground, the color becomes whitish. The whiter a ground sulfur, the finer it is. provided the color is not due to adulterants. 3. A good sublimed sulfur should feel as soft as flour when rubbed with the fingers in the palm of the hand. If hard particles are felt, the sulfur is not of the best quality. Ground sulfur always feels a little gritty, but the hard particles should not be large or numerous. 4. A very good idea of the fineness of a sulfur can be obtained by the use of an ordinary good hand magnifying glass costing about $1. A magnification of 10 or 20 diameters is sufficient. With a little expe- rience sublimed and ground sulfur can be distinguished by this means. The particles of sublimed sulfur are all nearly spherical with smooth outlines. Those of ground sulfur are irregular and with sharp edges. The sulfur is most easily examined when spread on a piece of glass over a dark background. A good way to spread the sulfur is to place Yiala, P., Les Maladies de la Vigne, p. 53. OIDIUM OR POWDERY MILDEW OF THE VINE. 345 a small pinch on the glass, wet it with a few drops of ether, and shake. This will distribute the sulfur in a thin layer over the glass and much facilitate the examination. 5. A test of the purity may be made by burning a pinch of the sulfur on a piece of white porcelain a broken plate, for example. To make the burning complete, hold the piece of plate over a lamp or on top of a very hot stove. A pure sulfur burns away completely, leaving only a black stain on the plate. Any dust or particles that are left indicate adulteration. The fine sulfurs are superior in three important respects: (1) They capable of more perfect distribution; (2) they offer a larger surface to the air and therefore give off more fumes; (3) they adhere better to the leaves. A pound of a very fine sublimed sulfur such as No. 30 (see fig. 13), the particles of which measure .01 mm. in diameter, if evenly distrib- uted and none lost, would give about 15,000 particles for every square inch of leaf and cane surface on an acre of large vines. A pound of a very coarse sulfur such as No. 8 (see fig. 16), the particles of which have twenty-five times as large a diameter, would supply only about one particle for every square inch. Moreover, a much larger propor- tion of the coarse sulfur would be lost by failing to adhere to the leaves and falling on the ground. Perhaps the most important advantage of the finest sulfur in this respect is that the impalpable powder floats so lightly in the air that it reaches and adheres to the lower surfaces of the leaves and canes. A finely powdered sulfur such as No. 16 (see fig. 15) would probably be just as effective as the sublimed, for though it contains a certain proportion of coarser particles, the finer material has not the tendency to cohere in the groups of particles characteristic of sublimed sulfur. The quantity of fumes given off by a sulfur must be about in the proportion of the extent of surface which the particles present to the air. This surface is inversely proportionate to the diameter of the par- ticles. A pound of sulfur, No. 30 or No. 16, would possess a surface twenty-five times as great as that of No. 14, and would therefore give off fumes much more rapidly and in greater quantity. OTHEE METHODS OF TREATMENT. Combined Treatments. Various other substances and sprays have been suggested and tried for the control of the Oidium during the growing season. There are two cases in which it has seemed desirable to attempt to find another method of control. One of these is where it 346 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. is necessary to treat for another vine disease which cannot be con- trolled by sulfur at the same time. In Europe, where spraying with copper solutions is necessary to protect the vines from Peronospora, Black Rot, and Botrytis, various sprays have been tried with the object of controlling the Oidium at the same time. These sprays are princi- pally liquids containing Bordeaux mixture, copper sulfate, or sulfoste- atite together with "wetable" sulfur. There is considerable uncer- tainty as to the success of these combinations, and as the diseases they are intended to reach do not exist in California they are of little in- terest to us. The other case is where sulfur has been found ineffective or too slow in its action. This seems to be the case in the Eastern States, and may be in certain parts of the coast region of California or perhaps exceptionally in other regions in abnormal years. Liquid Sprays. Dry sulfur to be effective requires warm weather. If the weather is cool its action is slow or nil. Certain sprays act im- mediately on the Oidium whatever the temperature. It should be re- membered, however, that the Oidium grows very slowly or not at all below temperatures at which sulfur is effective. Cases, however, may arise where, through neglect of proper sulfuring, the vines may be badly attacked by mildew, and owing to the coolness of the weather when the trouble is first perceived sulfur may act too slowly. In such cases it may be advisable to use a quick acting spray. Such a condition might occur in a cool late spring. Another case in which a spray may be useful is where the vines have been very badly affected the previous autumn and the canes are covered with winter spores and perhaps hibernating mycelium ready to infect the new shoots on the first warm day. A spraying just as the buds swell might be of help in such a case. 1 Spraying in the summer should never be necessary, as the heat is sufficient to cause the sulfur to act quickly. It has been suggested that late sulfuring is inadvisable because it may cause spotting of the grapes. If the grapes have not commenced to ripen this will not occur if the sulfur is applied properly, and if they have commenced to ripen they are safe from the disease, and sulfuring to protect the vines should be deferred until the grapes are gathered. No sprays, however, do the work as thoroughly as sulfur. A spray only kills the fungus which it actually touches, and the most perfect spraying possible will leave some parts of the vine untouched. Where 1 Tests of winter spraying by Pacottet and Eavaz in France gave no favorable results. OIDIUM OR POWDERY MILDEW OF THE VINE. 347 a spray is used it should therefore be followed by an application of dry sulfur to complete the work. The sprays which have been found most effective for this purpose are Bordeaux mixture, permanganate of potash, and alkaline polysul- fids. Vines are not easily injured by copper salts, so that a strong Bordeaux can be used. The 6-4-50 formula would be suitable. Permanganate of potash at the rate of one pound to 100 gallons of water has been found effective. A little chloride of potash or common salt improves the spray by increasing its adhesive qualities. Liver of sulfur at the rate of 4 pounds to 100 gallons of water with 4 pounds of soap has also been used with success. Alkaline polysulfids have also been used effectively in the same way. These sprays are more permanent in their effects than the copper and permanganate mixtures because a small amount of finely divided free sulfur is set free, which acts in the same way as the powdered sulfur when applied in the usual way. It is very probable that a weak lime-salt-sulfur spray such as is in common use on fruit trees would be equally effective. WINTER TREATMENT. As the fungus passes the winter, when it has no green leaves to grow on, in the form of resting spores on the canes and in the soil and perhaps of resting mycelium under the bud scales, it has been sug- gested that a winter treatment which would destroy these hibernating forms would be the best method of control, or at least that it would much simplify the summer treatment. The methods usually proposed are to spray the vines after pruning with the lime-salt-sulfur used for fruit trees or with a 2 per cent, solu- tion of bluestone. Others advise swabbing the vines at the same time with a saturated solution of iron sulfate (copperas) acidified with 1 per cent .of sulfuric acid. To make the treatment more thorough, some remove all the dry bark of the vine by means of scrapers before treat- ment. This is supposed to destroy all the perithecia on the vine. In order to prevent infection from the hibernating mycelium under the bud scales it is further advised to spray the vines with Bordeaux mix- ture just as the buds swell in the spring. Such treatments as these are of course very expensive and cost more than several sulfurings, so that, unless they can be proved to be effective, they should not be adopted. There is considerable evidence that such treatment makes the vines more vigorous and healthy, but that it has any effect on controlling the Oidium is doubtful. It seems unnecessary, because if we control the Oidium in the summer, as we 348 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. must do to save our crop entirely, there will be no winter spores formed and, therefore, no use in spraying for them. Winter treatment, moreover, cannot be completely effective because, however well done, it cannot destroy all the resting spores, because most of them are in the soil, and if but a few escape, they are capable of infecting the whole vineyard when the weather conditions are favor- able. Sulfuring, therefore, is necessary even when winter spraying is practised. There is reason to believe, moreover, that winter treatment is com- pletely ineffective. Every other vine in a small patch of vines at Berkeley was treated last winter with bluestone, iron sulfate, or Bor- deaux mixture. In the spring just as much mildew was found, on its first appearance, on the treated as on the untreated vines. A still more convincing experiment is described in the "Revue de Viticulture," No. 655, page 12. This seems to prove as well as a single experiment can : First, that the fungus does not pass the winter to any extent in the summer form under the bud scales ; and second, that the most thorough winter treatment is useless if no winter spores are formed, and completely ineffective if they are. Mr. Pacottet says in the article quoted : "In 1904 we observed that the spring attack of Oidium occurred first precisely in those hothouses of Nanterre where perithecia had been found in the autumn of the pre- vious year. The same fact was observed in 1905. This led us to make careful observations the following year on the manner and time of the appearance of the Oidium. "Oidium appeared at the end of March, 1906, and only in those grape houses, to the number of 20, where the presence of winter spores had been noted in November of the previous year. In these houses the fungus appeared with such intensity that nearly every leaf showed simultaneously several patches. "These observations acquire especial importance when considered in connection with the various hypotheses which have been advanced regarding the modes in which the Oidium passes the winter, especially as regards the hibernating of fragments of mycelium (summer form) adhering to the canes and capable of vegetating anew in the spring. "At Nanterre the disinfection of the vines is as complete as it is possible to make it. After removing the old bark they are treated with boiling water and swabbed with a 30 per cent, solution of iron sulfate. They are then covered with a paste of lime and sulfur. * * * Be- fore the starting of the buds, the walls, glass, and casings are disin- fected with strong washes and the air with the fumes of burning sulfur." OIDIUM OR POWDERY MILDEW OF THE VINE. 349 Now, even with such thorough winter treatment as this, which it would be quite impracticable to apply in a vineyard, no apparent effect was obtained in the control of the spring infection. The spring infec- tion was due, therefore, to spores which were not on any part of the vine, and from which no kind of spraying or swabbing of the vine would be any protection whatever. Pacottet concludes, therefore, that practically all the spring infec- tion is due to spores which have passed the winter in the soil. These are the spores contained in the perithecia which have dropped in the autumn with the leaves on which they are formed. His advice for hot- house treatment is to gather all these leaves before they fall and to burn them. This again is impracticable in a vineyard, and we are forced again to the conclusion that no form of winter treatment is of any use in the control of Oidium in vineyards, and that the only practicable method is proper sulfuring of the vines in spring and summer. This will' pre- vent injury to the vines, and if thorough will prevent the formation of winter spores. SUMMAEY. Oidium is one of the most serious diseases of the vine and the only serious fungus disease of vines in California. It is capable of destroying the whole crop in most vineyards in bad seasons if not controlled. Much more damage is done to vines and grapes in California than is usually supposed, but the control is much easier and more certain than in most vine-growing countries. The disease attacks leaves, canes, and fruit during the growing season. It grows only on the exterior green surfaces of the vine and passes the winter in the form of resting spores in the soil. Certain varieties of vines are very susceptible and others compara- tively resistant. Moist warm atmosphere favors the growth of the fungus. Methods of training, cultivation, and irrigation which keep the vine dry by thorough aeration minimize the danger of attack. Dusting the vines with sulfur is the cheapest and most efficient method of control in California. The weather and the season when the sulfur is applied are of great importance. 350 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. The number of treatments will differ with the locality, the season, and the variety of vine. Vines should be protected from late attacks even after the grapes are gathered. Young vines should be protected as much as old, even when they are in the nursery. The usual methods of applying sulfur by hand or with perforated cans is wasteful and uncertain. A good sulfur sprayer is essential for the best results. None of the American dust sprayers tried is suitable for the purpose. The "Ver- morel souf reuse Torpille ' ' was found to answer perfectly. The cost of treatment, when a good sulfur distributer is used, va- ries from 50 cents to $2.25 per acre, according to the number of treat- ments necessary. The cost is about equally divided between sulfur and labor. Traction machines do not promise any improvement in cost or efficiency. Finely divided sublimed or powdered sulfur should be used. Coarse sulfurs cost more because more is needed and they are less effective. No other form of summer treatment is so effective as sulfuring, but in rare, special cases a supplementary spray may be useful. Winter treatment is in all probability of no use in the control of Oidium. OIDIUM OB POWDERY MILDEW OF THE VINE. 351 STATION PUBLICATIONS AVAILABLE FOR DISTRIBUTION. REPORTS. 1896. Report of the Viticultural Work during the seasons 1887-93, with data re- garding the Vintages of 1894-95. 1897. Resistant Vines, their Selection, Adaptation, and Grafting. Appendix to Viticultural Report for 1896. 1898. Partial Report of Work of Agricultural Experiment Station for the years 1895-96 and 1896-97. 1900. Report of the Agricultural Experiment Station for the year 1897-98. 1902. Report of the Agricultural Experiment Station for 1898-1901. 1903. Report of the Agricultural Experiment Station for 1901-03. 1904. Twenty-second Report of the Agricultural Experiment Station for 1903-04. TECHNICAL BULLETINS--ENTOMOLOGICAL SERIES. Vol. 1, No. 1. Wing Veins of Insects. No. 2. Catalogue of the Ephydridae. BULLETINS. Eeprint. Endurance of Drought in Soils of the Arid Region. No. 128. Nature, Value, and Utilization of Alkali Lands, and Tolerance of Alkali. (Revised and Reprint, 1905.) 133. Tolerance of Alkali by Various Cultures. 140. Lands of the Colorado Delta in Salton Basin, and Supplement. 141. Deciduous Fruits at Paso Robles. 142. Grasshoppers in California. 144. The Peach-Worm. 147. Culture Work of the Sub-stations. 148. Resistant Vines and their Hybrids. 149. California Sugar Industry. 150. The Value of Oak Leaves for Forage. 151. Arsenical Insecticides. 152. Fumigation Dosage. 153. Spraying with Distillates. 154. Sulfur Sprays for Red Spider. 156. Fowl Cholera. 158. California Olive Oil; its Manufacture. 159. Contribution to the Study of Fermentation. 160. The Hop Aphis. 161. Tuberculosis in Fowls. (Reprint.) 162. Commercial Fertilizers. (Dec. 1, 1904.) 163. Pear Scab. 352 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 164. Poultry Feeding and Proprietary Foods. (Reprint.) 165. Asparagus and Asparagus Bust in California. 166. Spraying for Scale Insects. 167. Manufacture of Dry Wines in Hot Countries. 168. Observations on Some Vine Diseases in Sonoma County. 169. Tolerance of the Sugar Beet for Alkali. 170. Studies in Grasshopper Control. 171. Commercial Fertilizers. (June 30, 1905.) 172. Further Experience in Asparagus Rust Control. 173. Commercial Fertilizers. (December, 1905.) 174. A New Wine-Cooling Machine. 175. Tomato Diseases in California. 176. Sugar Beets in the San Joaquin Valley. 177. A New Method of Making Dry Red Wine. 178. Mosquito Control. 179. Commercial Fertilizers. (June, 1906.) 180. Resistant Vineyards. 181. The Selection of Seed- Wheat. 182. Analyses of Paris Green and Lead Arsenate. Proposed Insecticide Law. 183. The California Tussock Moth. 184. Report of the Plant Pathologist. 185. Report of Progress in Cereal Investigations. Circulars. No. 1. Texas Fever. 2. Blackleg. 3. Hog Cholera, 4. Anthrax. 5. Contagious Abortion in Cows. 7. Remedies for Insects. 9. Asparagus Rust. 10. Reading Course in Economic Entomology. (Revision.) 11. Fumigation Practice. 12. Silk Culture. 13. The Culture of the Sugar Beet. 15. Recent Problems in Agriculture. What a University Farm is For. 16. Notes on Seed- Wheat. 17. Why Agriculture Should be Taught in the Public Schools. 18. Caterpillars on Oaks. 19. Disinfection of Stables. 20. Reading Course in Irrigation. 21. The Advancement of Agricultural Education. 22. Defecation of Must for White Wine. 23. Pure Yeast in Wineries. 24. Olive Pickling. 25. Suggestions Regarding Examination of Lands. 26. Selection and Preparation of Vine Cuttings. 27. Marly Subsoils and the Chlorosis or Yellowing of Citrus Trees. Copies may be had on Application to DIRECTOR OF EXPERIMENT STATION, Berkeley, Calif. UNIVERSITY OF CALIFORNIA PUBLICATIONS. COLLEGE OF AGRICULTURE, AGRICULTURAL EXPERIMENT STATION, BERKELEY, CALIFORNIA. INSECTS INJURIOUS TO THE VINE IN CALIFORNIA. Phylloxera (Phylloxera vastatrix Plan.). Flea Beetles (Haltica sps.). Grape Leaf Hopper (Typhlocyba comes Say). Grape Leaf- folder (Desmia funeralis Hubn.). Imported Grape Root Worm (Adoxus vitis Leaf Chafers. Foureroy). Wire Worms. Hawk Moth Larvae. Erinose. Grasshoppers. Nematode Root Gall) Heterodera radicola Cut Worms and Army Worms. (Greef) Mull.). BY H. J. QUAYLE. BULLETIN No. 192, (Berkeley, Cal., October, 1907.) SACRAMENTO: w. w. SHANNON, : : : : SUPERINTENDENT STATE PRINTING. 1907. BENJAMIN IDE WHEELER, Ph.D., LL.D., President of the University. EXPERIMENT STATION STAFF. E. J. WICKSON, M.A., Director and Horticulturist. E. W. HILGARD, Ph.D., LL.D., Chemist. W. A. SETCHELL, Ph.D., Botanist. ELWOOD MEAD, M.S., C.E., Irrigation Engineer. C. W. WOODWORTH, M.S., Entomologist. R. H. LOUGHRIDGE, Ph.D., Agricultural Geologist and Soil Physicist. (Soils, Alkali.) M. E. JAFFA, M.S., Nutrition Expert, in charge of the Poultry Station. G. W. SHAW, M.A., Ph.D., Agricultural Technologist, in charge of Cereal Stations. GEORGE E. COLBY, M.S., Chemist. (Fruits, Waters, Insecticides.) RALPH E. SMITH, B.S., Plant Pathologist and Superintendent of Southern California Pathological Laboratory and Experiment Station. A. R. WARD, B.S.A., D.V.M., Veterinarian and Bacteriologist. E. W. MAJOR, B.Agr., Animal Industry and Manager of University Farm. F. T. BIOLETTI, M.S., Viticulturist. (Grapes, Wine and Zymology.) H. M. HALL, M.S., Assistant Botanist. H. J. QUAYLE, A.B., Assistant Entomologist. W. T. CLARKE, B.S., Assistant Horticulturist and Superintendent of University Extension in Agriculture. JOHN S. BURD, B.S., Chemist, in charge of Fertilizer Control. C. M. HARING, D.V.M., Assistant Veterinarian and Bacteriologist. J. W. MILLS, Assistant Horticulturist, ) Citrus Experiment station, Riverside. T. F. HUNT, B.S., " ) E. B. BABCOCK, B.S., Assistant Plant Pathologist. E. H. SMITH, M.S., Assistant Plant Pathologist. H. J. RAMSEY, M.S., Assistant Plant Pathologist, ) Southern California Pathologi- C. O. SMITH, M.S., " " f cal Laboratory. Whittier. R. E. MANSELL, Assistant in Horticulture, in charge of Central Station Grounds. GEO. W. LYONS, B.S., Assistant in Soil Laboratory. RALPH BENTON, B.S., Assistant in Entomology. A. J. GAUMNITZ, M.S., Assistant in Cereal Investigations. HANS C. HOLM, B.S., Assistant in Zymology. P. L. McCREARY, B.S., Laboratory Assistant in Fertiliser Control. C. WESTERGAARD, B.S., Assistant in Farm Mechanics. M. E. STOVER, B.S., Assistant in Agricultural Chemical Laboratory. RACHAEL CORR, M.A., Assistant in Cereal Laboratory. D. R. HOAGLAND, A.B., Assistant in Agricultural Chemical Laboratory. D. L. BUNNELL, Clerk to the Director. JOHN TUOHY, Patron, ) Tulare Substatiori( Tulare . J. T. BEARSS, Foreman, \ J. W. ROPER, Patron, ) University Forestry Station, Chico. E. C. MILLER, In charge, } \ U" 1 * Forest ^ Station ' Santa VINCENT J. HUNTLEY, Foreman of California Poultry Experiment Station, Petaluma. The Station publications (REPORTS AND BULLETINS), so long as avail- able, will be sent to any citizen of the State on application. INSECTS INJURIOUS TO THE VINE IN CALIFORNIA. BY H. J. QUAYLE. California, with its extensive areas of vineyards and lack of extremes in climate, offers suitable conditions for the development of a con- siderable number of insect pests of the vine. Here also the large plantings of the European, or vinifera, vines have given the phylloxera an opportunity to do greater damage than elsewhere in the United States. Of the two hundred and seventy-five insects we have recently listed as attacking the vine throughout the world, only a very few (a dozen or two) are really of any economic importance; all the others being, generally, but casual visitants. Two or three of these of economic importance attack the roots, while the remainder feed upon the parts of the plant above ground. The roots are sapped of their juices, rendered knotty, and caused to decay by the phylloxera. Strips or rings of the bark are eaten out by the root worm, and the fibrous roots are devoured by wire worms. The juices of the leaves are sucked out by the vine hoppers, irregular holes eaten away by flea beetles and leaf chafers, or chain-like strips by the root beetles ; the edges rolled by the leaf -roller, or the foliage devoured completely by hawk moth larvas, grasshoppers, cut worms and army worms. The young buds are destroyed by the flea beetle and by cut worms ; and the shoots, petioles, pedicels, and berries have chain-like furrows gouged out by the root beetle. With the possible exception of the root beetle, all the insects attacking the vines in this State are native American insects. The present bulletin is intended to give simply a popular account of the more important of these. More or less extended studies have been carried on during the past year on the vine hopper and root beetle, and these will be treated of in separate bulletins and only summary accounts given here. PHYLLOXERA.* (Phylloxera vastatrix Planchon.) Historical. The phylloxera is a native of the United States east of the Rocky Mountains, where it is found living upon the wild vines. It ir? a minute insect, related to the scale insects and plant lice. The insect was probably introduced into California upon vines, cut- tings or roots, imported from France, though it was possibly introduced * Revised from Bulletin No. 131, by F. T. Bioletti. 100 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. from several sources and at several points. It was first noticed in the southern part of Sonoma County, in the valley surrounding the old town of Sonoma, about 1874. By 1880 vines killed by the insect had been found in Napa, Solano, and Placer counties, and hundreds of acres had been pulled up in Sonoma Valley. Since then the insect has spread to all the important grape-growing regions of California north of Tehachapi*, and probably not less than fifty thousand acres have been destroyed. The Insect. The phylloxera occurs normally in four forms, which have been called by Victor Mayet: 1. The gall insect, or form of multiplication; 2. The root insect, or form of devastation; 3. The winged insect, or form of colonization ; 4. The sexual insect, or form of regeneration. The gall insect lives upon the leaves, and is the commonest form on the wild vines in the native habitat of the insect. It rarely or never occurs in California. In Europe it is found often upon American and rarely upon European varie- ties. It causes little swellings or galls upon the leaves and younger parts of the vine, which, though sometimes very numer- ous, do little permanent injury. The chief danger from the gall form is that it multiplies with astonishing rapidity and mi- grates from the leaves to the soil. Here it attacks the roots and gives rise to the root form, which is the "form of devastation," the one which finally destroys all the vines it attacks which are ' ' non-resistant. ' ' Every insect of the root form which reaches maturity lays about twenty-five or thirty eggs, each of which is capable of developing into a new egg-layer needing no fertilization. As there are from five to seven such generations during the year the increase in numbers is extremely rapid. Sometimes during the summer, usually in July or August, some of the eggs laid by the root insects may develop into insects of slightly different form, called nymphs. They are somewhat larger than the * The phylloxera is said to have been found once in Southern 'California, but as the vineyard was uprooted and destroyed the insect was probably extirpated. FIG. 1. Under side of grape leaf showing galls caused by Phylloxera. This form seldom, if ever, occurs in California. BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 101 normal root form and show slight protuberances on the sides, which finally develop into wings. These are the winged or colonizing insects, which emerge from the soil, and, though possessing very weak powers of flight, are capable of sailing a short distance, and if a wind is blowing may be taken many rods, or even miles. Those which reach a vine crawl to the under side of a leaf and deposit from three to six eggs. These eggs are of two sizes, the smaller of Avhich produce males and the larger females. The females arising from these eggs, after fertilization, migrate to the rough bark of the two-year-old wood, where each deposits a single egg, called the winter egg, which remains upon the vine until the fol- lowing spring. The in- sect which hatches from this egg in the spring goes either to the young leaves and becomes a gall-maker, or descends to the roots and gives rise to a new generation of egg-laying root-feed- ers. The normal and com- plete life cycle of the phylloxera appears then to be as follows: Male and female insects (one generation in autumn) ; FIG - 2 .Root'Form of Phylloxera, a, healthy root; 6, root on which the lice are working, representing the knots and swellings caused by their punctures ; c, root deserted by lice and beginning to decay ; d, d, d, show how the lice appear on the larger roots ; e, the nymph ; g, winged female. After Riley. gall insects (one to five generations while the vines are in leaf) ; root insects (an unknown number of generations throughout the year) ; nymphs, which become winged insects (one generation in midsummer). The gall stage may be omitted, as it generally is in California, and the insects which hatch from the fertilized eggs laid by the female go directly to the root and produce offspring, which are indistinguishable from the root form produced in the normal cycle. For how many generations the root form can exist and reproduce without invigoratioh supposed to come from the production of the sexual form is not known, but certainly for four years and probably more. The gall form on 102 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. American vines may probably be prevented by spraying the vines in winter to kill the winter eggs ; but this treatment has no effect on the root forms, which in California hibernate abundantly in the soil. All forms of the phylloxera are extremely minute, the root form being about one twenty-fifth of an inch long when it reaches the adult egg-laying stage, and little more than half this length when young and active. It is just large enough to be seen by the unaided eye in a good light when its presence is known, and, by the help of a glass magnifying five diameters, its legs and antennae are plainly visible. Its color is light greenish-yellow in summer, and somewhat darker in winter; so that when numerous the attacked roots appear as though dusted in spots with powdered mustard or cinnamon. The newly hatched insect is fairly active, and at first moves about from place to place on the roots, but finally, when it reaches the egg-laying stage, inserts its sucking-tube into the root and remains fixed. Nature of Injury. The amount of nutriment taken from the vine by such minute insects, even when present in the immense numbers in which they sometimes occur, is not sufficient to account for the dis- astrous effect upon* the plant. The death of the vine is due to the decay which sets in wherever the phylloxera inserts its sucking-tube, for a swelling is produced, composed of soft tissue, which soon decays. When this swelling occurs at the end of a young rootlet, growth in length is stopped ; when it occurs on larger roots, a kind of ' ' cancer ' ' or decay spot is finally formed, which soon extends around the root, and all below the point of attack dies t During the first year or two after a vine is attacked there is little apparent damage. In fact, the effect of the phylloxera is equivalent to root pruning, and in some cases results in an unusually large crop of grapes. The year after this crop, however, the vine having endured the double strain of heavy bearing and root injury, is unable to recuperate, and generally dies. In rich moist soil the death of the vine is not so sudden, and two or even more crops may mature after symptoms of the disease are evident. Methods of Dispersal. The ways in which new vines and vineyards become infested may be classed as natural and artificial. The natural ways may be inferred from what has been said of the life history of the insect. From a vine first attacked the root form spreads through the soil to neighboring vines slowly, but continuously, thus forming the so-called ' ' oil-spots. ' ' A typical oil-spot of several years ' standing will show several dead vines in the center, then a ring of vines with very short growth and no grapes, next another ring where the growth is not of normal vigor, but where the crop may be equal to or larger BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 103 than that of the healthy vines. Such a spot enlarges its area year after year at a gradually accelerating rate as the front of the invading army becomes longer. The rate of advance will vary with the soil and climate, but will probably never exceed forty or fifty feet annually. If this were its only method of spreading, the insect could be controlled or even exterminated with comparative ease. Unfortunately, it is able to spread much more rapidly by means of the winged form; and the rapidity of its extension over the south of France was due principally to this agency. In California, though the winged form has been found, it seems to be rare, especially in the central valleys, which probably accounts for the comparative slowness with which new districts have become infested. The artificial methods of dispersal here are probably more effectual in spreading the insect than the natural. The insects are taken from one part of the vineyard to another on pieces of the roots of infested vines adhering to the plows or other implements used in cultivation; while they are introduced into new localities on rooted vines or cuttings brought from infested districts. METHODS OF COMBATING THE PHYLLOXERA. The methods to be used in resisting this foe of the vineyardist may be divided into groups corresponding to different stages of infestation and to varying local conditions. There are three cases to be distin- guished, viz : 1. When the district is uninf ested ; 2. When a few small infested spots are known in the district; 3. When the district is badly infested; i. e., shows many and widely distributed infested spots, even though none of the spots are large. 1. In the first case, all efforts should be directed to keeping out the pest, and the only effectual means is a rigidly enforced embargo on all material capable of introducing it. Although the phylloxera, so far as known, feeds on nothing but the vine, there is always danger of eggs or insects being contained in the earth attached to any kind of root. This measure, consistently carried out, has kept the province of Algiers free from infestation, though the neighboring province of Constantine has been a prey to the pest for many years. 2. In the second case, where the insect has already obtained a foot- hold, the first step to take is to determine as nearly as possible the exact extent of the infested area. If it is found to be confined to a small, isolated vineyard, an effort should be made to completely eradi- cate the pest. This can be done only by destroying the vineyard, by subjecting it to what is called the "death treatment." This is best done (after grubbing up the vines and burning them on the ground) by making an embankment around the whole vineyard and then running water on to it until it is converted into a lake. The water 104 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. should be kept continuously at a depth of at least six inches until all the insects are destroyed. The best time to do this is in May or June, as at that time four weeks of continuous flooding is sufficient to kill both insects and roots. It is important that every root should be killed in order that, if any insect survives the flooding, it will die for lack of food. Where flooding is impracticable, the vines should be grubbed out and burned in the same way, and the ground kept clean of all growth for at least one year. This is in order that any suckers which may come up from the roots may be destroyed immediately. If crops, or even weeds, are allowed to grow, some of these suckers may escape observation and keep the insects alive to spread the pest the next year. If the affected spot is not too large it is well to disinfect the soil with bisulfid of carbon. This is applied by pouring one ounce each into holes placed two feet apart all over the land to be treated. These holes should be about one foot deep and can be made with a small crowbar or dibble. After pouring in the liquid, the hole should be closed by pressing the earth into it with the foot. If, however, the pest has obtained a foothold in several vineyards of the district, or in a large vineyard, it is practically hopeless to attempt to eradicate it. In this case all we can reasonably hope to do is to delay the spread of the pest as much as possible, and in the meantime to place all new vineyards on a permanently phylloxera-resistant basis. Every infested spot in the district should be diligently sought out and treated. The treatment consists in digging up and burning every vine in each spot which shows symptoms of attack, together with at least three rows of apparently healthy vines surrounding them. Disinfection of the soil of these spots by flooding or with bisulfid of carbon is then advisable wherever practicable, but in any case these spots should be strictly isolated in all farming operations. In cultivating the healthy parts of the vineyard, to pass through the infested spots with plows or hoes is a most effective method of accelerating the spread of the insect. The search for infested spots is most easily and thoroughly done in July, or August, as at that time the shortness of growth in the " oil- spots ' ' is most readily detected and the insects are easily found, as they are in large numbers on the surface roots and generally also on the trunk of the vine just below the surface of the soil. The search for and destruction of infested spots should be .repeated every year; and if commenced in the early stages of infestation and prosecuted with sufficient thoroughness in every vineyard throughout a district, will effectually prolong the life of the bulk of the vines for many years. As soon as the actual presence of the phylloxera in a district is known and all hope of permanently eradicating it is abandoned, the embargo should be modified to the extent of admitting vine cuttings. These BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 105 should be introduced, however, under strict quarantine regulations, including disinfection by responsible and properly instructed persons. Rooted vines, or cuttings with pieces of old wood attached, should still be kept out, as they can not be disinfected with any certainty. 3. However conscientiously and completely these measures are en- forced, a time will arrive sooner or later when the cost of inspection and eradication will be greater than any benefit to be derived from them. We are then face to face with the third set of conditions; we must accept the phylloxera as a permanent inhabitant of the district, and simply consider the best method of growing our vines in spite of its presence. By this time all embargo or quarantine regulations are useless and should be repealed. Of the many thousands of methods proposed and tested for maintain- ing a vineyard in spite of the phylloxera, but very few have been of the slightest practical value, and only four are at present used to any important extent. These methods are: 1. Injection of carbon bisulfid; 2. Flooding 'or submersion; 3. Planting in sand; 4. Planting resistant vines. The first two methods aim at destroying the insect; the last two at rendering the vines immune to their attack. As neither of the insecti- cidal methods can be applied with sufficient thoroughness to completely eradicate the pest without also killing the vines, the treatments have to be repeated every year in order to destroy the offspring of the few insects which escaped the treatment of the previous year. For this reason these methods are being abandoned everywhere, especially in all new plantings, in favor of the others, which after the vineyard is prop- erly started, involve no further expense; and as planting in sand is of very limited and local applicability, it may be said that at present the only method that need concern grape-growers in California very seri- ously is the use of resistant vines. Bisulfid of Carbon Method. Bisulfid of carbon is a liquid which volatilizes very rapidly at ordi- nary temperatures and gives off a poisonous and highly inflammable vapor. This vapor is heavier than air and therefore gradually replaces and saturates the air in the interstices of the soil when the liquid is injected. It is used at the rate of from one hundred and twenty-five pounds to two hundred and fifty pounds per acre, and may be applied at any time except during blossoming and ripening of the fruit. Two treatments, one directly after the vintage and the other a week or so before blossoming, give the best results. The liquid is applied by pour- ing from one-fourth to three-fourths of an ounce into holes made from 106 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 18 to 24 inches apart all over the vineyard, care being taken not to put any nearer than one foot from a vine. The holes are made from 12 to 15 inches deep, and are closed immediately after pouring in the liquid by pressing the soil with the foot. The holes may be made with an iron rod or dibble; but, where the method is employed on a large scale, special injectors are used, which much facilitate the work. The injections are best made when the soil is fairly firm, and when it is neither very wet nor very dry. This method succeeds only in rich, deep, loose soils, and can not be used successfully in soil containing much clay, or on dry, rocky hillsides or when the soil is saturated with moisture. It is most effective in sandy soils, where the nature of the soil is itself unfavorable to the insect. It is least success- ful in warmer locations, where the insect is most prolific and most harmful, and is used chiefly in the cooler locations where the phylloxera does least damage. Vines which are much weakened by the attacks of the insects can not be successfully treated, and all treated vines require fertilization and most thorough cultivation. The annual cost for material alone would be from $15 to $25 per acre; at the present market price of carbon bisulfid. Submersion Method. Submersion is a cheaper and more effective method of controlling the phylloxera, but is necessarily applicable to but few locations, and even where most successful is gradually giving way to the more satis- factory use of resistant vines. Its chief use is to preserve vineyards which are already in bearing, and it may be of use temporarily in some locations in California. In submersion the vineyard must be continu- ously covered with at least six inches of water, as the object is to drown the insects, that is, to kill them by depriving them of air. If the sur- face becomes exposed even for a brief period, air will be absorbed and the insects given a new lease of life. In very porous soils submersion is impracticable on account of the large amount of water required, and ineffective for the reason that the rapid passage of the water carries sufficient air into the soil to keep the insects alive. Submersion is most effective in destroying the insects when they are in their most active condition, that is, in summer. At this time, unfortunately, the vine is also most sensitive to injury. The most favorable time, then, for submersion is as soon as the vines have ceased active growth and before the phylloxera have entered their hibernating or dormant con- dition. This in most parts of California will be some time in Novem- ber. At this period the flooding need last but a week or ten days; a month later, two or three weeks; while during the remainder of the winter little good results unless the submersion is prolonged for thirty- BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 107 five or forty days, and indeed in some soils of the extreme south of France two months has been found necessary. As the insect is most susceptible in midsummer, it was at one time thought that a copious irrigation at that time sufficient to destroy most of the insects without injuring the vines could be effected. At present a flooding in July for not exceeding forty-eight hours is practiced in a few places, but only to supplement winter flooding, or the injection of bisulfid. The insecti- cidal value of the short submersion which the vines will withstand at this time seems to be very slight. Its main value seems to be in prompting a vigorous growth of new rootlets to replace those that have been injured. Planting in Sand Method. Though no thoroughly satisfactory explanation has been given, the fact is established that in certain very sandy soils vines are uninjured by phylloxera. All sandy soils are unfavorable to the increase of the insect, and vines planted in them die more slowly than in others; but for complete immunity the soil must contain at least sixty per cent of siliceous sand. The looser and more fine-grained the sand, the more resistance it offers to the insect. Sands containing notable quantities of clay, all those in fact which have a tendency to form lumps or " cake," offer less resistance. Resistant Vines. The most satisfactory method of combating phylloxera is the use of resistant vines, because it is applicable to all conditions and is the most economical in the end. A resistant vine is one which is capable of keeping alive and growing even when phylloxera are living upon its roots. Its resistance depends on two facts: 1st, that the insects do not increase so rapidly on its roots; and, 2d, that the swellings of diseased tissue caused by the punctures of the insects do not extend deeper than the bark of the rootlets and are sloughed off every year, leaving the roots as healthy as before. The wild vines of the Mississippi valley states have evolved in company with the phylloxera, and it is naturally among these that we find the most resistant forms. No vine is per- fectly immune in the sense that phylloxera will not attack it at all; but on the most resistant the damage is so slight as to be impercep- tible. The European vine ( Vitis vinifera L.) is the most susceptible of all, and all the grapes cultivated in California, with a few unimportant exceptions, belong to this species. Between these two extremes we find all degrees of resistance, which is expressed by a series of numbers ranging from 20, indicating the highest possible resistance, to 0, indi- cating the utmost susceptibility. The following table shows the resist- 108 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. ance (according to Viala and Ravaz and other authorities) of some of the best known species and varieties: Comparative Resistance to Phylloxera. SPECIES WILD VINES. CULTIVATED VARIETIES AND HYBRIDS. Vitis rotundif olia 19 Vitis vulpina (Riparia) 18 Vitis rupestris 18 Vitis Berlandieri 17 Vitis sestivalis 16 Vitis labrusca 5 Vitis californica 4 Vitis vinifera . Gloire de Montpellier (Riparia) .... 18 Riparia X Rupestris 3309 18 Rupestris Martin 18 Rupestris St. George 16 Riparia X Solonis 1616 16 Solonis 14 Lenoir 12 Isabella 5 The degree of resistance necessary for the production of good crops varies with the character of the soil. The resistance expressed by the numbers 16 to 20 is sufficient for all soils. A resistance of 14 or 15 is sufficient in sandy and moist, rich soils, where the vine can readily replace the rootlets as fast as they are destroyed. Fairly successful vineyards have been established with vines having a resistance of less than 14, but as the vines become old the lack of resistance is generally shown by a weakening of the vine and a falling off of the crop. Many vineyards in the south, of France grafted on Lenoir which formerly bore well, have now to be treated with injections of bisulfid of carbon. For the above reason it is advisable to reject all vines with a resistance of 13 or under, especially as vines with greater resistance can now be obtained for practically all conditions. Resistant vines are of two kinds: (a) Those which are grown for the grapes they produce, and (b) Those which are useful only as stocks on which to graft the non-resistant varieties. The former are called "Direct producers" and the latter "Resistant stocks." (a) Direct Producers. When the phylloxera commenced to destroy the vineyards of Europe, the natural attempt was made to replace them with the varieties of vines which had proved successful in the United States, where the insect was endemic. These varieties, however, all proved unsatisfactory. Some, like the Concord and Catawba, were insufficiently resistant, and although they could be grown where the severe cold of winter impeded the prolificness of the phylloxera, they quickly succumbed in the milder grape-growing sections of Europe.* Most of them were poor bearers compared with the prolific European vines, and finally the character of their fruit differed so widely from * In California these and other Labrusca varieties and hybrids resist very little longer than Vinifera vines. BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 109 what Europeans were accustomed to, that there was little sale for the fruit, and the wine could compete with only the very poorest quality of Vinifera wines, and brought a very inferior price. A few of the varieties introduced during that first period are still grown to a limited extent in France, chiefly the Othello and the Lenoir. They are being gradually abandoned, however, as their crops are unsatisfactory, and in many localities can be maintained only by the aid of injections of bisulfid. For some years the search for a suitable producer was almost abandoned by practical men, the use of resistant stocks having been so fully successful. Lately, however, renewed efforts have been made and several new direct producers are being advocated and planted to some extent. The merit of these new varieties, however, is chiefly their resistance to Peronospora and black rot. Phylloxera resistance is con- sidered of much less importance by their most ardent advocates, and indeed the advice is generally given to graft some of the best of these direct producers upon phylloxera-resistant stock. (b) Resistant Stocks. Though high resistance to phylloxera is essen- tial in a grafting stock, there are other characteristics equally necessary. The Rotundifolia (Scuppernong), which has the highest resistance of any vine, is useless as a stock on account of the impossibility of grafting it with any Vinifera variety. This is due to a lack of affinity, which means a lack of similarity in structure and composition between the tissues of the stock and those of the scion. This lack, in extreme cases, results in an imperfect and temporary union, but when not excessive, only in a slight decrease of vigor. The affinity is not perfect between Vinifera varieties and any resistant stock, but in the case of Riparia and Rupestris is generally sufficient to insure permanence to the union, and the slight decrease of vigor consequent often results in an increase of fruitfulness. It is for this reason that certain varieties when grafted on resistant stocks, especially on Riparia, often bear larger crops than when grown on their own roots. Not all varieties of Vinifera have the same affinity for the same stock. For this reason it is desirable to be cautious about making new or untried grafting combinations on a large scale. Some varieties, such as Carignan, Petite Sirah, Clairette, and Cabernet Sauvignon, do excellently on all stocks; while others, such as Mondeuse and Gamay, do not make a very good union with any of the thoroughly resistant stocks. The Petit Bouschet and Cinsaut make very poor unions with any variety of Riparia, but do fairly well on Rupestris St. George. The Pinot Noir makes a vigorous growth upon Rupestris St. George, but bears much more prolificacy upon Riparia Gloire; while the Mataro does not bear on Rupestris St. George and makes poor unions with Riparia Gloire.* * Reconstitution du Vignoble, par. P. Gervais. 1900. 110 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Selection. A very serious defect of many resistant stocks is a slender habit of growth. This is true of most of the vines found growing wild, and cuttings from such vines make poor grafting stock for the stout Viuifera varieties, which will produce a trunk four inches in diameter while the stock is growing only two inches. This is particularly true of the wild Riparias. For this reason great care has been exercised in selecting the stronger-growing vines, and at present we have selected Riparia varieties which almost equal Vinifera in the stoutness of their trunks. The best of these are the Riparia Gloire de Montpellier and Riparia Grande Glabre the first of which has given the best results in California. Adaptation. The European vine is remarkable among cultivated plants for the wide range of soils in which it will succeed. We find vineyards producing satisfactory crops on the lightest sands and on the heaviest clays, on the dry hilltops and in the low, moist plains. This is not the case with resistant stocks. Some, such as the Rupestris vari- eties, are suited to the driest soils; others, like the Riparia varieties, grow well only in rich, moist soils. The question of adaptation, then, of resistant stocks to various soils is of the greatest importance if we are to obtain the best results. After rejecting all unselected and unnamed varieties, such as the ordinary Rupestris and Riparia, which have caused so much disap- pointment and loss on account of their poor growth, and all insuffi- ciently resistant varieties, such as Lenoir, which have succeeded only in the richest soils, our choice of a resistant for a particular soil, climate, and scion must depend on its qualifications as regards affinity and adaptation. After testing thousands of varieties and hybrids originated in Europe and America, a few have been selected as the best for practical pur- poses. In France a fairly good resistant stock has been found for nearly every soil. In California little systematic work has been done in this respect, and we still have the intricate problems of adaptation to solve for most localities. We can, however, profit to some extent by the experience of Europe, and some of the best varieties have been partially tested here and give great promise. Disinfection of Cuttings. The most effective method of treating cuttings suspected of being infested with phylloxera is to expose them to the fumes of bisulfid of carbon. The treatment with liquid insecticides is not nearly so reliable, as Professor Hilgard pointed out many years ago, on account of the difficulty of wetting the buds of many varieties, owing to their protect- ive covering of woolly hairs. BULLETIN 192. INSECTS INJURIOUS TO THE VINE. Ill The method of using the bisulfid is as follows: Place the cuttings in a barrel, vat, or box made tight by means of a thick coat' of paint, or of paper pasted on the inside. On top of the cuttings place a saucer or other shallow dish, and into this pour the bisulfid of carbon. An ordi- nary saucer will hold enough for a box three feet cube or a two-hun- dred-gallon vat. For larger receptacles it is better to use two or more saucers. Deeper vessels will not do, as the saturation is not sufficiently rapid. After pouring the bisulfid into the saucer, cover the box with an oiled canvas sheet or other tight-fitting cover, and allow to stand for from forty-five to ninety minutes. At the end of this time there should be a little of the bisulfid left. If it has all evaporated this is proof that insufficient was used. No flame lights should be used, as the liquid burns easily and the fumes form an explosive mixture with the air. Care should be taken not to spill any of the liquid on the cut- tings, as it may kill them. It is advisable to cut off about half an inch of the lower end of the treated cuttings before planting, as the vapor injures the open pith. Besides disinfecting the cuttings in this way, all the packing material in which they come should be burned or, if valu- able, dipped in boiling water. Practically, it is impossible to disinfect rooted cuttings satisfactorily on account of the difficulty of killing all the phylloxera without seriously injuring the vine roots. THE VINE HOPPER. (Typhlocyba comes Say.) The vine hopper (often called incorrectly the vine thrips) is the most widely distributed and most uniformly present of all the grape insects occurring in the State. It occurs in injurious numbers, however, chiefly in the Sacramento and San Joaquin valleys. It is also present in the coast counties, but rarely in sufficient numbers to do much injury. Another larger species (Tettigonia atropunctata) occurs in these local- ities and sometimes does considerable injury in the early part of the season. The principal injury occasioned by this insect is due to the extraction of the plant juices. These are sucked out by means of a sharp beak or proboscis, which is inserted into the plant tissues. The first evidence of injury is a pale spot around the point of puncture. As these spots become more numerous the leaf assumes a variegated appearance, due to these pale spots, which indicates a lack of chlorophyll or green mat- ter. As the injury increases the leaf becomes pale yellow in color, and later dries up and falls to the ground. The leaves first attacked, and those which suffer most throughout the season, are about the crown of 112 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. the vine. In the vines thus infested, all the leaves within a radius of a foot or two from the center of the vine have dried up and many have fallen off by the end of June or July, thus exposing the fruit. This early loss of foliage prevents the berries from maturing properly. The sugar content of the grape is much reduced, and in table varieties the characteristic coloring, which is important, is not attained. In addition, the fruit is badly soiled by the excrement of the hoppers which serves to hold dust and dirt or offers suitable conditions for the growth of fungi and often this covers the leaves so thoroughly as to interfere with respiration. The loss of leaves, or any interference with their normal functions, also prevents the proper ripening of the canes for the next year's wood, and thus the vine may require a year or more to recover from severe cases of hopper injury. This insect is not more than a tenth of an inch long and of a pale yellow color, prettily marked with irregular red markings. They are usually found on the under side of the leaves, and if these are turned over carefully the insects may be seen. They are very readily disturbed, and often emerge from a vine in swarms, so that they are not likely to be mistaken for any other insect pest of the vineyard. Life History. The life history of this insect as it has FIG. 3. The been worked out in this State during the past year is, grape leaf- . hopper. briefly, as follows: Hoppers which have reached full growth on the vine during the fall or late summer remain in the vineyard or vicinity during the winter season. During the colder days they are more or less dormant and will be found hiding under the leaves, or other rubbish in the vineyard, or sheltered in the vegetation along the bordering fences or roadsides. During the warmer days of winter they become fairly active and will be found feeding on whatever vegetation happens to be growing among the vines or in the vicinity. As soon as the vines come into leaf in the spring, they leave their more varied food-plants of winter and attack the vine exclusively. After feeding upon the grape foliage for about a month, egg-laying begins. This in the Lodi section during the past season was about May first. The eggs are laid just beneath the epidermis, on the lower side of the leaf, rarely on the upper surface. They may be distributed any- where over the surface and are most difficult to see unless one is famil- iar with their appearance. We have counted more than seven hundred of these eggs in a single leaf. One hopper will lay, on an average, seventy-five to one hundred eggs, during a period of from one to two months. The eggs from these over-wintering hoppers require about BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 113 twenty days to hatch. Then the young or nymph appears and begins at once to feed upon the leaves. It is a very small creature, white in color, with conspicuous red eyes. After feeding for a few days it molts or sheds its skin. Altogether it molts five times, requiring a period of from seventeen to twenty days before the last molt, when the full-fledged winged hopper is produced! After feeding for a couple of weeks as an adult hopper, pairing begins and a week later another set of eggs is deposited. These require but from eight to twelve days to hatch, a shorter period than the first lot required, probably on account of the higher temperature later in the summer. Thus the life cycles are repeated. Nymphs arising from the eggs laid by the over-wintering hoppers began appearing about the middle of May, and those from the following brood about the middle of July, making two broods during the season. CONTROL MEASURES. Farm Practices. Since the over-wintering hoppers are sheltered in large numbers by the leaves which are blown together in bunches in the vineyard, and other rubbish along the borders, clean culti- vation will help to reduce their numbers. The hoppers depend for food upon what they can obtain in the vineyard or vicinity, and if the weeds and other vegetation are kept down many will starve or be obliged to go elsewhere for food. When the vineyard is plowed in early spring before the vines come into foliage, the hoppers will all leave the vineyard and feed upon the nearest available vegetation, which is usually about the borders. If these borders and roadsides could be kept free and a general movement for clean culture inaugurated in a neighborhood, it might do much to prevent the hoppers from becoming excessive, but because of the possibility of extensive migrations in the spring the work of any individual grower might be of little avail, though such migrations did not occur at Lodi the present season and individual work would undoubtedly have been useful. The Hopper Cage. So far as the work has progressed this year the most satisfactory method of control is in the use of a hopper cage to be used in the early spring when the young shoots of the vine are about four or five inches long. This is to be supplemented, if necessary, by spraying for the first brood of nymphs early in June. The hopper cage (Fig. 4) consists of a frame work of laths over which is tacked a double layer of mosquito wire netting or a single 20-mesh wire screen. The bottom consists of a shallow pan or tray made by turning up about an inch of the edges of a sheet of light galvanized iron. One entire side of the cage is left open, and there is a V-shaped opening in the tray at the bottom which allows the cage to be pushed over the 2 BUL. 192 114 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. vine. The base of the V-shaped opening in the* bottom is padded with leather and the vine is bumped and the hoppers jarred oft', at the same time that the cage is being swung into position. The sides of the cage and the tray at the bottom are smeared with crude oil, and the hoppers as they are jarred off are caught in the oil. If there is a breeze blowing the cage can be operated with the open side facing the wind and practically no hoppers will escape. If, how- ever, the day is calm and warm and the hoppers are particularly active FIG. 4. The hopper cage. a curtain can readily be dropped over the open side as the cage is pushed, onto the vine, and it will prevent any from escaping. The V-shaped opening which might allow hoppers to drop to the ground in front of the vine can be covered with canvas, as follows: Take two pieces of canvas about the shape of the opening and a little wider. Double this once on itself and between the two layers sew in pieces of three-fourths inch rubber tubing transversely. These are then firmly tacked on the sides of the opening as shown in the figure. This will allow the cage to be pushed in on the vine and the flexibility of the tubing will bring the canvas immediately into position again. This, with the curtain in front, shuts off all possibility of escape. This device can be used to advantage only when the vines are headed BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 115 some little distance from the ground so that the bottom of the cage can be pushed under them. While it is generally conceded that this is the proper way to prune most vines, there are still some vineyards in the State where the vines have been headed immediately at the ground, and some others have been given this form by frost. For such vines, if the cage is to be used at all, it must be used with no bottom, or, at least, a less complete one than the cage described. This cage should be used in the early spring when the shoots are not more than four or five inches long. At this time all the hoppers will be found on the vines and they have not yet laid any eggs. The cage need not be much larger than the diameter of the vines after pruning. The size of the cage and the opening at the bottom should be made according to the size of the vines to be treated. This cage can be used at comparatively little expense there being practically no cost for materials as the chief outlay is the time of the men employed in handling it. Such a cage can be manipulated by a couple of men, and for small vines, four or five years old or under, it may be handled by only one. Four or five acres can be covered in a day and the oil used can be bought for a trifle. If this cage is conscientiously used it will catch from 85 to 95 per cent of the hoppers, and this, at a time before any eggs have been laid, ought to control the situation for the season. No migrations were observed during the past season until about the middle of July, and if the vines have not already been injured, they will not suffer much loss from an attack at this time or later. Spraying. If for any reason the above method has not been used, or satisfactorily done, the next most successful method is to spray for the first brood of nymphs or young. The time for doing this during the past season at Lodi was about the first of June, but the date will vary with the season and location. The sprays which were found to be satisfactory were the whale-oil soap solution and the resin spray. The materials used in these sprays were one pound of soap or resin to fifteen gallons of water. About one-fourth of a pound of ordinary lye should be used to each pound of resin to make it dissolve thoroughly. An "upper shot" spray should be used, and the best type of nozzle for this is an eddy chamber Vermorel, where the liquid is turned at right angles in the chamber. This style does away with anything to catch among the canes, and such a nozzle may be poked anywhere through the vine without being caught. Thoroughness is most important here, since the spray will kill no more than it hits. The under side of every leaf must be wet with the solution. If this is done by the first of June when the growth is small, it is not an exceedingly difficult task. This spraying is expected to kill 116 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. the nymphs only. It will, of course, kill a few adults, but the number of these will be very small. In addition to the adults which escape, there are eggs at this time which the spray will not prevent from hatching. While this means of control will kill a very satisfactory percentage of the nymphs, many adults will escape, and the eggs will be left to hatch later. The advantage of the cage method is that it is more thorough and effective. The hoppers are attacked at a critical time; i. e., when all adults are in the vineyard; and as they have not commenced to breed or to lay eggs the work is effective in greatly diminishing the numbers of succeeding generations. THE IMPORTED GRAPE-ROOT WORM. (Adoxus vitis Fourcroy.) This pest of the vine has been reported from different parts of the State for a number of years, but until a year or two ago it was unknown as a root feeder. In our literature it has / commonly gone by the name of flea beetle, and probably most I, growers know it by that name. It is not, however, a flea beetle at all, since it neither jumps as indicated by the name, nor is its life history similar to that of a flea beetle. It was called by Matthew Cooke, in his book entitled "Inju- rious Insects of the Orchard and Vine- yard," the " Imported Grape Flea Beetle." Since, however, it is a root beetle rather than a flea beetle and is probably an imported insect, and in its life history is almost identical with the grape-root worm of the Eastern States, we propose giving it the common name of Imported Grape-Root Worm. FIG. 5. Adult of the grape-root worm. BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 117 This insect has done considerable damage in this State within the past two or three years, and promises to be a serious enemy of the vine- yardists unless held in check. The grape-root worm of the Eastern States, identical in all important respects with this one, is one of the most serious pests the grape-grower in that region has to fight. The insect injures both the roots and the growing parts of the vine above ground. It is a small beetle, about one-fifth of an inch long, and either black or brown in color. There is no mistaking its identity from FIG. 6. Leaf eaten by root beetle. the way it eats out chain-like strips from the leaf, or gouges out similar strips on the shoots and other growing parts. Life History. The adult beetle appears in May, having emerged from the ground where it has been since the previous year, and where it has passed through the larval and pupal stages. It begins at once to feed upon the leaves, eating out narrow slits about one-twentieth of an inch wide and from one-fourth to three-fourths of an inch long. It attacks the shoots, petioles, pedicels, and to a less extent the berry itself in the same way. After feeding for a couple of weeks, egg-laying begins. The eggs are deposited on the inner bark, or in crevices, usually beneath two or three layers of the old bark. They are laid in clusters of from four or 118 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. five to twenty-five or thirty. Hatching occurs in from eight to twelve days, when the young larva appears and crawls, or possibly drops, to the ground and makes its way to the roots. After having burrowed its way through the ground to the roots it begins feeding, probably mostly on the smaller roots at first, later attacking the larger ones and eat- ing out strips of the bark. This feeding continues until winter, when the larva becomes dormant, finally changing to the pupa in the following spring. Pupation took place this year during the last of April, and continued well into June. The first beetles emerged about the first of May. The most serious injury to the vine is due to the work of the larvae FIG. 7. Imported grape-root worm. ,1 ,1 n i on the roots, the small roots being eaten off entirely, thus preventing the plant foods, taken up directly by the root hairs, from reaching the growing parts of the vine. The larger roots are injured by having strips of the bark eaten off, in bad cases of injury scarcely any of the bark being left. Vines thus affected show a stunted condition, the canes failing to attain a normal growth, and in severe cases the vines may be killed outright. Con trnl Measures. Since the insect comes to the surface and feeds upon the leaves and other growing parts of the vine an opportunity is offered for fighting it in this stage. The beetles are very readily jarred from the vine and may be captured if something is placed under the vines in which they can be caught. The hopper cage, described on page 114, checked the development of the beetles in a vineyard near Lodi during the past season. This means has the advantage of capturing the hoppers also, which are more than likely to be present, at the same time. The fact that the beetles keep emerging from the ground for a month or so may make more than one operation necessary. Fortunately, however, the beetles are usually confined to a limited area of the vineyard, so that it is not necessary to go over a large area. When the beetles alone are to be caught, simply the tray on the bottom of the cage can be used. Handles may be attached directly to the tray for convenience in manipulating. These beetles may also be fairly well controlled by an arsenical spray. They are rather resistant to poisons and a strong dose must be used. We obtained fairly satisfactory results by using lead arsenate in the ratio of five pounds to fifty gallons of water. Paris green may BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 119 be used and the ratio of at least one pound to one hundred gallons of water is required. This spraying should be done as soon as the first beetles make their appearance in the spring. Since the pupae are within four to eight inches of the surface much good can be done by thoroughly stirring the ground within a radius of two or three feet about the vine for a depth of six inches or more. If this can be done at the proper time when they are in the pupal stage it will no doubt destroy many. It has been suggested and some experiments seem to prove that if the land is left uncultivated about the base of the vine, the beetles will be unable to break through the crust at the surface. We have not had opportunity to demonstrate this point. If successful it must depend largely upon a type of soil that will form a hard, impenetrable layer at the surface. HAWK MOTH LARVAE. These larvae are occasionally met with over large areas every year in California, and in certain restricted areas they sometimes become exceedingly abundant and may completely defoliate a vineyard. The worst case that has come to our notice this ye^ir was on a vineyard belonging to the California Wine Association near Reedley. FIG. 8. Showing one vine in a 75-acre vineyard defoliated by Hawk Moth larvae. 120 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Here seventy-five acres of vines were completely stripped of their foliage and scarcely an entire leaf was left on the area. As many as one hundred and fifty full-grown larvae were counted on a single vine. In this case the owners were not aware of the extent of the danger until the worms had become nearly full grown, and most of the damage done. At this time, however a gang of about two hundred men was set to work picking them off the vines, and worms were carried away by the cartloads 'and burned. The species concerned here was the Achemon Sphinx (Philampeles achemon Drury), which is the most com- mon species attacking the grapevine in the State. These caterpillars may be found on the vines late in May, and during the larger part of June. The larva? are green in color, like the leaf, and are therefore not readily distinguishable when they are small. They soon increase in size, however, and their work on the leaves becomes noticeable. While small, these larvae may be distin- guished by a large horn on the posterior end of the body, but this is lost during a molt before they are quite full grown. Life History. These insects hibernate in the pupa or chrysalis stage, and while in the ground may be distinguished as large cylindrical objects of a dark brown color (Fig. 10). About the middle of May or thereabouts they emerge from these chrysalids in the ground as large and handsome moths (Fig. 11). These are the common moths that poise over flowers at dusk. They are particularly attracted by petunias, and it has been suggested that they might be captured in large numbers about these flowers. The eggs are laid on the vine, and the larvae, upon hatching, begin immediately to feed upon the grape foliage. Since they are voracious feeders and grow to a very large size, three inches long or more, they consume an enormous quantity of leaves. This year most of the larvae were mature by the twentieth of June. When mature they repair to the ground, where they pupate. In the vineyard already mentioned, there appeared a second brood of caterpillars during the middle of July. None of these reached their full growth, dying from some unknown cause while they were but an inch and a half long. They FIG. 9. Hawk Moth larva. (Philampeles achemon Drury.) BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 121 had all disappeared when we visited the vineyard on August the first, and according to the owners they simply dried up. It was probably due to a fungous disease which often destroys these cat- erpillars in great numbers. We also found these cater- pillars in the vine- yards about Lodi in June and August, indicating that there are two broods in a season. Control Measures. Where there are but occasional specimens of this insect found in the vineyard, the cheapest and most practical way is to pick them off by hand. Where there are immense num- bers of them, as in the case mentioned at Reedley, hand picking becomes a laborious task. In the latter case a thorough spraying with a strong arsenical spray applied just at the time they are hatching, will check them before' they can do a great deal of harm. If the adult moths are particu- larly attracted by the petunias, as seems to be the case, ' a means of capturing them in this stage may be found in poisoning the flowers thoroughly with some soluble poison or by catching them in traps. The effectiveness of these methods will FIG. 10. Chrysalids of a Hawk Moth (Philampeles achemon Drury). FIG. 11. Hawk moth (Philampeles achemon Drury). 122 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. depend upon whether many of the eggs are deposited before they fly about much. While numbers of moths may be caught in this way, it is doubtful if it will ever prove of very great practical value. GRASSHOPPERS. These insects do a great deal of injury to vines every year in some parts of the State. This year they have been abundant everywhere and considerable damage has resulted.* In a vineyard twelve miles east of Fresno forty or fifty acres of vines were completely defoliated. These insects are generally most troublesome in new vineyard sections or localities surrounded by large areas of uncultivated land. FIG. 12. Vineyard defoliated by grasshoppers. Life History, The eggs of the grasshoppers are laid in the ground in the late summer or fall, and a decided preference is shown for uncul- tivated land. These eggs are laid in capsules containing a large num- ber, and are protected by a frothy or gummy substance which prevents them from being affected by unusual weather conditions. The eggs remain in the ground during the winter and hatch 'the folio wing spring. The young grasshopper is similar in appearance to the adult, except that the wings are lacking, but these are gradually acquired with molt- ing. There is usually but a single generation, though in some parts of the State there are probably two. BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 123 FIG. 13. Valley grasshopper ((Edaleonotus enigma). Control Measures. Grass- hoppers may be controlled by poisoned bait, by spray- ing heavily a few rows along the border of a field, by the hopper dozer, by burning waste feeding areas, and by the introduction of turkeys. Various combinations of two or more of these measures may be used to fit particular cases. Of the methods used to protect vineyards, poisoned bait is probably the most common. This consists of bran and molasses or other sweet substance poisoned with arsenic and distributed in handfuls about the vine. The proportions are as follows: forty pounds of bran, two gal- lons of cheap molasses, and five pounds of arsenic. Cheap glycerine may be used to pre- vent the mixture from drying. If the grasshoppers are enter- ing in well-defined swarms and caught on the first few rows they may be killed by heavily poisoning a few rows on the side at which they are entering. Some growers find turkeys to be the most successful destroyers, and if the hoppers are not too abundant, this method is probably as good as any, particularly at a time when the hoppers are still small. FIG. 14. Differential grasshopper (Melanoplus differentialis). Young. FIG. 15. Differential grasshopper (Menanoplus differentialis). Adult. 124 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Those who have been most successful with turkeys go about using them in a systematic way. They turn in a band of them early in the morning and let them feed for a couple of hours, then drive them into a cool barn where they remain through the heat of the day. In the evening they are again turned into the vineyard for two or three hours and again confined in an inclosure, so that they obtain a straight grass- hopper diet supplemented by gravel, to which they have access while not in the vineyard. When vineyards adjoin, or are near, large uncultivated tracts, where the grasshoppers hatch out in large numbers, it is best to look beyond the vineyard in planning the control. This may mean more or less organized effort in burning off or plowing such uncultivated lands. For a full account of this and other methods of grasshopper control the reader is referred to Bulletins Nos. 142 and 170 of this Station. CUT WORMS AND ARMY WORMS. These are the larvae of Noctuid moths, which often become abundant over limited areas and do much damage to vines. Cut worms and Army worms are terms applied to the same insects in California. In ordinary years they are not present in sufficient numbers to cause much concern, and in such years they are known simply as cut worms. When all conditions are favorable, however, certain species develop in enormous numbers and having exhausted the food supply where they breed, they begin to migrate or march, commonly in a definite direction, as an army in search of new food. When they thus appear in such large numbers and take on the migrating habit they are called army worms. Some of the caterpillars have the habit of climbing up vines and trees and eating off the buds in the early spring. These are called climbing cut worms. Others remain at or near the surface of the ground and feed by cutting off the plants at this point. They are more commonly found in the grass lands, but very frequently attack culti- FIG. 16. Army worm (Heliophila uni- puncta). The species that was abundant at Lodi this year. BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 125 vated crops, particularly on land that was in grass the previous year. It is the two former the climbing cut worms and army worms that chiefly concern growers of vines. The climbing cut worms appear in the early spring and eat off the expanding buds. They also feed upon the young leaves as they appear, but an early attack on the swelling buds is when the most serious damage is done, because the removal of the principal bud destroys the fruit and the later buds usually produce sterile shoots. The two commonest species concerned here are Paragrotis meswria Harris and Peridroma margaritosa sauci Hubn. The life history of all the species of this group is much the same, FIG 17. Moths of cut worms. .and they may be discussed together. The majority spend the winter as a partly grown larva. In the spring they again become active and begin to feed after being more or less dormant during the winter. If they are the climbing species they may be found attacking the buds or young leaves of the vine. When they become full-grown larvae they go to the ground, where they change to pupae. After two or three weeks in this stage the adult moth appears. These are usually dark colored (Fig. 17), and because they fly about at night are seldom seen. The eggs are laid mostly on the stems of grasses near the ground. The larvae hatching from these feed at or near the ground, and since they work mostly at night are not readily seen in their concealed situa- tions during the day. There being plenty of vegetation at this season also they do not interfere seriously with the crop. By fall they become 126 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION. partly grown and spend the winter in a more or less dormant condi- tion. There are generally two broods of the worms in California and in some cases probably three. Any one of several species, however, may increase to immense numbers, and they are then called army worms. They appear in large numbers as army worms, generally with the second brood in midsummer. During the past year in the vicinity of Lodi there was a distinct outbreak of army worms appearing simulta- neously in a dozen or more different places. In nearly every case these came from grain fields in which they bred, and because of the large numbers and scarcity of food were forced to migrate, and as a result, a number of vineyards were threatened with defoliation. These grain fields or breeding places become pretty well dried up by August, and furnish very little succulent growth for the voracious army worm. The worms appeared this year during the first week in August. They had been feeding for a week or two in the grain fields, since some were nearly full grown, but had not been observed to migrate until the date mentioned. In one of these grain fields a contagious bacterial disease killed them off by the thousands, and very effectively checked their progress. Portions of a number of young vineyards were defoliated before their presence was realized. The species concerned here was the true army worm of the Eastern States, which bears the scientific name of Heliophila unipuncta. In bearing vineyards, besides eating off the leaves, these worms have the pernicious habit of cutting off the stems of the clusters of fruit, which drop to the ground and dry up. In a portion of a bearing vineyard near Lodi, where these pests were present, this unripe fruit was picked up, while still fresh, by the basketfuls and made into jelly. These caterpillars are mostly dull-colored worms from one to two inches long, with longitudinal strips of black, gray and yellow or red- dish brown. There is considerable variation in color in the same species, some being much darker in color. Generally the midsummer brood from which the army worms arise are darker colored than the spring brood. The one present in Lodi and vicinity this year (see Fig. 16) had a broad black velvety stripe on the dorsal side. Below this was a stripe of whitish yellow about one half the width of the former, with its center made up of broken wavy lines. Below this was another narrow stripe of black with the spiracles on the lower edge; back and a little above each spiracle was a conspicuous white spot that on first sight would be taken for the spiracles themselves. Below this is another stripe of light brown, and on the ventral surface a general color of cinnamon brown. Control Measures. The cut worm, although belonging to the same group as the army worm, on account of the difference in habits must be controlled in a different way. Since it is those species which acquire BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 127 the climbing habit that attack vines, they require a different manner of treatment from those which feed upon plants at or near the surface. Because they actually devour the buds of the vine, the application of a poison spray ought to be effective. However, since the surface on which there may be poison in the case of buds is so small, one worm may destroy most of the buds on an ordinary-sized vine before the dose eaten will prove fatal. Probably one of the best ways of fighting these is to place poisoned bait around the base of the vine. (For the ingre- dients see under Grasshoppers, page 123.) This will be eaten by the worms in preference to climbing up the vines and destroying the buds. They may also be captured by means of traps. Because of their habit of feeding at night and remaining concealed during the day, pieces of boards may be placed on the ground around the vine and these may be turned over during the day and the worms killed. In case of outbreaks of army worms the most important and success- ful means of fighting them is to keep them out of the vineyards entirely. This can be successfully done if they are discovered in time, or if already in one portion they can be kept from spreading over the rest of the vineyard. They travel in immense numbers in a definite direction, coming generally from an adjoining or nearby grain field. If a furrow is plowed along the side of the vineyard to be protected it will effectively stop their progress. This furrow should be plowed as deep as possible, with the vertical side next to the field to be protected. It can be further trimmed with a spade, preferably cutting under slightly, making a smooth surface, over which few if any, of the worms will make their way. Above this shoulder fine pulverized earth should slope as abruptly upward as possible. If any of the worms succeed in climbing up over the smooth surface made by the spade they will be pretty sure to fall back as they reach this fine loose earth in an attempt to ascend over the projecting shoulder. Postholes should be dug. on the straight edge of the furrow every fifteen or twenty feet. The worms in failing to scale the vertical side of the furrow will crawl along in the bottom and fall into these holes. Here they may be killed by pouring in a little crude oil, or by pouring in a little distillate and dropping in a match, thus burning them, or the holes filled in and others dug. They may also be killed in the furrow by sprinkling them with kerosene or by pouring a strip of crude oil along the furrow. It is most essential in fighting army worms that prompt and vigorous efforts be undertaken immediately, since a day's delay may mean con- siderable loss and more difficulty in handling the situation. Once they are in the vineyard the vines infested should be heavily sprayed with lead arsenate at the rate of five pounds to fifty gallons of water, or with paris green in the proportion of one pound to seventy-five or one hundred gallons of water. In addition to this the furrow should be 128 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. plowed, as already described, beyond the infested portion to check their further spread. If these measures are undertaken promptly, what might be a serious loss can be averted. FLEA BEETLES. (Haltica sps.) These beetles have generally been confused with the root beetle already discussed in this bulletin. In these beetles the thighs of the hind legs are enlarged, thus enabling the insect to jump much in the same way as the flea; hence the name. They have frequently been reported as doing damage in the State, but during the past season we have not learned of any important injury done by them. Two or three specimens were taken near Lodi, and while no particular effort was made to collect them, this was all we obtained during the season. Certainly there were no large numbers of these beetles in the sections where our work was carried on this past year. Several growers reported that the flea beetle was doing considerable damage, but upon investi- gation these were found to be the root beetle. They are said to be particularly abundant in the Sonoma Valley, but we did not have the opportunity of visiting the valley during the present season. There are about a dozen species of the genus Haltica occurring in this State, probably the commonest occurring on the vine being the species bimar- ginata. This species is not confined to the grape alone, and during the past year it was exceedingly abundant in many places over the State "on the alder. The grape flea beetle of the Eastern States (Haltica chalybia) is not known to occur here. The flea beetle on the grape is commonly of a bluish color, about one- fifth of an inch in length, and is capable of jumping, while the root beetle is either black or brown in color and has no power to jump. The injuries of these two beetles are also readily distinguishable. The flea beetle eats out irregular holes, which may differ much in size and shape, while the root beetle eats out narrow strips of very uniform size and shape. They also present entirely different life histories. Life History. The flea beetle passes the winter among leaves or in other situations affording some protection to the adult beetle, and emerges in the early spring and feeds upon the buds of the vine. These may be entirely eaten away or the centers gouged out, thus destroying the buds. After feeding for some time they begin depositing their eggs, generally in the cracks in the bark or at the base of the buds. The larvae, after hatching out, attack the leaves and eat out holes, as already indicated. They continue to feed as larvse for three or four BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 129 weeks, when they drop to the ground, make a little cell just beneath the surface, and change to pupae. The beetles emerge a week or two later and these feed upon the leaves. There are probably two genera- tions of the insect each year. Those we obtained were taken as adult beetles in June, which were from eggs laid in the early spring, but whether these remain until winter and hibernate, or again lay eggs, was not determined. Control Measures. Since this insect feeds upon the foliage both as larva and adult, it may be controlled by means of a poison spray, either paris green or lead arsenate. The beetles are also easily jarred from the vines and the method described for capturing the root beetle can be used here. THE GRAPE-LEAF FOLDER. ( Desmia funeralis Huber. ) This insect occurs in considerable numbers in some sections of the State every year, but the total injury is not usually very great. During the past season the worst attack that came to our notice was in a vine- yard near Reedley, where seventy-five .or one hundred acres of vines had a large number of their leaves rolled. On some vines nearly every leaf was found to be rolled and harboring the larvae of this insect. Occasional specimens were also found near Lodi, but they were not numerous enough to do any important injury. They may be easily detected in a vineyard by the characteristic rolling of the leaves. One edge is rolled up rather tightly to about half way across the leaf, making a tube less than the diameter of a lead pencil, in which the larva lives. The leaf is always rolled on the under side. The insects feed by eating off the free edge of the leaf in the interior of the roll, so that they are always protected by the outer layers of the rolled portion. The insect hibernates as a chrysalis, appearing and laying eggs upon the vine in the spring. The larvae of the first brood appear about the first of June. By the twentieth of June at Reedley this year the Iarva3 had all changed to pupae. The larva is a greenish- white caterpillar, about an inch long when full grown. They wriggle out of their nests very vigorously when disturbed and drop to the ground. *Larvae were taken at Lodi in June and August, indicating that there are at least two broods in a season. * The head and prothoracic shield are light brown in color. On the mesothoracic segment are two pale-brown spots or rings, and beyond these laterally are two larger and darker crescent-shaped spots. There is also a pale spot on the same segment more ventrally and a little forward. On the preceding segment are two large irregular pale- brown spots and one small round spot, also of pale brown. On the penultimate segment there are two dark crescent-shaped spots situated dorsally. 3 BUL. 192 BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 131 This insect occurs, apparently, throughout the United States. It is very common in the Eastern and Middle Western States, but there is FIG. 19. Larva of grape leaf-roller. a striking difference in habits between the insect there and what is considered the same species here. In the East, the leaf is simply folded FIG. 20. Moth of grape leaf-roller, enlarged. over on the upper surface and the edges sewed down by strands of silk. There the larva feeds by eating off the upper surface of the leaf, thus skeletonizing it. Here the leaf is very distinctly rolled and instead of 132 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. eating off the upper surface it feeds on the free edge. According to its habits in this State, leaf-roller would be a more appropriate name than leaf-folder. Specimens of the moth sent to the Bureau of Entomology at Washington, D. C., were identified by Dr. Dyar as Desmia funeralis Huber the same species that occurs in the Eastern States. The moth is nearly an inch across the expanded wings, and is black with white markings. There are two white spots on each wing, those on the posterior wings being larger, and in some specimens fusing into a single large spot. There are also two white bands across the abdomen, one about the center and one near the tip. The wings are also bordered with a fringe of white, and the tarsi and apical half of the antennae are white. Control Measure. The only control measure which is likely to prove effective is to spray with an arsenical before the rolling of the leaf is commenced, so that they may be obliged to eat the poison, even though they are within the rolled portion. If they are not too abundant, hand picking or simply crushing the folded portion of the leaves will be the most practical. LEAF CHAFERS. Under this head come the rose chafer, and other allied species, which often attack the leaves of the grapevine. The true rose chafer, which often does much injury to vines in the Eastern States, as far as we are aware, does not occur in California. A species which was very abundant in the neighborhood of Florin during the past season was Serica mixta Lee. This insect was not restricted in its feeding, however, to the vine, but attacked a great variety of plants. Hoplia sackonii has also been taken in large num- bers on vines at Fresno. The life history of the rose chafer has been carefully studied, and the life history of these allied species may be much the same. The younger stages of these insects are passed in the ground, where the larvae feed upon the roots of plants, preferably grasses. They are full grown by fall and in the spring ascend toward the surface, where they change to pupae. Two or three weeks later they emerge from the ground as adult beetles and attack the grape and other plants. A sandy soil is especially adapted for their underground habits. After feeding as adult beetles for two or three weeks they deposit their eggs in the ground and from these the next generation of larvae emerge and feed upon the roots until fall. Control Measure. These insects are rather difficult to control, but a liberal dose of poison will check them if they are not present in great BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 133 swarms, as they sometimes occur. The jarring method as described for the root beetle will also prove valuable. Since these insects feed in the larval state upon the roots of grasses growing along the roadsides or fences or irrigation ditches, much can be done to prevent an outbreak by keeping euch places free from vegetation. WIRE WORMS. These are long cylindrical worms with a dark brown leathery covering resembling somewhat a piece of rusty wire. They live for a year or more in the ground, feeding upon the roots of plants. They feed upon a variety of plants and are not restricted to grape roots alone. We have taken as many as fourteen of these worms from around the roots of a vine from a foot and a foot and a half from the surface. During the growing season of the vine when the vineyard is free from vegetation these wire worms must feed to a considerable extent upon the roots of the vine. The adult is the well- known click or snapping beetle, the one most commonly met with being about one-half an inch long, slender, and of a dark brown or black color. We have seen immense swarms of these click beetles in a vineyard near Hanford, and when they occur in such large .numbers they probably do considerable injury to the vine as root feeders. When young vines are planted in soil which has previously been in hay or pasture the wire worms may attack the bark just below the sur- face and kill the vine by girdling it. Rupestris St. George seems particularly susceptible to this form of attack. The vines may be saved if the wire worms congregated around the collar of the vine one or two inches below the surface are collected by hand in time. Treatment. We know of no generally satisfac- tory remedy for these insects. Turning up the soil is recommended for the same insect in the FIG. 22. Young vine gir- dled by wire worms. UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. East, especially in the fall or winter, but such an operation is likely to prove of little value in our climate here. Besides, most of those found around the vines were below the reach of any plow. Clean culture in the vineyard will do as much as anything, since ordinarily they feed upon the roots of grasses and other plants at a comparatively short distance from the surface. ERINOSE.* Erinose is a disease of the vine characterized by swellings on the upper surface of the leaves, and corresponding depressions on the lower surface. These swell- ings, when numerous, cause considerable deformation of the leaves, but not the change of color to yellow or brown which is characteristic of most fungous diseases. Even very badly affected leaves retain almost their normal green color on the upper sur- face until late in the season. The depressions on the under side are coated with a thick felt-like covering, which, at first pure white, gradually turns rusty and finally becomes dark brown. Generally, the swellings and corresponding depressions are isolated and few in num- ber on the affected leaves, but in severe cases they are numerous enough to become confluent and the whole lower surface is then completely hidden by the felt-like covering. Occasionally, indeed, the felt-like material extends to the upper surface in narrow strips bordering the veins, and may even be found on the petioles and flower clusters. Most of the specimens received at the laboratory are sent under the impression that they are attacked by a fungus, and, in fact, the coating has a strong superficial resemblance to some fungous growths. A micro- scopic examination shows, however, that it consists of a mass of hyper- trophied hairs or abnormal outgrowths of the epidermal cells of the leaf. T.hey are larger, more abundant, and more persistent than the * Revised from Bulletin No. 136, by F. T. Bioletti and E. H. Twight. FIG. 23. Vine leaf affected with Erinose upper surface. BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 135 normal leaf-hairs of the leaf, and differ also in being often branched and usually unicellular. This abnormal growth, in common with similar growths found on other pl'ants, is called an erineum, from a Greek word meaning woolly. This is the derivation of the word erinose, which means woolly disease a very appropriate name. The erinea of leaves were formerly supposed to be of fungous origin, but are now known to be due to the attacks of minute mites. The feeding of these mites exert a stimulating effect upon the epidermal cells of the leaf, which causes them to grow out into the abnormal hair-like processes already described. The mite causing erinose of the vine is known as Eriophyes vitis, and is related to the mites causing a similar disease of the walnut and the leaf blister of the pear, both of which are very common in California. The Eriophyes vitis is not a true insect, but a mite or acarid belong- ing to the class of Arachnida to which belong also spiders, scorpions, ticks, and our common red spider so destructive to fruit trees. These mites are extremely minute, and only a practiced eye can perceive them among the tangled mass of erineum on the leaf, by the aid of an ordinary hand magnifier, and then only with great difficulty. Amount of Injury. Erinose was formerly considered to be a very serious disease of the vine, owing to the fact that its effects were con- fused with those of the powdery mildew. It is only in very exceptional cases that it is, alone, capable of doing serious injury to the vine or its crop. When accompanying oidium or drought it may, however, per- ceptibly increase the damage due to these causes. When very abundant it may seriously interfere with the growth of young vines, but accord- ing to Mayet, never damages old vines, except by interfering slightly with the ripening of the canes, or at most causing an almost impercep- tible diminution of crop. All varieties of vines are not equally attacked. According to Ravaz, certain American species such as Berlandieri, Mustang, Cinerea, Cordifolia, and Scuppernong are immune. All vari- eties of Vinifera are susceptible, but not equally. Of varieties culti- vated in California, Sauvignon, Sirah, Marsanne, and Gamay Teinturier are said by Ravaz to be little subject to attack; while Aramon, Cinsaut, and Frontignan (Small Muscatel) are very susceptible. The worst cases so far observed in California have been on Flame Tokay and Mission, but it has been found also on other varieties, among them Zinfandel and Muscat. Distribution in California. The first specimens of erinose received by the Experiment Station we-re sent from Windsor, Sonoma County, in 1896. The next year affected leaves were received from Healdsburg and Dry Creek, in the same county. All these cases were upon Mission vines. Since then specimens of the disease have been received from nearly every grape-growing county of the State. 336 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION. Methods of Treatment. Since sulfuring the vines for the treatment of oidium has become general in France, there has been little trouble with erinose. The mite seems as sensitive to the fumes of sulfur as the red spider, and several sulfurings during the late spring and early summer are recommended for the control of the mite. The only vineyards which have been found badly affected in California are those in which little or no sulfuring has been done, or those where the growth of foliage has been so luxuriant as to prevent the evaporation of the sulfur by the sun. In the latter cases the vines are so strong that they practically receive no harm from the disease. Tests made on Tokay vines indicate that the erinose can be easily and readily controlled at any stage in California by sulfuring. In severe cases a winter treatment of the vine stumps is practiced in France. This treatment consists in pouring about one quart of boiling water over the stump. For very large stumps a somewhat greater amount of water is used, and for smaller, vines a proportionate amount. This method is said to be very efficacious, and with the portable boiler constructed for the purpose two men can treat from fifteen hundred to two thousand vines per day. Cuttings taken from affected vines for the purpose of rooting or grafting may be thoroughly disinfected by placing them in hot water (122 F.) for ten minutes. If this is done carefully all the mites and their eggs will be destroyed without injury to the cuttings. NEMATODE ROOT GALL. (Heterodera radicola (Greef) Mull.) Nematodes are not insects, nor are they very closely related to insects. They belong to the class of animals known as Vermes or true worms. The common earthworm is the best known example of the class, although it occupies a position in the group higher than that of the nematodes. There are a good many species of nematodes some living in the ground, a good many are parasites on animals, and a few live parasitically on plants. Often in moist soil, rich in humus, such as vegetable gardens, there may be large numbers of very minute whitish transparent worms. These are nematodes, however, that do no notice- able injury to plants, and it is only the parasitic species, of which the subject of this account is an example, that are of any concern to growers of crops. The species of nematode worm that attacks the grapevine in this State according to Dr. Ernst Bessey of the Department of Agricul- ture, who is at present engaged in an investigation of this group is Heterodera radicola (Greef) Mull. This species is widely distributed BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 137 over the world, and attacks a large variety of plants. In the Argentine Republic it is said to be the most destructive disease of the vine occur- ring in that country.* In the United States, outside of greenhouses, nematodes are chiefly injurious in the Southern States and in California. This parasitic species is an exceedingly small wormlike creature about one seventy-fifth of an inch long, and of a transparent whitish color. It has a sharp slender organ on the head that enables it to make its way into the more tender portions of the roots, where it embeds itself in the tissues. Here it develops, and lays the eggs from which succeed- ing generations arise. These may scatter through the soil and attack other portions of the root. By means of this sharp lancelike organ they are able to draw nourishment from the roots. It is not M so much this direct drain on the roots, how- ever, that causes the damage as it is in the decay of the hypertrophied tissue due to the irritation caused by the work of the worms. They make conditions favorable for the attack of wood-rot fungi, which hasten the decay. The roots of vines infested with this worm show numerous swellings, some- what like that due to phylloxera. The nodosities or swellings caused by phyllox- era, however, are most conspicuous and are larger on the smaller roots, while those of nematodes are largest on the larger roots. The swellings are also of firmer consistency than those of phylloxera. The general effect on the vine is not very different from that of the phylloxera. The distribution of the affected vines will, however, gener- ally distinguish the two. Vineyards infested with phylloxera show the characteristic oil-spots, the interior vines being worst affected and grad- ually diminishing in injury toward the periphery of the affected spot. The amount of injury is said to vary with the soil conditions, but the authorities apparently are not agreed, some claiming less injury in light, sandy soil and others the reverse. Moisture is, no doubt, the most important factor in favoring their development. In California this pest seems to be most common on vines in the Fresno section, and, in general, this is a section of sandy soil. Control. No satisfactory remedy has yet been found for controlling parasitic nematodes. In greenhouses the usual procedure is to sterilize the soil, but this, obviously, is not applicable to a vineyard. However, *Boletin del Ministerio de Agricultura, Buenos Ayres, Mayo de 1906. FIG. 24. N. Swellings on the roots of vine caused by the Nematode root gall. M, M. Eggs of the Nematodes found in these galls. 138 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. if the soil is known to be infested, disinfection is sometimes practiced before planting out young vines. This is done by an application of carbon bisulfid to the soil. Trap plants have also been used, these being annuals that are pulled up before the nematodes escape. In time it may be found that resistant stock is the solution of the problem. In the bulletin already referred to it is stated that the Isabella is slightly resistant, while Vitis riparia has shown no nodules after the first year. This fact is interesting as a suggestion that both phylloxera and nematodes may be controlled by the same resistant. BULLETIN 192. INSECTS INJURIOUS TO THE VINE. 139 KEY FOR DETERMINING THE INSECT INJURIES TO THE VINE DESCRIBED IN THIS BULLETIN. Injury to the Leaves. No part of the leaf eaten away, but having pale spots, or being entirely pale yellow, or dried up, those about the crown of the vine, particularly the lower ones, worst affected. Vine hopper, page 111. Leaves with irregular holes eaten out. Flea beetles, page 128; Grass- hoppers, page 122; or Leaf chafers, page 132. Leaves with regular chain-like slits eaten away. Root beetles, page 116. Leaves rolled up from one side. Leaf rollers, page 129. Leaves entirely devoured. Army worms, page 124; Grasshoppers, page 122; Hawk moth larvss, page 119. Leaves with swellings on upper surface, and grayish white to dark, brown felt covering on corresponding depressions on under side. Erinose, page 134. Injury to Petioles and Pedicels. Narrow strips of uniform size eaten away. Root beetle, page 1 16. Injury to the Berry. Narrow strips about one fourth of an inch long gouged out. Root beetle, page 116. Clusters cut off and dropped to ground. Army worm, page 124. Injury to the Roots. Long strips of the bark eaten away. Root beetle, page 116. The smaller rootlets only eaten of!'. Wire worm, page 133. Nodosities or swellings, largest on smaller roots, often at extreme tip, decay of hypertrophied tissue. Phylloxera, page 99. Nodosities or swellings largest on larger roots, two or three times the diameter of those caused by phylloxera, and of firmer consistency, none at extreme tip. Nematodes, page 136. Injury to the Whole Vine. These are the same as under root injury, since injury to the roots affects the vine as a whole. Vines whose canes are checked in growth or completely stunted, and if leaves have chain-like strips eaten out. Root worm, page 116. 140 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Vines in circular spots in vineyard showing stunted growth, those in center of spot worst affected and gradually diminishing outward. Phylloxera, page 99. Vines with symptoms similar to phylloxera, but not in well-defined circular spots, nor with interior ones worst affected. Nematodes, page 136. HOW TO SEND SPECIMENS. Insect specimens should be inclosed in a wooden, tin or strong paste- board box. No provision need be made for air. Accompany specimens with samples of their work. If roots or leaves, wrap in moist news- paper and inclose in tight box to prevent drying. If phylloxera is suspected, place pieces of roots in a firm box that is absolutely tight; .,or otherwise thoroughly seal, to prevent any possibility of escape in the mails. STATION PUBLICATIONS. STATION PUBLICATIONS AVAILABLE FOR DISTRIBUTION. REPORTS. 1896. Report of the Viticultural Work during the seasons 1887-93, with data regarding the Vintages of 1894-95. 1897. Resistant Vines, their Selection, Adaptation, and Grafting. Appendix to Viticultural Report for 1896. 1898. Partial Report of Work of Agricultural Experiment Station for the years 1895-96 and 1896-97. 1900. Report of the Agricultural Experiment Station for the year 1897-98. 1902. Report of the Agricultural Experiment Station for 1898-1901. 1903. Report of the Agricultural Experiment Station for 1901-1903. 1904. Twenty-second Report of the Agricultural Experiment Station for 1903-1904. TECHNICAL BULLETINS ENTOMOLOGICAL SERIES. Vol. 1, No. 1 Wing Veins of Insects. No. 2 Catalogue of the Ephydridae. BULLETINS. Reprint. Endurance of Drought in Soils of the Arid Region. No. 128. Nature, Value and Utilization of Alkali Lands, and Tolerance of Alkali. (Revised and Reprint, 1905.) 133. Tolerance of Alkali by Various Cultures. 140. Lands of the Colorado Delta in Salton Basin, and Supplement. 141. Deciduous Fruits at Paso Robles. 142. Grasshoppers in California. 147. Culture Work of the Substations. 148. Resistant Vines and their Hybrids. 149. California Sugar Industry. 150. The Value of Oak Leaves for Forage. 151. Arsenical Insecticides. 152. Fumigation Dosage. 153. Spraying with Distillates. 154. Sulfur Sprays for Red Spider. 156. Fowl Cholera. 158. California Olive Oil ; its Manufacture. 159. Contribution to the Study of Fermentation. 160. The Hop Aphis. 161. Tuberculosis in Fowls. (Reprint.) 162. Commercial Fertilizers. (Dec. 1, 1904.) 163. Pear Scab. 164. Poultry Feeding and Proprietary Foods. (Reprint.) 165. Asparagus and Asparagus Rust in California. 166. Spraying for Scale Insects. 167. Manufacture of Dry Wines in Hot Countries. 168. Observations on Some Vine Diseases in Sonoma County. 169. Tolerance of the Sugar Beet for Alkali. 170. Studies in Grasshopper Control. 171. Commercial Fertilizers. (June 30, 1905.) 172. Further Experience in Asparagus Rust Control. 173. Commercial Fertilizers. (December, 1905.) 174. A New Wine-Cooling Machine. 175. Tomato Diseases in California. 176. Sugar Beets in the San Joaquin Valley. 177. A New Method of Making Dry Red Wine. 178. Mosquito Control. 179. Commercial Fertilizers. (June, 1906.) 180. Resistant Vineyards. 181. The Selection of Seed- Wheat. 182. Analysis of Paris Green and Lead Arsenate. Proposed Insecticide Law. 183. The California Tussock-moth. 184. Report of the Plant Pathologist to July 1, 1906. 385. Report of Progress in Cereal Investigations. 186. The Oidium of the Vine. 187. Commercial Fertilizers. (January, 1907.) 188. Lining of Ditches and Reservoirs to Prevent Seepage and 189. Commercial Fertilizers. (June, 1907.) 190. The Brown Rot of the Lemon. 191. California Peach Blight. UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. CIRCULARS. No. 1. Texas Fever. No. 23. 2. Blackleg. 24. 3. Hog Cholera. 25. 4. Anthrax. 5. Contagious Abortion in Cows. 26. 7. Remedies for Insects. 9. Asparagus Rust. 27. 10. Reading Course in Economic Entomology. ( Revision. ) 11. Fumigation Practice. 28. 12. Silk Culture. 13. The Culture of the Sugar Beet. 15. Recent Problems in Agriculture. 29. What a University Farm is For. 16. Notes on Seed- Wheat. 17. Why Agriculture Should Be Taught in the Public Schools. 18. Caterpillars on Oaks. 30. 19. Disinfection of Stables. 31. 20. Reading Course in Irrigation. 21. The Advancement of Agricultural Education. 32. 22. Defecation of Must for White 33. Wine. Pure Yeast in Wineries. Olive Pickling. Suggestions Regarding Exam- ination of Lands. Selection and Preparation of Vine Cuttings. Marly Subsoils and the Chlo- rosis or Yellowing of Citrus Trees. A Preliminary Progress Report of Cereal Investigations. 1905- 1907. Preliminary Announcement con- cerning Instruction in Practi- cal Agriculture upon the University Farm, Davisville, Cal. White Fly in California. The Agricultural College and Its Relationship to the Scheme of National Education. White Fly Eradication. Packing Prunes in Cans. Cane Sugar vs. "Beet Sugar. Copies may le had on application to DIRECTOR OF EXPERIMENT STATION, Berkeley, Cal. OFTHE UNIVERSITY OF ^. A L F^ n *^_ UNIVERSlVV (ff {JALIFORNIA PUBLICATIONS. COLLEGE OF AGRICULTURE, AGRICULTURAL EXPERIMENT STATION, THE BEST WINE GRAPES FOR CALIfORNIA. PRUNING YOUNG VINES. PRUNING THE SULTANINA. BY F. T. BIOLETTI. An ideal vine at second winter pruning. BULLETIN No. 193. (Berkeley, Cal., November, 1907.) SACRAMENTO: w. w. SHANNON, : : : : SUPERINTENDENT STATE PRINTING. 1907. BENJAMIN IDE WHEELER, Ph.D., LL.D., President of the University. EXPERIMENT STATION STAFF. E. J. WICKSON, M.A., Director and Horticulturist. E. W. HILGARD, Ph.D., LL.D., Chemist. W. A. SETCHELL, Ph.D., Botanist. ELWOOD MEAD, M.S., C.E., Irrigation Engineer. C. W. WOODWORTH, M.S., Entomologist. R. H. LOUGHRIDGE, Ph.D., Agricultural Geologist and Soil Physicist. (Soils, Alkali.) M. E. JAFFA, M.S., Nutrition Expert, in charge of the Poultry Station. G. W. SHAW, M.A., Ph.D., Agricultural Technologist, in charge of Cereal Stations. GEORGE E. COLBY, M.S., Chemist. (Fruits, Waters, Insecticides.) RALPH E. SMITH, B.S., Plant Pathologist and Superintendent of Southern California Pathological Laboratory and Experiment Station. A. R. WARD, B.S.A., D.V.M., Veterinarian and Bacteriologist. E. W. MAJOR, B.Agr., Animal Industry and Manager of University Farm. F. T. BIOLETTI, M.S., Viticulturist. (Grapes, Wine and Zymology.) H. M. HALL, M.S., Assistant Botanist. H. J. QUAYLE, A.B., Assistant Entomologist. W. T. CLARKE, B.S., Assistant Horticulturist and Superintendent of University Extension in Agriculture. JOHN S. BURD, B.S., Chemist, in charge of Fertilizer Control. C. M. HARING, D.V.M., Assistant Veterinarian and Bacteriologist. J. W. MILLS, Assistant Horticulturist, { Citrus Experiment station, Riverside. T. F. HUNT, B.S., " ) E. B. BABCOCK, B.S., Assistant Plant Pathologist. E. H. SMITH, M.S., Assistant Plant Pathologist. H. J. RAMSEY, M.S., Assistant Plant Pathologist, ) Southern California Pathologi- C. O. SMITH, M.S., " " " f cal Laboratory. Whittier. R. E. MANSELL, Assistant in Horticulture, in charge of Central Station Grounds. GEO. W. "LYONS, B.S., Assistant in Soil Laboratory. RALPH BENTON, B.S., Assistant in Entomology. A. J. GAUMNITZ, M.S., Assistant in Cereal Investigations. HANS C. HOLM, B.S., Assistant in Zymology. P. L. McCREARY, B.S., Laboratory Assistant in Fertilizer Control. C. WESTERGAARD, B.S., Assistant in Farm Mechanics. M. E. STOVER, B.S., Assistant in Agricultural Chemical Laboratory. RACHAEL CORR, M.A., Assistant in Cereal Laboratory. D. R. HOAGLAND, A.B., Assistant in Agricultural Chemical Laboratory. D. L. BUNNELL, Clerk to the Director. JOHN TUOHY, Patron, j. Tu i are Substation, Tulare. J. T. BEARSS, Foreman, } J. W. ROPER, Patron, ) University Forestry Station, Chico. E. C. MILLER, In charge, } ROY JONES, Patron, ) University Forestry Station, Santa Monica. N. D. INGHAM, Foreman, \ VINCENT J. HUNTLEY, Foreman of California Poultry Experiment Station, Petaluma. The Station publications (REPORTS AND BULLETINS), so long as avail- able, will be sent to any citizen of the State on application. THE BEST WINE GRAPES FOR CALIFORNIA, BY F. T. BIOLETTI. The question is often asked: "What are the best wine grapes for California?" It is a very difficult question to answer. If we modify it and ask, "What wine grape is it most advisable to plant?" the diffi- culty is lessened but not removed. The answer will depend greatly on the point of view. For the grape-grower it is one thing, for the wine- maker another, for the consumer still another, and for the good of the industry at large a compromise of all three. For the grape-grower who sells his grapes for so much a ton what- ever the quality, the question resolves itself into, " Which is the heaviest bearer?" For the consumer the question means either "What grape will pro- duce good wine at the minimum cost?" or "What grape will produce the best wine irrespective of cost?" according to the kind of consumer he happens to be. As quantity and quality are to a great extent inversely proportionate, these views are widely divergent. For the wine-maker the question is a little more complicated, but may be stated essentially as, "What grape can J handle with the most profit?" This profit will depend on the difference between the price he is forced to pay the grower for grapes and that which he can persuade the consumer to pay him for wine. For one class of consumers he must get cheap grapes, for the other he can afford to pay almost any price, providing they are of the right quality. For the good of the industry at large it is desirable that varieties should be planted which will produce as large a crop as is compatible with such quality as will maintain and extend the markets for our wine. These markets are varied in character. For some, cheapness is the essential factor; for others, quality. Cheap wines can be produced with profit only from heavy-bearing varieties grown in rich soil; wines of the highest quality only from fine varieties grown on hillsides or other locations where the crops are necessarily less. It is therefore unwise to plant poor-bearing varieties in the rich valleys where no variety can produce a fine wine. It is equally unwise to plant common varieties on the hill slopes of the Coast Ranges where no variety will produce heavy crops. The vineyards of the San Joaquin, Sacramento, and other valleys can not compete with the vineyards of the Coast Ranges in quality, and the latter can not compete with the former in cheapness. Each region has its own special advantages which, if properly used, will make grape-growing profitable in all, and instead of competing each 142 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. will be a help to the other. The danger to be feared by the grape- growers of the Coast Ranges from the production of dry wine in the interior is not competition, but lies in the bad reputation given to California wines by the production of spoiled and inferior wines. If the cheap wines of the valleys are uniformly good and sound the market for the high-priced fine wines of the hills will increase, and large quantities of the Coast Range wines will be used for blending with the valley wines to give them the acidity, flavor, and freshness which they lack. In order to obtain these results it is necessary that varieties suited to each region and to the kind of wine should be planted. No variety which is not capable of yielding from 5 to 8 tons per acre in the rich valley soils or from 1-| to 3 tons on the hill slopes should be considered. On the other hand, no variety which will not give a clean-tasting, agreeable wine in the valley or a wine of high quality on the hills should be planted, however heavily it may bear. To plant heavy- bearing inferior varieties such as Burger, Feher Szagos, Charbono, or Mataro on the hills of Napa or Santa Cruz is to throw away the chief advantage of the location. The same is true of planting poor-bearing varieties such as Verdelho, Chardonay, Pinot, or Cabernet Sauvignon in the plains of the San Joaquin. With these considerations in view, the following suggestions are made for planting in the chief regions of California: 1. Vineyard for Sweet Wine in the Interior Valleys. RED. Proportion. WHITE. Proportion. Grenache \ Palomino.. _ & Alicante Bouschet Beba ._. \ Tinta Madeira i Boal J The Grenache and Alicante Bouschet are heavy bearers with short pruning. The former naturally takes a port flavor and the latter insures sufficient color. The Tinta Madeira, when pruned properly, bears well and will increase the quality of the port wine. The Palomino is one of the heaviest and most regular bearers grown in California and is peculiarly suited for sherry making. It is the principal grape of the Spanish sherry district. The Beba bears nearly or quite as well as the Palomino and is of rather better quality. Both bear with short pruning. The Boal bears good crops and gives a sweet wine of high quality. 2. Vineyard for Dry Wine in the Interior Valleys. RED. Proportion. WHITE. Proportion. Valdepenas.. Burger & Lagrain J West's White Prolific | St. Macaire | Vernaccia Sarda The Valdepenas has been growing for nearly twenty years at the Tulare Experiment Station, and has always given regular and good crops BULLETIN 193. THE B EST WINE GRAPES FOR CALIFORNIA. 143 with short pruning. The dry red wine made from it has been in every way satisfactory and much superior to that made from Bouschet, Zin- fandel, or any of the varieties usually grown in the valley, and approaches more nearly than any other variety the wines of the cooler localities. This variety has been planted to some extent in the cooler localities, where it is completely out of place. In Napa its bearing is unsatisfactory and its wine harsh. The vine needs a hot climate to bring out its best qualities. The Lagrain and St. Macaire are valuable on account of their intense color, which at Tulare is equal to that of the Bouschets and is more stable. The St. Macaire is particularly recom- mended on account of its high acidity, which is extremely useful for the region. The Gros Mansenc retains its acid even better than the St. Macaire, and is also deeply colored, but it has not borne quite so well. The Burger has, fortunately, been planted extensively in the hotter parts of the interior, and probably no better choice could be made for the production of a cheap, light, neutral dry white wine in that region. Its acidity, which is excessive in the coast counties, is normal or even low in the interior. For this reason, and in order to give a little more character, it should be blended with such grapes as the West's White Prolific and the Vernaccia Sarda, which retain their acidity at Tulare better than any other white grapes tested. 3. Vineyard for Dry Wine in the Coast Counties. RED. Proportion. WHITE. Proportion. Petite Sirah Semillon Beclan. .._.. | Colombar Cabernet Sauvignon Sauvignon blanc The conditions of soil and climate in the hills and valleys of the Coast Ranges are so varied that it is much more difficult to give recom- mendations that will be of general use than in the case of the interior valleys. In some parts of some of the valleys the soil is so rich and productive that it is possible to grow grapes as cheaply as in the interior. The grapes recommended for the interior, however, would not in most cases be suitable on the Coast, owing to the difference in climate. As a rule, the grapes which are suitable to the hill slopes will do well in the valley, making up in quantity what they lose in quality. Of the many scores of red varieties which have been widely grown in this region, the Petite Sirah has undoubtedly given the most generally satisfactory results. Some growers are dissatisfied with its bearing, but most report that it produces as much as the Zinfandel. Ungrafted, it requires long pruning. Its wine is of excellent quality, but apt to be somewhat harsh. This harshness can be avoided by careful wine- making and by blending with a smooth variety such as the Beclan. The finest red wines which have ever been made in California are the product of the Cabernet Sauvignon. This variety, unfortunately, has 144 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. been rejected almost everywhere on account of its light crops. Very satisfactory crops, however, can be obtained if care is taken in selecting cuttings for planting and a suitable system of pruning adopted. This variety, like most others, moreover, bears better when grafted on a suit- able resistant stock. It is very much to be desired that a certain pro- portion of this variety should be planted in all the coast vineyards which are capable of producing a dry red wine of high quality. No white grape has given better results in both crop and quality than the Semillon. The Colombar (sometimes called the Sauvignon vert) has also proved itself a regular bearer, and, Avhile not of such high quality as the Semillon, it blends very well with that variety and serves to modify its aroma, which is sometimes excessive. The Sau- vignon blanc increases the quality of the wine, but like the Cabernet Sauvignon requires careful cutting, selection and pruning to give satisfactory crops. 4. Vineyard 'for Dry Wine in the cooler parts of the Coast Counties. RED. Proportion. WHITE. Proportion. Beclan f Frankeii Riesling f Blue Portuguese i Johannisberg Riesling.- $ In certain parts of the coast counties, owing to the frequent occurrence of ocean fogs, many varieties of vines do not ripen their fruit properly. By a careful selection of varieties, however, good crops of well-ripened grapes may be obtained. It is in these localities that the finest light wines, those most nearly resembling the wines of the Rhine, can be produced. The Beclan has shown itself especially suited to this region, and has the great advantage of being very resistant to oidium. The Blue Portuguese is a good bearer, ripens easily, and blended with Beclan gives a good wine of Burgundy type. The best Riesling wines are grown near the coast and, undoubtedly, profitable vineyards of the Rhine varieties can be grown in this region if proper methods of grape- growing and wine-making are adopted. Undoubtedly there are many excellent varieties of grapes that could be grown with profit which are not mentioned in the foregoing lists. The varieties mentioned are simply those which have given evidence of being most generally adapted to the more usual conditions. Under special conditions other varieties should be added to or substituted for those named. In planting a new vineyard it would be well often to choose those varieties which are best able, by blending, to correct the defects of the varieties already growing in the district If the bulk of the red grapes are deficient in color, it would be well to plant a larger proportion of deeply colored varieties. If most of the white grapes of the region are of poor, quality, lacking in character, flavor, or acidity, a larger planting of the finer varieties might be advisable. It is good BULLETIN 193. THE BEST WINE GRAPES FOR CALIFORNIA. 145 policy to plant something that has not already been planted in too large quantities, providing it is something suitable and for which there will be a demand. Moreover, a larger number of kinds ripening at different times would be a great convenience in a large vineyard, by allowing the gathering of the grapes to extend over a longer period. Finally, a few suggestions as to what " not to do." Don't plant Mataro, Feher Szagos, Charbono, Lenoir, or any variety which makes a poor wine everywhere. Don't plant Burger, Green Hungarian, Mourastel, Grenache, or any common heavy-bearing varieties on the hill slopes of the Coast Ranges. Vineyards in such situations must produce fine wines, or they will not be profitable. Don't plant Chardonay, Pinot, Cabernet Sauvignon, Malbec, or any light-bearing varieties in rich valley soils. No variety will make fine, high-priced wine in such situations, and heavy bearers are essential to the production of cheap wine. Don't plant Zinfandel, Alicante Bouschet, or any of the varieties which have already been planted in large quantities, unless one is sure that the conditions of his soil and locality are peculiarly favorable to these varieties and will allow him to compete successfully. WINE GRAPES RECOMMENDED FOR CALIFORNIA. FOR COAST COUNTIES. Red Wine Grapes. White Wine Grapes. 1. Petite Sirah. 1. Semillon. 2. Cabernet Sauvignon. 2. Colombar (Sauvignon vert). 3. Beclan. 3. Sauvignon blanc. 4. Tannat. 4. Franken Riesling. 5. Serine. 5. Johannisberger. 6. Mondeuse. 6. Traminer. 7. Blue Portuguese. 7. Peverella. 8. Verdot. FOR INTERIOR VALLEYS. Red Wine Grapes. White Wine Grapes. 1. Valdepenas. 1. Burger. 2. St. Macaire. 2. West's White Prolific. 3. Lagrain. 3. Vernaccia Sarda. 4. Gros Mansenc. 4. Marsanne. 5. Barbera. 5. Folle blanche. 6. Refosco. 7. Pagadebito. FOR SWEET WINES. Red Grapes. i White Grapes. 1. Grenache. 1. Palomino. 2. Alicante Bouschet/ 2. Beba. 3. Tinta Madeira. J 3. Boal. 4. California Black Malvoisie. 4. Perruno. 5. Monica. * 5. Mantuo. 6. Mission. ' 6. Mourisco branco. 7. Mourastel. 7. Pedro Ximenez. 8. Tinta Amarella. x 146 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. PRUNING AND TRAINING OF YOUNG VINES. The first two or three years of the life of a vineyard are perhaps the most important from the point of view of the profit and satisfaction to be obtained from it later. Vines which are neglected or improperly treated in youth can never be given that shape which is indispensable for the maximum returns and the minimum labor. Thousands of acres of new vineyard have been planted during the last two years, and, without attempting to write a complete treatise on vine pruning, a few practical suggestions regarding the treatment of young vines should be useful. /Whatever the variety of vine and whatever the\ j system of pruning to be ultimately adopted, the f I treatment for the first two and even three years \ Us practically identical. FIRST YEAR. Making Cuttings. The considerations which should govern us in the choice and making of cuttings have been given in Circular No. 26, of this Station, " Selection and Preparation of Vine- Cuttings." The mechanical part only is reviewed here. The cuttings should be made from w r ell-ripened canes of medium thickness and of greater or less length, according to the climate and soil of the vineyard in which they are to be planted. The range will be from 10 to 18 inches. Cuttings are most conveniently made by means of ordinary one-hand pruning shears. In mak- ing them, the lower cut should be made just below a bud, and the upper just above a bud. These cuts should be made as near the bud as is possible without danger of destroying or remov- ing the diaphragm (see Fig. 2). It is best to remove the upper bud, either when making the cuttings or afterwards, though this is not absolutely necessary. The bud from which growth is expected is the second from the top. The reason for leaving the internode above is to protect the second bud and to insure its strong growth. It is for this reason that the diaphragm should be left. If removed, the pith in the upper FIG. 1. Properly made cuttings. BULLETIN 193. PRUNING AND TRAINING OF YOUNG VINES. 147 internode will be exposed to alternate wetting and drying, and may decay, thus weakening or killing the bud below. In planting, the cutting should be placed with just one bud above the surface of the ground, as indicated by the dotted line in Fig. 1. It is a great mistake to leave more than one bud out of the ground, as this increases the danger of drying out. Pruning Rooted Vines. A young rooted vine before planting should have all its roots shortened to from 4 to 6 inches, according to their vigor (see Fig. 3, A, B, C). If the soil has been very deeply plowed and it is desired to plant the vines with a dibble, there is no objection to cutting back the roots to stubs i of an inch long (see Fig. 3, D). Such a vine will make better growth in deeply prepared soil than one with longer roots planted with a spade in shallow-plowed soil. The top of the vine should be thinned to one cane, the strongest and most upright being left. This cane must be shortened to two good buds, N. Node. FIG. 2. Structure of Vine Cane. d. Diaphragm. I. Internode. P. Pith. making the cut close to an internode, as in making cuttings (see Fig. 3, C, D). The pruning of rooted bench grafts is practically the same as that of ordinary rooted vines, though the cutting back of the single cane to two buds is best deferred until after planting and just as the buds com- mence to swell (see Fig. 3, B). This affords some protection to the graft, and makes it less likely to dry* out before the sap starts and the young rootlets are formed. All scion roots (CR) above the union (U) and all suckers (SS) from below the union should be carefully removed (Fig. 3, A). During the summer of the year the vines are planted, no pruning or training of any kind is needed in most cases. For this reason it is nearly always unnecessary to stake the vines when they are planted. The only exception to this is when strong-rooted vines are planted in a rich, moist soil in which they will make a very large growth the first year. In this case it is desirable, though not quite necessary, to stake 148 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. the vines immediately after planting and to adopt the method of summer treatment described below for the second year. In most cases it is best to allow all the shoots to remain to feed the vine and to insure a good root growth the first year. Staking. In the autumn or winter fol- lowing planting, the vines should be staked, either before or after pruning, but in any case some time before the buds start in the spring. B It FIG. 3. Methods of pruning rooted vines. A. Rooted vine (bench graft) before pruning r, union. &S, stock suckers. CR, scion root. B. Rooted bench-graft pruned for planting. C. Rooted cutting pruned for planting. D. Rooted cutting pruned for planting with dibble. BULLETIN 193. PRUNING AND TRAINING OF YOUNG VINES. 149 The kind of stake used will depend on the variety of vine and on the method of pruning to be ultimately adopted. For ordinary short- pruning, the stake should be of such length that, after being driven into the ground, sufficient will be below the surface to keep it firm and prevent its being loosened by the force of the wind acting on the vine which is tied to it, and sufficient above the surface to extend 1 or 2 inches above the height at w r hich it is intended to head the vines. It should be from l^r to 1^ inches square, according to its length. In firm ground, for small-growing vines such as Zinfandel, a stake li by 1^ inches and 27 inches long will be sufficient. This will allow 15 inches to be driven into -the ground and leave 12 inches above, which is enough for vines to be headed at 10 inches. If the ground is loose or sandy a 30-inch stake driven 18 inches into the ground will be ' needed. For strong-growing varieties, such as Carignane or Tokay? especially when planted in rich soil, a stake 1^ by 1^ inches and 36 inches long will be necessary, and 15 or 18 inches of this should be left above the ground. This will permit the heading of the vines at 15 inches. If the vines are to be trellised with one wire, a 36-inch stake driven 18 inches into the ground is the proper length. If two wires are to be used, a 48-inch stake will be needed, leaving 30 inches above the surface. If the vines are to be pruned long and the canes tied to the stake, a 5-foot stake will usualty be needed, and this must be stronger, 2 by 2 inches square. This stake should be driven 2 feet into the ground. These dimensions are all smaller than are usual in California, but are quite sufficient for all practical purposes. The stake should be placed 1 to 2 inches from the vine on the side opposite to the prevailing heavy winds. The force of the wind will thus keep the vine pressed against the stake and the tying material is less liable to break. First Winter Pruning. In California, the young vines may be pruned at any time after the leaves have fallen, except in sections very subject to spring frosts, where it is sometimes advisable to defer the pruning until after the top buds of the canes start. The way the vines are to be pruned will depend altogether on the growth they have made. If the growth has been small the tops are pruned exactly like rooted vines before planting. All the canes are removed entirely, except the strongest, and this is cut back to two buds, as in Fig. 3, C, D (see Fig. 4, a). Any vines which have made a strong growth and possess at least one cane of which a sufficient length is well ripened may be pruned for tying up. All the canes are removed entirely, except the strongest, and this is cut back to 10, 15, or 18 inches, according to the height at which it is intended to head the vine (see Fig. 5, a). The top cut is made 150 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. through a bud, just as in making cuttings. This will facilitate tying up and insure the healthy growth of the top bud. Sometimes, even when the vine has made sufficient growth, the canes are prostrate or crooked and none can be tied up straight to the stake. In this case the vine must be pruned like a weak vine that is, thinned to one cane and this cane cut back to two buds. In no case should two canes of any length be left, and in all cases where it is impossible to obtain the full length of well-ripened wood for tying up, the cane should be cut back to two buds. It is very bad practice to leave some of the canes of intermediate length, as this causes FIG. 4. b c Treatment of an average vine during second season. a. Winter pruning. b. Spring pruning removal of suckers (S) and thinning of shoots (W). c. Summer treatment tying to stake and topping. the vines to head out at various heights and produces an irregularity of shape which can never be remedied and which interferes with regular pruning, cultivation, and other vineyard work. The idea to be kept in mind is to cut back each winter nearly to the ground that is, to two buds until a cane is produced with a length of well-ripened wood and good buds equal to the height at which the vine is to be headed. It is very important that this cane should be straight, healthy, and well-ripened, as it is from it that the trunk of the mature vine develops. All the vines on which a cane has been left should be carefully tied up. Two ties will be needed in most cases. A half hitch should be made around the cane below the swelling left by the bud which has been removed, and the cane tied firmly to the top of the stake. BULLETIN 193. PRUNING AND TRAINING OF YOUNG VINES. 151 Another tie is made about half-way down the stake. The lower tie need not be very tight, and in any case the tying material should not be passed completely around the cane, except above the top bud, or the vine will be strangled when it commences to grow (see Fig. 5, a). Any kind of string or twine, sufficiently strong to withstand the pressure of the growing vine in a heavy wind, may be used. Binding twine, or a single strand of good baling rope, is suitable. No. 16 or 17 galvanized wire is preferred by some and is better than string, if care is taken to remove the bottom ties the following year before they strangle the vine. Wire is a little more expensive and takes a little longer to put on than string, but holds the vines better and can be used for several years. SECOND YEAR. Summer Pruning. The treatment during the second and third spring and summer is of great importance to the future welfare of the vine. A little judicious care at this period will avert many troubles in later years. It will be necessary to go over the vineyard four or five times to do the suckering, topping, and tying which are necessary. The shoots starting from the vines which have been cut back to two buds should be thinned to a single one. This thinning should be done as soon as possible in such a way that it is never necessary to remove a shoot more than 3 or 4 inches long (see Fig. 4, b). If the thinning is deferred until the shoots are a foot or more long the vine will be weakened by the removal of so much foliage. If the thinning cannot be done early, it is better not to do it at all. The object of this thinning is to throw all the force and growth of the vine into the cane which is to form, finally, the trunk of the vine. If it is done too late not only does the growth not go into this cane, but the vine is weakened so much that this cane does not grow so well as it would have done without thinning. The first thinning can be done with the first hoeing, and the second with the suckering. The suckering consists of the removal of all shoots which come from below the ground. These also should be removed as early as practicable, both to avoid weakening the vine by the removal of mature leaves and also because a young sucker is much more easily separated from the vine at this time. Every sucker must be cut or broken off at the point where it originates. If a little piece of the sucker is left, several new suckers will start at the same place. The more completely the suckering is done during the first two years, the less trouble in this respect there will be in later years. This is particularly true of grafted vines. A few weeks after the first thinning, the single shoot which has been left will have grown 10 or 15 inches. At this length it should be tied up to the stake (see Fig. 4, c). If this tying is neglected or deferred 152 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. too long, a heavy wind is very liable to break off the whole shoot. A piece of string tied rather loosely about the middle of the shoot is all that is needed. If the vines are to be headed high (18 inches) another tie near the top of the stake may be necessary later. For vines which are making only a moderate growth this is all the treatment needed during the summer. Strong-growing vines in rich soil, however, should be topped. Topping. The object of this topping is to force the shoot to send out laterals at the right height above the surface of the soil, to be used as FIG. 5. Treatment oi average vine during the third season, or of a vigorous vine during the second. a. Vine pruned to one cane and tied to stake. b. Removal of suckers (S) and lower shoots (W) in spring. c. Vine in summer at time of pinching. spurs during the following year. This topping is an operation which requires a good deal of judgment. If the topping is done too soon, laterals will not start, but a new terminal shoot will be formed. This is not a serious defect, however, but simply necessitates a second top- ping two or three weeks later. Neither will the laterals start if the topping is done too late, or if they start they will not mature, and the vine is weakened by the removal of foliage without any compensating advantage. Until experience has shown the proper time for the variety and locality, it is best to top when the shoot has grown to from 8 to 12 inches above the top of the stake, and if necessary top again later. BULLETIN 193. PRUNING AND TRAINING OF YOUNG VINES. 153 The shoot should be topped within 1 or 2 inches of the top of the stake, if the stakes have been chosen and driven as advised above (see Fig. 4, c). This will insure the growth of laterals just where they are needed for the next winter pruning. The vines on which a cane has been left and tied up during the pre- ceding winter must be treated a little differently. The removal of underground shoots or suckers is the same. Instead of thinning out the shoots to a single one, as for the vines just described, all the shoots should be left to grow, except those too near the ground (see. Fig. 5, b). As a rule, all shoots between the ground and the middle of the stakes should be taken off. It is even more important that this should be done early than in the case described above. If the lower shoots are allowed to become large and then removed, not only is the vine weak- ened by the removal of mature leaves, but the stem of the vine is suddenly exposed to the direct rays of the hot sun and is very liable to injury. This injury does not show by a peeling off of the bark as with fruit trees, but by a general weakening and dwarfing of the vine. The shoots coming' from the upper half of the cane are to form the spurs for the following winter pruning, and can often be left to grow without further treatment. If the growth is very rapid and succulent, however, it is necessary to pinch them, or the first heavy wind may break them off (see Fig. 5, c). Pinching consists of the removal of 1 or 2 inches of growth at the extreme tip of the shoot. This delays the growth in length temporarily and gives the shoot time to strengthen its tissues before its length gives too much leverage to the wind. This pinching usually has to be repeated at least once. Pinching may be replaced by topping a few weeks later, but the latter is somewhat weakening to the vine. In all summer pruning that is, removal of green shoots and leaves of young vines, two things should be kept in mind: First, that all summer pruning is weakening; second, that the object of summer prun- ing of young vines is to direct the growth as much as possible into those parts which are to become permanent portions of the mature vine. The weakening effect is almost nil if the shoots or tips are removed when they are very small, but may be very serious if large shoots are removed or heavily topped. When a large shoot covered with leaves is removed it 'is a total loss to the vine. .When a small shoot is removed the food materials which would have gone into that shoot are diverted to the shoots that remain, and the vigor and size of the latter are increased. 154 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. THIRD YEAR. Winter Pruning. After the leaves have fallen at the end of the third summer every vine should have a well-formed, straight stem with two, three, or more canes growing from the upper part, and the formation of the "head" or crown should commence. Any vines which have not been brought to this condition must be pruned like two- or one-year- old vines, as the case may be. If the work up to this point has been well done, the formation of the head is a simple matter. It consists in leaving two, three, or four spurs, FIG. 6. Three-year-old vines after pruning. a. Average vine with two spurs. b. Vigorous vines with three spurs, the lowest of which is to be removed the following year. c. Vigorous vine with three spurs. arranged as symmetrically as possible near the top of the vine. The stronger the vine, as evidenced by the number, length, and thick- ness of the canes, the larger the number of spurs and buds that should be left. A spur consists of the basal portion of a cane, and normally of two full internodes. This leaves two buds besides the base bud. The number of buds to leave on a spur depends on the strength or thickness of the cane from which the spur is made. A thin, or weak, cane should be cut back to one bud or even to the base bud. A strong cane, on the other hand, should be left with three buds besides the base bud. The pruning of each vine requires judgment, and it is impossible to BULLETIN 193. PRUNING THE SULTANINA. 155 give an inflexible rule to follow. The ideal of a perfect vine should be kept in mind and each vine pruned as nearly in accordance with this ideal as circumstances permit. Fig. 6 and the illustration on the cover represent nearly perfect three-year-old vines consisting of two or three symmetrically placed spurs of two buds each ne"ar the top of the stem. Sometimes it is necessary to leave a spur lower down (see Fig. 6, b}. This spur will be removed the following year after it has produced two or three bunches of grapes. Sometimes a vine may be very vigorous but have only4wo canes properly placed for making spurs. In this case the spurs should be left longer three buds and even in extreme cases four buds long. PRUNING THE SULTANINA.* This variety has shown itself extremely irregular in bearing in many vineyards of California. The variations in the crop of different years in the same vineyard, of adjacent vineyards in the same district, and of different vines in the same vineyard are very much greater than is usual with most other varieties. The cause of this seems to be due, in great part at least, to defective pruning. If we inquire into the history of any Sultanina vineyard we find very commonly the following sequence of events: During the first four, live or six years the vines were pruned short, grew with extraordinary vigor, but produced very few grapes. The following year the owner, hearing that long pruning was necessary, left two, three, four, or more canes four or five feet long and tied them up vertically to a high stake. This usually resulted in a large crop. The same method, as nearly as practicable, was followed during subsequent years, with gradually diminishing success, until about the third year of long pruning the crops had become unsatisfactory again. The reason for this sequence of events is easy to comprehend when we understand the principles of long pruning and the special charac- teristics of the Sultanina. This variety bears well only on long canes, so that so long as short pruning is practiced the crops are unsatisfactory. The first year in which long canes are left the crop is good, because a large proportion of the canes tied up consist of bearing wood. Provision is seldom made, however, for the growth of new canes from the stump to furnish bearing wood for the following years. The result is, that after the second or third year all the bearing wood is at the top of the stake, and the vine must be pruned short again or suckers and watersprouts left as long *This is the correct name of the " Thompson's Seedless." 156 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. canes. Whichever of these two alternatives is chosen the result will be unsatisfactory. A common condition of a Sultanina vine after the first year of long FIG. 7. Sultanina vine showing effect of tying fruit canes in a vertical position. (From a photograph.) S. Suckers and watersprouts. F. Strong fruit wood. /. Weak fruit wood. C. Fruit canes of the previous year which have just borne a crop. pruning is shown in Fig. 7. If the fruit canes (C, C) of the previous years are removed, nothing remains but the unfruitful suckers and watersprouts (S, S). If the old fruit canes (C, C) are left there is an BULLETIN 193. PRUNING THE SULTANINA. 157 abundance of fruit wood (F, F), but it is so near the top of the stake that if fruit canes are left there is nothing to which to tie them. If this fruit wood is left and pruned short we get a vine like that shown in Fig. 8, which is worse than an ordinary short-pruned vine. This condition may be avoided for a year or two if, besides the fruit FIG. Last stage of a Sultanina vine which has been pruned long and the canes tied up vertically. canes (C, C), we leave also some short spurs of one or two buds on the- main stump. The canes from these spurs will consist of fruit wood and they may be used for fruit canes the following year. Unfortu- nately these spurs are so shaded by the foliage on the fruit canes that they do not always produce vigorous wood, and finally they fail to grow at all. UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Two methods have been successfully used to insure the growth of new fruit wood every year in a position where it can be utilized. The first consists in bending the fruit canes into a circle, as illustrated in Fig. 9. This diminishes the tendency of the sap of the vine to go to the end of the fruit canes. The consequence is that more shoots start on the lower parts of the fruit canes. All the shoots on these canes are made weaker and more fruitful by the bending, and at the same time the sap pressure is increased and causes strong shoots to start from the wood spurs left near the ba e es of the fruit canes. These shoots are used for fruit canes at the following winter pruning, and new wood spurs are then left for the next year. The tying and bending of the fruit canes require great care, and repeated suckering and removal of watersprouts are necessary to insure a strong growth of replac- ing canes on the \vood spurs. This method can be used successfully only by skillful hands. The other method re- quires some form of trellis. The most prac- ticable trellis is a wire FIG. 9. Showing method of bending fruit canes to Stretched along the 1'OWS insure growth of shoots from replacing spurs. at about 1^ or 2 feet above the surface of the soil. For very vigorous vines in rich soil a second wire 12 inches above the first is advisable. The pruning is the same as for the method just described. The fruit canes, however, instead of being bent in a circle and tied to the stake, are placed in a horizontal position and tied to the wire. The horizontal position has the same effect as curving in promoting the starting of BULLETIN 193. PRUNING THE SULTANINA. 159 more shoots on the fruit canes and the consequent production of more bunches of grapes. At the same time the buds on the wood spurs are forced to start, and not being shaded they tend to grow vigorously. It is best to tie the shoots from the wood spurs in a vertical position to the stake, and they should not be topped. This is a modification of what i known as the Guyot system of pruning, and is not only theo- retically correct, but is easy to explain to pruners, and can be carried out much more perfectly than the first method with ordinary labor. Whatever system of winter pruning is adopted with the Sultanina, 160 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. careful summer pruning, suckering, sprouting, and topping are neces- sary for the best results. This variety has a tendency to send out large numbers of suckers from below ground and watersprouts from the old wood. These shoots are usually sterile, grow vigorously, and unless removed in time divert the energies of the vine from the fruit and fruit shoots. Two or three times during the spring the vineyard should be gone over carefully and all sterile shoots which are not needed to balance the vine or to replace weak or missing arms should be removed. This removal of shoots should be done in such a way that no shoot longer than 12 inches is ever removed. If the water- sprouts are allowed to grow large their removal weakens the vine. The shoots which are to give fruit canes for the following year should not be topped. The shoots from the horizontal fruit canes on the trellises, however, will set their fruit better and are less likely to be broken by the wind if they are pinched or topped early. No summer pruning of any kind should be done while the vines are blossoming, or for a week or ten days before the blossoms open. STATION PUBLICATIONS. STATION PUBLICATIONS AVAILABLE FOR DISTRIBUTION. REPORTS. 1896. Report of the Viticultural Work during the seasons 1887-93, with data regarding the Vintages of 1894-95. 1897. Resistant Vines, their Selection, Adaptation, and Grafting. Appendix to Viticultural Report for 1896. 1898. Partial Report of Work of Agricultural Experiment Station for the years 1895-96 and 1896-97. 1900. Report of the Agricultural Experiment Station for the year 1897-98. 1902. Report of the Agricultural Experiment Station for 1898-1901. 1903. Report of the Agricultural Experiment Station for 1901-1903. 1904. Twenty-second Report of the Agricultural Experiment Station for, 1903-1904. TECHNICAL BULLETINS ENTOMOLOGICAL SERIES. Vol. 1, No. 1 Wing Veins of Insects. No. 2 Catalogue of the Ephydridae. BULLETINS. Reprint. Endurance of Drought in Soils of the Arid Region. No. 128. Nature, Value and Utilization of Alkali Lands, and Tolerance of Alkali. (Revised and Reprint, 1905.) 133. Tolerance of Alkali by Various Cultures. 140. Lands of the Colorado Delta in Salton Basin, and Supplement. 141. Deciduous Fruits at Paso Robles. 142. Grasshoppers in California. 144. The Peach- Worm. 147. Culture Work of the Substations. 148. Resistant Vines and their Hybrids. 149. California Sugar Industry. 150. The Value of Oak Leaves for Forage. 151. Arsenical Insecticides. 152. Fumigation Dosage. 153. Spraying with Distillates. 154. Sulfur Sprays for Red Spider. 156. Fowl Cholera. 158. California Olive Oil ; its Manufacture. 159. Contribution to the Study of Fermentation. 160. The Hop Aphis. 161. Tuberculosis in Fowls. (Reprint.) 162. Commercial Fertilizers. (Dec. 1, 1904.) 163. Pear Scab. 164. Poultry Feeding and Proprietary Foods. (Reprint.) 165. Asparagus and Asparagus Rust in California. 166. Spraying for Scale Insects. 167. Manufacture of Dry Wines in Hot Countries. 168. Observations on Some Vine Diseases in Sonoma County. 169. Tolerance of the Sugar Beet for Alkali. 170. Studies in Grasshopper Control. 171. Commercial Fertilizers. (June 30, 1905.) 172. Further Experience in Asparagus Rust Control. 173. Commercial Fertilizers. (December, 1905.) 174. A New Wine-Cooling Machine. 175. Tomato Diseases in California. 176. Sugar Beets in the San Joaquin Valley. 177. A New Method of Making Dry Red Wine. 178. Mosquito Control. 179. Commercial Fertilizers. (June, 1906.) 180. Resistant Vineyards. 181. The Selection of Seed-Wheat. 182. Analysis of Paris Green and Lead Arsenate. Proposed Insecticide Law. 183. The California Tussock-moth. 184. Report of the Plant Pathologist to July 1, 1906. 185. Report of Progress in Cereal Investigations. 186. The Oidium of the Vine. 187. Commercial Fertilizers. (January, 1907.) 188. Lining of Ditches and Reservoirs to Prevent Seepage Losses. 189. Commercial Fertilizers. (June, 1907.) 190. The Brown Rot of the Lemon. 191. California Peach Blight. 192. Insects Injurious to the Vine in California. UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. CIRCULARS. No. 1. Texas Fever. No. 23. 2. Blackleg. 24. 3. Hog Cholera. 25. 4. Anthrax. 5. Contagious Abortion in Cows. 26. 7. Remedies for Insects. 9. Asparagus Rust. 27. 10. Reading Course in Economic Entomology. ( Revision. ) 11. Fumigation Practice. 28. 12. Silk Culture. 13. The Culture of the Sugar Beet. 15. Recent Problems in Agriculture. 29. What a University Farm is For. 16. Notes on Seed-Wheat. 17. Why Agriculture Should be Taught in the Public Schools. 18. Caterpillars on Oaks. 30. 19. Disinfection of Stables. 31. 20. Reading Course in Irrigation. 21. The Advancement of Agricultural Education. 32. 22. Defecation of Must for White 33. Wine. Pure Yeast in Wineries. Olive Pickling. Suggestions Regarding Exam- ination of Lands. Selection and Preparation of Vine Cuttings. Marly Subsoils and the Chlo- rosis or Yellowing of Citrus Trees. A Preliminary Progress Report of Cereal Investigations, 1905-07. Preliminary Announcement Con- cerning Instruction in Prac- tical Agriculture upon the University Farm, Davisville, California. White Fly in California. The Agricultural College and Its Relationship to the Scheme of National Education. White Fly Eradication. Packing Prunes in Cans. Cane Sugar vs. Beet Sugar. Copies may be had on application to DIRECTOR OF EXPERIMENT STATION, Berkeley, Cal. UNIVERSITY OF CALIFORNIA PUBLICATIONS. COLLEfiE OK AGRICULTURE. AGRICULTURAL EXPERIMENT STATION, BERKELEY, CALIFORNIA. THE CALIFORNIA GRAPE ROOT-WORM BY H. J. QUAYLE. BULLETIN No. 195. (Berkeley, (Jal., July, 1908.) SACRAMENTO: W. \V. SHANNON, ! I : : SUPERINTENDENT STATE PRINTING. 1908. BENJAMIN IDE WHEELER, Ph.D., LL.D., President of the University. EXPERIMENT STATION STAFF. E. J. WICKSON, M.A., Director and Horticulturist. E. W. HILGARD, Ph.D., LL.D., Chemist. W. A. SETCHELL, Ph.D., Botanist. ELWOOD MEAD, M.S., C.E., Irrigation Engineer. (Absent on leave.) LEROY ANDERSON, Ph.D., Dairy Industry and Superintendent University Farm. M. E. JAFFA, M.S., Nutrition Expert, in charge of the Poultry Station. C. W. WOODWORTH, M.S., Entomologist. R. H. LOUGHRIDGE, Ph.D., Soil Chemist and Physicist. G. W. SHAW, M.A., Ph.D., Agricultural Technologist, in charge of Cereal Stations. GEORGE E. COLBY, M.S., Chemist. (Fruits, Waters, Insecticides.) RALPH E. SMITH, B.S., Plant Pathologist and Superintendent of Southern California Pathological Laboratory and Experiment Station. Whittier. A. R. WARD, B.S.A., D.V.M., Veterinarian and Bacteriologist. E. W. MAJOR, B.Agr., Animal Industry. H. M. HALL, M.S., Assistant Botanist. H. J. QUAYLE, A.B., Assistant Entomologist. Whittier. W. T. CLARKE, B.S., Assistant Horticulturist and Superintendent of University Extension in Agriculture. JOHN S. BURD, B.S., Chemist, in charge of Fertilizer Control. C. M. HARING, D.V.M., Assistant Veterinarian and Bacteriologist. H. A. HOPPER, B.S.A., Assistant in Dairy Husbandry. J. H. NORTON, M.S., Assistant Chemist in charge Fertilizer citrus Experiment Stattm ' T. FHUNT, BS., Assistant Horticulturist, E. B. BABCOCK, B.S., Assistant Plant Pathologist. E. H. SMITH, M.S., Assistant Plant Pathologist. F. L. YEAW, B.S., Assistant Plant Pathologist. H. J. RAMSEY, M.S., Assistant Plant Pathologist, ) Southern California Patholog- C. O. SMITH, M.S., " " " f ical Laboratory. Whittier. R. E. MANSELL, Assistant in Horticulture, in charge of Central Station Grounds. RALPH BENTON, B.S., B.L., Assistant in Entomology. A. J. GAUMNITZ, M.S., Assistant in Cereal Investigations. RACHAEL CORR, M.A., Assistant in Cereal Laboratory. HANS C. HOLM, B.S., Assistant in Zymology. P. L. McCREARY, B.S., Laboratory Assistant in Fertilizer Control. F. E. JOHNSON, B. L., Assistant in Soil Laboratory. M. E. STOVER, B.S., Assistant in Agricultural Chemical Laboratory. D. R. HOAGLAND, A.B., Assistant in Agricultural Chemical Laboratory. CHARLES FUCHS, Curator Entomological Museum. P. L. HIBBARD, B.S., Assistant Fertilizer Control Laboratory. M. E. SHERWIN, Field Assistant in Agronomy. W. H. VOLCK, Field Assistant in Entomology. Watsonville. E. L. MORRIS, B.S., Field Assistant in Entomology. San Jose. J. S. HUNTER, Field Assistant in Entomology. San Mateo. D. L. BUNNELL, Clerk to the Director. JOHN TUOHY, Patron, ) Tulare Substation Tulare. J. T. BEARSS, Foreman, f University Forestry Station, Chico. E. C. MILLER, In charge, \ ROY JONES, Patron, \ University Forestry Station, Santa Monica. N. D. INGHAM, Foreman, ]' VINCENT J. HUNTLEY, Foreman of California Poultry Experiment Station, Petaluma. The Station publications (REPORTS AND BULLETINS), so long as avail- able, will be sent to any citizen of the State on application. THE CALIFORNIA GRAPE ROOT-WORM. (Adoxus obscurus Linn.) BY H. J. QUAYLE. The California Grape Root-worm is an insect that attacks both the roots and the growing parts of the vine above ground. It has been known to attack the leaves of the vine in this State for a good many years, but until a year or two ago it was unknown as a root feeder. It is similar in its life history and mode of attack to the well-known grape root-worm of the Eastern States, which is one of the worst pests that the vineyardists there have to wage war against. Our species has been doing considerable damage during the past two or three years, and it promises to be an important enemy of the vine in California. Early History in Europe. The first account of this insect, which leaves little doubt as to its identity, was given by Aldrovandi in 1602. x It is one of the important pests of the vine in France, as is shown by the amount of literature on the insect that has appeared in that country. Pluchi 2 in 1732 stated that it passed the winter in the ground, and this is the first suggestion we have of its underground habits, although it was not actually known by this author to feed upon the roots. The first authentic observation on the root-feeding habits appears to have been made in 1849 by Demermety, 3 who found it feeding upon the roots of vines in France. It has received rather careful attention from a number of observers in Europe, but probably the most complete account is given in Mayet's "Insectes de la Vigne. " It also occurs, as a grape pest, in Germany, Italy, and Algeria, as well as in France. In California. The first account of this insect occurring on vines in California, so far as we have been able to find, is a brief notice in the 1 'Pacific Rural Press" for May 29, 1880. It is here stated that " every spring for the last few years there have been received specimens of a dark colored beetle about one fifth of an inch long which eats the leaves of the grapevine until almost skeletonized." It is doubtful from this account just what beetle is referred to, but the description of the beetle and its work on the leaves, and the time of the year of its occurrence, 1 Des Insectes, p. 472. 2 Spectacle de la Nature ; Paris. 3 Jour. d'Agr. de Dijon. 2 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. suggests the root beetle. Moreover, Professor Wickson who was horti- cultural editor of the "Press" at the time, remembers that the article had reference to this species as we now know it, and not to the flea-beetle with which it has been commonly confused. The first full account of its occurrence in this State appears in an article by Matthew Cooke 1 in 1883. He confuses it with the flea-beetle, but he gives it the scientific name of Adoxus vitis, and from his account there is no mistaking the insect to which he refers. He states that "it was reported from at least six of the vire-growing sections of the State in 1882, and in 1883 was destroying the vines infested. One vineyard in the vicinity of Sacramento was damaged seriously that spring. Its mode of attack is similar to that of the steel-blue flea- beetle (Haltica chalybea 111.), and it frequently damages young vines to such an extent that they die. It is an insect enemy of the vine that must be eradicated." There is nothing said about the life history in this account, except that it attacks the vine in the same way as the flea-beetle. It is also given the common name of "Imported Grape Flea-beetle," and we therefore infer that he knew nothing of its attacking the roots. Neither is there anything in the literature of the State which has appeared since that would indicate that it is a root feeder. Its economic status as given by Cooke was based entirely on the damage done to the leaves. Important as that is, it is really of much less consequence than the attack on the roots, as is now known to be the case. Accounts of injury by this beetle have appeared from time to time since in the press of the State. Alexander Craw 2 then State quarantine officer, gave a short account of the beetle in 1897. He described its attack on the leaves, and figured a leaf showing the char- acteristic work of the beetle, but was apparently unaware of its under- ground habits. Riley and Howard 3 in 1891 stated that "In Europe Adoxus vitis is injurious to the grape, the larva? feeding on the roots and the beetle destroying the leaves, whereas in America it is only known to attack a wild plant (Epttobium). Mr. E. Dupont has recently investigated the subject of oviposition and finds that it occurs only on the foliage, the young larva afterwards entering the ground. The life history of Adoxus is thus in conformity with that of an allied species, Chryso- clius auratus which lives on Apocynum and rosoemifolium. We have found the eggs on the leaves and the larvae underground feeding on the roots. The nearest North American allies of Adoxus, viz., the species of Fidia, also infest the grapevine, but their life histories have 1 Injurious Insects of the Orchard and Vineyard, 1883. 2 Destructive Insects, 1897. 3 Insect Life, vol. Ill, p. 349. BULLETIN 195. CALIFORNIA GRAPE ROOT-WORM. 3 never been investigated. ' ' The first actual observation on the root-feed- ing habits on the grape in this country, so far as we know, was made by Mr. 0. Butler of this station, who found it on the roots of vines near Lodi in 1905. Its Name. A beetle was described in 1602 by Aldrovandi, 1 which seems to answer the description of this species ; but it was placed in the wrong group by this author, and it was also before the adoption of the binomial system of nomenclature. It has been described under two or three different generic names since, but the one now adopted is Adoxus, given by Kirby in 1837. Linnaeus in 1741 described a beetle, to which he gave the specific name obscunts. This is now known as Adoxus obscurus, and is the name that has been applied to the black form of the beetle occurring in California and elsewhere in the United States. Mayet 2 states that obscurus Linn, is somewhat larger than vitis, entirely black, and found on a plant (Epilobium) of the marshy prairies, sometimes upon "trifli" clover, but never on the vine. Dr. Horn 3 states that the only known species of the genus inhabits- Europe and the northern part of our own continent, and that it varies in a similar manner in both regions. In California it is certain that both the black and brown forms are the same species. Wherever the beetle was seen during the past two years the two forms occurred in about equal numbers, and were found interbreeding in all combinations. A large number of specimens of A. vitis were kindly sent to us by Professor Valery Mayet of Montpellier, France, and they appeared to be identical with the brown form occur- ring here. He also sent us two specimens of A. obscurus, saying that these were very rare and never found on the vine, as noted above. They were slightly larger than the black form occurring on the vine here. On account of the great difference in food plants it would appear that the obscunts of France is a distinct species from that of vitis; but an inquiry into the geographical distribution of the two forms seems to indicate that it is simply a case of a dichromatic species, with one or the other of the two forms predominating in the different regions, with the exception of the California vineyards, where both forms occur in about equal numbers. On account of priority the correct specific name should be obscurus Linn, representing the black form, while vitis F. should be applied to the bi colored variety. In France this insect goes by the common name of Le Gribouri or Ecrivain, the scrawler or writer; but since these names are hardly 1 Des Insectes, 1G02. 2 Insectes de la Vigne, p. 322, 1890. 3 Amer. Entomol. Soc., vol. 19, p. 196. 4 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. applicable in this country and because of the possible confusion with the engraver beetles, it does not seem desirable to adopt either of these as a common name for the insect. Cooke gave it the name of "Imported Grape Flea-beetle"; but since it is not a flea-beetle at all, this name is not warranted. Since the life history and habits of this species are almost identical with those of the Grape Root-worm (Fidia viticida Walsh) of the Eastern States, and the fact that it is, thus far at least, a grape pest in this country only in California, we have given it the common name of California Grape Root-worm. Distribution. According to Dr. Horn 1 the obscurus or black form occurs most abundantly in California and Nevada and one specimen has been noted from Colorado. The vitis form extends from New Hamp- shire westward to the Lake Superior region, Utah, Colorado, and Wash- ington, only a few specimens coming from the last three localities. Dr. Hamilton in his catalogue mentions Adoxus vitis as "widely dis- tributed across the northern part of the continent, extending north on Mount Washington, N. H., to the Hudson Bay region, westward to California and south to New Mexico; and southward in the Atlantic States through New York." A. L. Melander, entomologist of the Washington Station, states that there is but a single specimen in their collection taken in the Grand Coulee in 1892. Professor Cordley of the Oregon Station writes that he has no record of its .occurring in that state on the grape, nor has Professor Aldrich any record of its occur- rence in Idaho. Through the kindness of A. L. Quaintance of the Bureau of Ento- mology, Washington, we are able to give the localities of obscurus and vitis occurring in the National Museum Collection, as follows: Mount Adams and Mount Washington, N. H. ; Marquette and Port Huron, Mich.; numerous specimens from New York and New Jersey; Isle Royal and Michipicoten Bay, Lake Superior; Colorado Springs, Veta Pass, Elk Park, and Garland, Colorado ; Bear Paw Mountain, Mont. ; Park City and Alta, Utah ; Kaslo and Bear Lake, B. C. ; Easton, Washington; Portland, Oregon; Placer, Alameda, Los Angeles, and Sonoma, California ; and Bulah, New Mexico. We are indebted to Dr. E. C. Van Dyke, of the California Academy of Sciences, for some interesting facts on the distribution of Adoxus, from whom we quote as follows: "The various species of its native food plant, Epilobium, is widely distributed over the northern parts of Europe, Asia and North America. On the Pacific Slope the beetle is found in all of the lowlands of western Washington and the northern half of western Oregon and extends south along the Cascades (here up to near the timber line, some specimens being taken at an elevation of 10,000 feet on the snow fields of Mount Rainier) ; along the Sierras to 1 Trans. Amer. Entomol. Soc., XIX, p. 198, 1892. BULLETIN 195. CALIFORNIA GRAPE ROOT- WORM. 5 at least as far south as Tulare County, California. This region, includ- ing also the Eastern States, with the exception of the Sierras in Cali- fornia, is occupied by the bicolored variety vitis F. The melanotic form or true obscurus L. has been found besides in California, in Colorado, and one specimen, among many thousands of the variety vitis F., at Port Angeles, Washington. ' ' The insect is found throughout Siberia, where in the Amoor region and around Lake Baikal, the true obscurus L. according to the cata- logue of L. Von Hey den, which clearly differentiates the two forms is the dominant one, and perhaps as much a race there as it is here. In west Siberia the variety vitis F. seems to be the predominant one. This peculiarity of distribution is in keeping with that of many of the other species of beetles that are common to both continents, the eastern specimens related to the more western of those of the old world, while ours are more closely related to those of the highlands of southeastern Siberia, etc., the so-called Japano-Manchurian region." It appears then that the obscurus form living upon its native food plant in the Sierra Nevada mountains has transferred itself to the vine- yards, but here instead of obscurus occurring exclusively, both obscurus and vitis occur in about equal numbers. The points at which the beetles were reported as injurious this year from Merced to Marysville, parallel with the Sierras, points strongly to the fact that it has come down from the mountains and established itself in the vineyards of the valley. The beetles also occur in the Sonoma Valley, and this may be accounted for by the fact that its native food plant is also found here. According to Jepson, 1 the fire weed (Epilobium spicatum) has been collected in western and middle California only in Sonoma County, near Guerne- ville. The distribution of this insect, with its varying color forms in the different regions and its apparent transfer to cultivated plants, present an interesting biological problem. As an economic species it is widely distributed in Europe, occurring particularly in the vineyard sections of France, Italy, and Algeria. Here in the United States it seems to have gained its strongest foothold in California. According to Cooke it was reported from six of the principal grape sections of the State as far back as 1882. Within the last two or three years it has been most abundant in the Sacramento and San Joaquin valleys, and in the coast region near Sebastopol and Healdsburg. Related Species. In the Eastern States, particularly in the grape growing sections of Ohio and the Chautauqua belt of New York, there is a similar insect called the grape root- worm (Fidia viticida Walsh) that does very serious injury to the vineyards. This insect has been 1 Flora of Western and Middle California, p. 329. 6 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. known to occur in New York since 1866, and has been a pest on the vines there since about 1893. This insect in all essential respects, so far as habits go, is similar to the one treated of in this bulletin. It is also closely related entomolog- ically, both being members of the same group (Emolpini) . The common Diabrotica, the flea-beetles, the asparagus beetle, and numerous other leaf eating beetles belong to this same family. Economic Importance. While the insect has occurred on vines in the State for the last thirty years it seems not to have spread so > rapidly as might have been expected, judging from the experience with the same insect in Europe and its related species in the Eastern States. It is difficult to explain just what may account for this. Since the greater part of the insect's life is spent in the ground, it is in this stage that conditions would be most likely to influence its progress. Such conditions might be found ' in the kind of soil, the cultivation of the soil, the variety of vines and the great depth of the root systems in some of our drier sections. Again, the true importance of the insect's work has never been appreciated in the State hitherto, since it has been known as a leaf feeder entirely. Vines, therefore, may have shown a general unthriftiness due to its attacks, but because the root infesting habits of the larvse were unknown the trouble may have been assigned to other causes. However, during the present season in the neighborhood of Lodi, we have good evidence of what injury the insect may bring about. In the particular vineyard where our studies were made, it had been noticed that something was wrong with the vines, but just what it was had not been determined. During the past winter two or three acres of the vines which were worst affected were dug up. The piece adjoin- ing where these vines were uprooted was badly infested during the past spring with a beetle with which the .owner (who came into posses- sion of the property a year ago) was unfamiliar. The matter was reported to us and upon investigations it was found to be the root beetle. The beetles were very abundant over a narrow strip in the center of the vireyard and had already done considerable injury to the leaves and other growing parts of the vines. The men who pruned the vineyard in the winter noticed that this strip of vines had not made the growth that was made by the vires on either side. Fortunately the old stumps and roots which had been dug up had been saved for fuel, and upon examination were found to be badly gnawed by this insect. Some of the vines in the strip where the beetles were abundant this year made practically no growth until late in the season. The beetles were nearly all killed on this area this year, and hence the vines became free from the larvae and started their growth very late. On another vineyard BULLETIN 195. CALIFORNIA GRAPE ROOT- WORM. 7 near Lodi these beetles have been very numerous for two or three years, and the owner estimated that his crop had been reduced from one third to one half. These two instances are comparable with what has occurred over a considerable area in the Eastern States on account of the presence of the other species there. Our species has been observed in several vineyards, and doing consid- erable damage in 1908 where they were not seen at all in 1907. This may be partly accounted for through the excessive rain in the spring of 1907 causing their temporary disappearance, but there is no doubt that the insect is becoming more widely distributed. The station has also received more inquiries about the insect than usual during the season just passed. The attacks of this beetle have been credited with being the cause of the sunburn of the Tokay grape. The theory of those who support this view is that the gnawing of the beetles on the stalks, pedicels and berries "poisons the sap" or injures the bunch mechanically, and thus induces the drying and shriveling of the berries. The experiments and observations of Messrs. 0. Butler and B. J. Wingfield, at Florin in 1905, indicate that the above-ground attacks of the beetle have little or nothing to do with causing sunburn unless, of course, there is more or less actual defoliation. Besides exposure, sunburn seems to be due to several causes, tending to diminish the vigor of the vine, and probably the underground attacks of the beetle larvae are among the most serious of these weakening causes. The Soil It Infests. The typical soil in the Tokay grape section about Lodi is a sandy loam. It is in such soil that the vineyards mentioned above are located. In another vineyard, however, near Stockton, beetles were present in considerable numbers in the black adobe soil character- istic of that region. About Florin, where the soil is clayey, the insect is also troublesome. Dr. Felt 1 in speaking of the eastern root-worm's preference for soil says: "The depredations of this pest are much worse and usually first apparent in light, sandy or poor soils, and in particular on gravelly knolls. The insects seem to thrive under such conditions and a defi- cient growth should lead to immediate investigation. Vines on rich clay soils in our experience sustain comparatively little injury from this pest, and this appears to be the case in Ohio. ' ' Preference for Varieties. With a view to determining whether or not seme varieties are resistant to the attacks of the eastern species, the Cornell Experiment Station secured roots of several types of Ameri- can vines, and after grafting them on to the standard varieties grown there, distributed them in the infested districts. The work is still in the experimental stage, but it may be promising as a line of possible 1 New York State Museum Bulletin 59. 8 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. control for such a root infesting insect. In the same bulletin it is stated that some large vines of a ' ' native type ' ' growing along a fence within a few feet of a badly infested Concord vineyard suffered no injury, not even the leaves being eaten by the beetles. Our own observations on the matter of resistant varieties for the root- worm in California have not been extensive enough to warrant drawing any conclusions. The infested vineyards at Lodi are of tlje Tokay and Zinfandel varieties, but since these are the principal grapes grown here, it proves nothing. In other sections many different varieties of vines are subject to attacks by this insect. APPEARANCE AND DESCRIPTION OF THE STAGES. The Egg. The eggs of this beetle are small yellowish white objects FIG. 1. A cluster of eggs as they are found naturally on the bark (enlarged). FIG. 2. A single egg highly magnified. which may be found in clusters (Fig. 1) under the old bark of the vine. An individual egg (Fig. 2) is about one twenty-fifth of an inch long and somewhat cylindrical in shape, being about one third as broad as long. The Larva. The full grown larvae vary considerably in size, but the larger number will measure a little more than a quarter of an inch, as they are found naturally in a slightly curved position. When they are straightened out they measure seven twentieths to eight twentieths of an inch. They are white in color, excepting the head, which is yellow- ish brown,, with the mouth parts dark brown or black. The arrangement of hairs is as shown in figure 3. The spiracles are indicated by a yellow- BULLETIN 195. CALIFORNIA GRAPE ROOT-WORM. ish spot or ring and are easily visible. The proximal joint of the labial palpus is as long as the other four. The antennae are short and incon- spicuous, consisting of three joints and ending in a couple of peg-like processes and two small spines. The legs are covered with hairs or setaa similar to those on the body. The claws are long, slightly curved, and dark brown in color. FIG. 3. Larva. The Pupa. The pupa (Figs. 4 and 5) is about one fourth of an inch long and about the same length across the extended wing pads. The color is pure white, the hairs or spines alone being colored brown. On the head near the prothorax, extending trans- versely, is a row of four spines, and behind this row are four spines, slightly smaller, arranged in the form of a quadrangle. On the dorsal side of the abdomen are transverse rows of delicate hairs. The anterior and hind femora are armed with a stout spine. On the hind femora there are also two stout bristles. The anal hooks are very stout and broad at the base, ending in a sharp spine, curved upward and tipped with black. Just anterior to the anal hooks on the dorsal side is a row of four short blunt spine- like tubercles, each ending in a bristle. On the next anterior segment is a row or six spines. These are longer and stouter than those on the other segment, but end in a similar sharp bristle. There are two pairs arranged on either side FIG. 4. Pupa. Dorsal view. 10 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. of the dorsal line, and below these laterally is a similar single spine. There are also hairs or bristles extending farther laterally. The Beetle. There are two forms of the adult beetle oc- curring in the State, one being black in color and the other mostly brown. There is consider- able difference in the size of different specimens, and par- ticularly in the sexes the males being much smaller. On an average they will measure about one fifth of an inch in length. The black form FIG. 5. Pupa. Ventral view. (AdoxUS Linn.) is almost wholly black in color. The antennas, tibia and tarsi, however, in some specimens merge into dark brown. The entire body, as well as the appendages, are cov- ered with a pubes- cence 'of short gray hairs. The brown form (Adoxus vitis Fab.) has the elytra, tibia and basal half of the antennae brown, while the remaining parts are black. It is covered " with a FIG. 6. Adult of the grape root- worm. gray pubescence as is the other form. The head in both is capable of being well retracted into the prothorax. Both forms of the beetle are about equally distributed, and interbred indiscriminately. BULLETIN 195. CALIFORNIA GRAPE ROOT-WORM. 11 LIFE HISTORY AND HABITS. The Egg. The eggs of this beetle are laid usually in crevices beneath the inner layers of bark on the old wood. They are not confined to last year's wood, as seems to be the case with its eastern ally, but are laid anywhere on the stump of the vine above four or five inches from the ground. ' "With the California system of pruning, there is of course little of last year's wood left on the vine, and the bark on this is too smooth to offer the most suitable situations for egg laying. Indeed, during the past season we found no eggs on last year's wood, but all on the older part of the stump, which was covered with two or three layers of old bark. In some cases, where the bark was in close contact with the wood, it was hard to explain how the beetle got beneath the two or three layers to deposit its eggs. In nearly every case they were certainly well protected from most enemies and out of reach of any spray. The eggs are laid in clusters of from four or five to twenty-five or thirty; usually where the smaller numbers were found the crevice in which they were deposited would not furnish room for a larger number. Where there was plenty of space the number ranged from a dozen to thirty. The most common numbers counted in the many clusters exam- ined ranged from ten to twenty. The eggs in the cluster may be irregularly arranged or somewhat in the form of a concentric ring, the particular arrangement depending probably upon the space in which they are deposited. Where there was plenty of room the eggs were sometimes well scattered, extending over a diameter of a quarter of an inch or more. In other cases a pretty well defined concentric arrangement was found. Occasionally, a small crevice would be found with but two or three eggs. Number. The largest number we succeeded in .getting a single female to lay in our breeding cages was seventy-nine. These were laid, at three different intervals, extending over a period of about one month. Others laid but a single cluster of from fourteen to twenty and then died. The same insect in France, according to Mayet, 1 lays in the neighborhood of thirty eggs either singly or in patches on the under side of the leaves. This number is probably simply an approximation. The fact, if it is a common occurrence, that they are laid on the under side of the leaves, is the most striking difference between the habits in California and in France. We have had some eggs laid on leaves in our breeding cages when there' was nothing else for them to oviposit on, but we never found any indication of this habit in the field. From our breeding cage experiments and field observations we are 1 Insectes de la Vigne, p. 308. 12 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. inclined to think that few, if any, deposit more than three or possibly four clusters, making a total of not to exceed one hundred, or possibly, one hundred and twenty eggs. From fifty to seventy-five will be nearer the average. The majority of the beetles in our cages laid but a single cluster of twenty or twenty-five, but those were under slightly un- natural conditions where there was not a constant supply of fresh food. A number of females were dissected to determine the number of eggs in the ovaries, and these varied from sixteen to twenty-four well developed eggs. The eggs of a cluster are very slightly glued together with a sticky material. By careful handling it is possible sometimes to take these off en masse, but the majority of clusters will fall apart upon the slightest handling. The eggs of the eastern species are said to be covered with a gummy material which holds the entire mass securely together, but with this species we failed to find any that would withstand any very rough handling or which could be blown off the vine in clusters by the wind. Time Required to Hatch. In our breeding cages the shortest time required to hatch was eight days, and the longest period twelve days. This was under conditions which varied but little FIG. 7. Larva of the California grape root- from that of the vineyard, the temperature being lower, if in any way different, especially in the forenoon, since the laboratory had a west exposure away from the morning sun. A large number of eggs were thus timed for the incubation period and they all came within the limits stated above. This, of course, may vary in warmer or colder weather, but from ten to twelve days may be taken as the average hatching period. The eggs of the same cluster were all observed to hatch within one day. The Larva. The young larva upon hatching from the egg makes its way to the ground almost immediately. It may crawl to the ground, as we infer from finding them pretty well scattered down the trunk of the vine, or they may possibly in many cases simply drop to the ground, though this was not actually observed. This seems to be a common habit with the eastern species, but here in California with the short-pruned vines, and consequent nearness to the ground, we believe that most of the larva? crawl down the trunk. Young larva? kept under observation in a test tube filled with compacted soil, wan- BULLETIN 195. CALIFORNIA GRAPE ROOT- WORM. 13 dered about looking for a suitable place for entering the earth three or four hours before they actually disappeared. By the following morning they had gone about halfway down the tube, or three inches, FIG. 8. Root of a vine with bark eaten off by root-worm. and before the end of the same day they had burrowed through the six inches of soil in the tube. As soon as the larvae reach the roots of the vine they begin feed- ing, and it is generally the smaller rootlets that are first attacked, FIG. 9. Stem leaf and fruit eaten by root beetle. although we have found young larvae around roots of considerable size. These smaller roots may be eaten off entirely. The larger roots are injured by the larvae gouging out long strips of the bark, which some- times take almost any direction, but on the roots of medium size these 14 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION. strips are usually eaten out in a direction parallel with the axis of the root, or in a spiral direction. The "frass" or eaten bark is left in their paths and is characteristic of their injury. The furrows made are from one tenth to one fifth of an inch wide, and in cases of severe injury all the bark may be eaten away from the roots. This feeding is continued from the time they hatch in the spring until the vine becomes dormant in the fall. By September 1st some of the larvae were found nearly full grown, while others were not more FIG. 10. Grape leaf showing characteristic work of the beetle. than half grown. In the case of the latter, their growth is completed by feeding during the following spring, which accounts for some of the larvae being found as late as the last of May. The first observed appear- ance of the young larvae in the Lodi section in 1907 was on May 30th, this being about a month after the first appearance of the beetles. The larvae were found as far down as two and a half feet, and no doubt go farther than this, since in some of the vines there were no roots to speak of nearer than a couple of feet from the surface. The larvae were found within a radius of fifteen inches from the main central root, and no doubt the majority occur within a radius of a couple of BULLETIN 195. CALIFORNIA GRAPE ROOT- WORM. 15 feet. They apparently remain dormant during the winter season, changing to pupae the following spring. Some full grown larvae of the preceding year were found about the roots as late as May 29th during 1907. The Pupa. The full grown larva which has wintered over in the ground changes to the pupa in the early spring. The larvae upon reach- ing maturity ascend toward the surface for pupation. The pupae taken this past season were found at a depth vary- ing from four to eight inches below the sur- face. The depth de- pends somewhat upon the amount of mois- ture near the surface. Those found nearer the surface were taken from where there was considerable moisture to within two or three inches from the sur- face. The pupae, being covered with a delicate white skin, require a fairly moist soil to pre- vent them from drying or shriveling up. We met with this difficulty of drying with some of the pupae taken to the laboratory. About two weeks is required for the devel- opment of the insect in the pupa stage. The first adult beetles seen in 1907 and 1.908 were dis- covered about May 1st, so that pupation must have begun about the middle of April. The insect may, however, remain in the pupa stage for a month or more. The pupa simply rests in a little cell hollowed out by the larva, and any disturbance of the earth is very likely to break this cell and expose the pupa, which on account of its delicate structure will usually succumb to such treatment. 2 BULL. 195 FIG. 11. Tip of a shoot, with the leaves, stem, petioles and pedicels attacked by the root beetle. 16 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. The Beetle. The adult beetle, into which the pupa in its cell in the ground transforms, emerges from the ground and begins to attack the growing parts of the vine above ground. For the greater part of the season the insect has been a root feeder, but having completed its early stages underground, it comes to the surface to feed for a brief time, to lay its eggs, and then dies. The beetle as it comes from the ground is somewhat lighter in color, but upon exposure to sun and light its chitinous covering soon becomes darker in color and more rigid in texture. The time of ap- pearance of the first beetles during the years 1907 and 1908 at Lodi was May 1st. They may con- tinue to emerge until June 1st and possibly later, al- though the greater number of the beetles came out in 1907 and 1908 during the first half of May. It has been stated that a few larvae and pupae were taken on May 29th, which would indicate that a few belated beetles may not appear before the middle of June. FIG. 12. A cluster of grapes badly gnawed by the root beetle. The beetles were most numerous on the vines this season about the middle of May. In the latter part of May they begin to disappear and by the last of June are practically all gone. The beetles soon begin their work on the vine by feeding upon the leaves. They are nearly always found on the upper surface. In feed- ing they eat out chain-like strips from the leaves (Fig. 10), these slits being about one twentieth of an inch wide and from a quarter to three quarters of an inch long. Sometimes the framework of the tissues is left, making a skeletonized effect, though often the entire substance is BULLETIN 195. eaten away. This gives the leaf a lace-like effect, the parts left in cases of bad injury be- ing held together by mere threads. The beetle also gouges out strips of the bark of the tender shoots in the same manner as it works on the leaves (Fig. 11). Sometimes the shoot is thus gouged out all the way around and turns brown in color. This loss of bark or covering interferes consid- erably with the conveyance of nourishment to the fruit and growing tip. The petioles of the leaf are similarly attacked, as are also the pedicels of the berry ; and the pedicels being of a small size, a few gougings around them will cause the berry to dry up. The berry itself does not escape the attacks of this beetle, and in July berries may be seen that are cracked CALIFORNIA GRAPE ROOT- WORM. 17 t ft f t t t FIG. 13. The work of the beetle on the berries. FIG. 14. A vine stunted in growth through injury to the roots by the California grape root-worm. Photographed June 6, 1907. 18 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. open or gouged out on one side (Figs. 12, 13), and the growth inter- fered with as a result of an attack of these beetles in May or June. The beetles may continue to feed for a month or more. After feeding a couple of weeks egg laying begins, and this takes place at intervals of a week or two, when the clusters of eggs are deposited as already indicated. The beetles are very easily jarred from the vine upon the slightest disturbance, and fall to the ground "playing 'possum" and remain quiet for a short time, but soon become active again when left undis- turbed. This habit of readily dropping to the ground offers a means of controlling the insect in this stage. The beetles fly around but little, and will usually be found in the immediate vicinity in which they emerged. The vineyards which were under observation showed that the great bulk of the beetles were confined to a comparatively small area, and reports from the owners indicated that they had been present in these spots for several years. In the case of some vineyards, according to statements made by the owners, these beetles have been present for a good many years. In such cases as these there seems to have been some factor in keeping them from becoming excessive and destroying the vines. In one vine- yard near Lodi, where the beetles are said to have been present for many years, they have become especially abundant only during the last year or two. During this period they have also spread more rapidly, and since it has become known that they feed upon the roots as well as the leaves the growers have begun to realize their importance, and remedial measures will be undertaken against the insects. CONTROL MEASURES. Natural. Probably the most important factor in the way of climatic control of this insect would be unusual rainfall during the winter season. During the winter of 1907, which was a very exceptional one, large areas were covered with water which hitherto were unknown to have been flooded. Where this exceptional amount of moisture pre- vailed and vineyards were covered for a couple of weeks, there were very few beetles during the following season. Except in one or two cases, however, we were not aware of the fact that beetles had occurred in those situations in previous years. But they were, nevertheless, present again in 1908. Aside from excessive moisture in the soil, there is little in the way of climatic control that will aid in the fight against the insect, unless it would be in some condition that would be conducive to the development of a fungus affecting the adult beetle. In our interior California weather, however, of May and June there is little hope of anything BULLETIN 195. CALIFORNIA GRAPE ROOT-WORM. 19 very effective appearing as dependent primarily upon moist weather. The fact that the eggs of this beetle are very securely hidden away beneath one or more layers of bark affords little opportunity for them to be attacked in any large manner by parasitic or predatory insects. The young larva is for a brief period (from the time of hatching until it enters the ground) more or less exposed to the attacks of enemies, but the interval is generally too short to allow of very great destruction. Once in the ground where it remains for the greater part of the year it is pretty safe from most enemies. About the only thing likely to attack the larva here would be the predaceous ground beetles. None of these were actually observed attacking them during the past two years. The larva is usually so deep in the ground as to be out of reach of most natural enemies. The pupa comes nearer to the surface and is hence more liable to attack. It is probably in this stage that the greatest mortality occurs, both from enemies arid from cultivation of the soil and other opera- tions by man. In the adult or beetle stage, the insect is directly exposed and is likely to be attacked by a large number of enemies, including insects and birds. ARTIFICIAL CONTROL. Of the Egg. Since the eggs are secreted under one or more layers of bark, there is little possibility of any spray or wash reaching them. On account of their small size and the difficulty of finding the clus- ters, hand . picking is out of the question. Those who believe in stripping off the old bark and spraying with bluestone during the dormant season, with the primary object of preventing black knot, will, incidentally, inconvenience these beetles by doing away with the more favorable situations for egg laying. This, however, can not be counted upon as very effective in controlling the beetle. The eggs will be deposited in spite of this treatment, and freeing the vines from their loose bark will result simply in rendering the eggs a little more exposed to the attack of enemies. Of the Larva. The matter of controlling any underground insect is a difficult problem, and the larva of this beetle is no exception to the general rule. Various remedies and schemes have been tested for accomplishing this work, but the greater number of them have been abandoned. The problem, therefore, is now limited largely to control by resistant stock, cultivation, crop rotation, or other regular farm practices; but, with an insect such as this, that spends a portion of its existence above ground, it is not necessary to control it in the larval stage, since it can be more easily and effectively done in a later stage. It was suggested by some of the growers that something might be 20 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. applied to the ground to prevent the larvae from entering, but knowing the results of the New York experiments 1 along this line, we gave little encouragement to the idea, and did not repeat the experiments. Kerosene emulsion and crude petroleum were used in New York, but neither proved of any practical value. The trouble with such sub- stances is that they are too readily absorbed by the dry soil and too quickly evaporated. Our California crude oil, which has an asphaltum base (instead of paraffine, as is the case with eastern oils), would not disappear so quickly, but few farmers would want such a substance mixed with their soil. FIG. 15. At work digging out larvse of the California grape root-worm'two and one half feet beneath the surface. Of the Pupa. As heretofore stated, the pupa? are found at a depth of from four to eight inches below the surface. This, together with the fact that any disturbance of the cell in which they are resting will generally prove fatal, offers a chance of doing something in the way of control while in this stage. While some of them are beyond the depth of the plow as ordinarily used about the vine, yet probably the major- ity will be found within about six inches from the surface. They do not come up to the dry soil to pupate, but remain just below it. If a shallow mulch of two or three inches can be kept immediately around the vines until the insects are ready to pupate, this will conserve the -1 New York State Museum Bulletin 59, p. 77. BULLETIN 195. CALIFORNIA GRAPE ROOT-WORM. 21 moisture just below the mulch and encourage the larvae to come nearer the surface to transform to the pupae. If then, at the proper time, just before the beetles begin to emerge, the soil, about the vine is stirred to a depth of about six inches, no doubt a large percentage of them will be destroyed. Another point, and one which makes the problem more difficult, is that the pupae do not all appear at once, but may be found for a month or more. This may make it necessary to go over the ground more than once. However, probably the majority of the beetles emerge at about the same time in the early part of the season, and, if measures are taken against the pupae just preceding the emergence, large numbers of them will be destroyed. If more than one cultivation FIG. 16. Vines enclosed with mosquito netting to determine if beetles will emerge through uncultivated soil. is undertaken they should be done at intervals not to exceed two weeks, since the pupae will complete their development within this period. This matter of deep cultivation for two or three feet around the vine, while not expected to completely control the insect, will, never- theless, aid in its control. It is, of course, of no use unless done at the proper time when the insect is in the pupal stage. The proper time for such cultivation during the past two years at Lodi would have been during the last of April, but this may vary with the season and locality. It is possible that in some soils the destruction of the beetles before they emerge from the ground may be accomplished in another way. In making some experiments at Florin, in 1905, for the determination of the causes of the sunburn of Tokay grapes, Mr. B. J. Wingfield 22 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. found that the beetles were unable to force their way out of the ground when it was covered with a hard, uncultivated crust, such as is left after rain on clayey soils. Each of six vines was covered on May 4th with a cage of mosquito netting. In three of these cases the netting was tied tightly around the lower part of the stem, as shown in figure 16, in order to prevent the possibility of any beetles getting on to the above-ground portion of the vine. In the other three cases the netting was brought down to the ground, enclosing about three square feet of soil surface in- side the cage, as also shown in figure 16. This enclosed surface remained unculti- vated until about the middle of July, when the cages were re- moved. No beetles were found at any time on any of the six enclosed vines, and no signs of their attacks on leaves, fruit or other above- ground portions. This is easily ex- plained in the case of the vines which were com- FIG. 17. A single vine as shown in figure 16. pletely shielded from attack by tying the netting around the stump ; but in the case of the other vines which were exposed to any beetles which might emerge from the soil within eighteen inches from the stump, the only explanation seems to be that the beetles were unable to force their way through the compacted surface crust. That the pupa^ and beetles were abundant in the ground was shown by the fact that all the uncovered vines next to those which were covered were badly infested by the beetles and showed abundant evidences of their attack on all parts. BULLETIN 195. CALIFORNIA GRAPE ROOT-WORM. 23 The effectiveness of a method based on this experiment would depend largely on the type of soil. Only a soil that will form a hard, com- pact surface layer could be utilized according to this plan. We do not know how it would appeal to the growers to leave three or four feet about the vine uncultivated until about the middle of May or possibly later, as would be necessary in this case ; but if the beetles were present in large numbers and this controlled them, it would pay amply. Again, showers of rain that are apt to come as late as the mid- dle of May would soften the soil and militate against the method. Spraying. The adult or beetle eats away portions of the leaf or gouges- out strips of the surface of the shoots and other growing parts, so that a poison applied to the vine will be consumed by it in this opera- tion. The most serious drawback to poisoning is the fact that beetles are pretty resistant to poisons, and considerable amounts must be con- sumed before the insects are killed. However, if a strong arsenical spray is thoroughly applied at the beginning of the attack it will prove to be fairly successful. In the experiments this season the beetles were killed in from two to three days on leaves thoroughly sprayed with lead arsenate in the ratio of five pounds to fifty gallons of water. One pound of paris green to seventy-five gallons of water also gave good results. In the case of paris green a few vines should be used as a test to determine the maximum amount that is safe for the foliage, since there is danger of burning if used too strong. It is not a very difficult matter to spray the short-pruned California vine during the last of April or the first of May, and thorough work 1 can be done at this time. The spray should be applied mostly from above, since it is on the upper surface of the leaves and shoots that most of the feeding is done. Jarring. Since the beetle is very readily jarred from the vine, this offers one of the most satisfactory means of controlling the insect. Generally it is only those that are in a cup-shaped leaf, or in a grape cluster, or in some part of the old wood, that will not be disturbed by a reasonable jarring. This method has the advantage of killing the beetles directly, before egg laying is commenced, which may not always be done by means of the poison spray. The worst objection to the method is that the beetles may keep emerging from the ground for three or four weeks, making more than one treatment necessary. Fortunately, however, these attacks are generally confined to a limited portion of the vineyard, so that the problem is not so difficult as it would be were it necessary to go over the entire area. 24 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. The sort of apparatus which was used successfully on a badly in- fested vineyard near Lodi this year was the vine-hopper cage shown in figure 18. This device was constructed for capturing the vine hopper, and when a nearby vineyard became infested with the beetles it was used against them. This cage consists of .an ordinary mosquito netting tacked over a square framework of laths or some other light material. The essential part of it so far as the beetles are concerned is the tray at the bottom. This is made of a sheet of galvanized iron turned up about an inch at the edges. The crude oil which is placed in this tray is fatal to all insects falling into it. The V-shaped opening in the tray permits the cage to be pushed on to the vine, which is bumped at the same time and the beetles jarred off. A pad- ding of leather is tacked on the base of the open- ing in front of the vine. The opening may be closed by tacking two strips of can- vas, one on each side, so as to meet in the center. These strips are sup- ported by transverse pieces of three-quarter inch rubber tubing, which are sewed on to the canvas beneath. This rubber tubing supports the canvas over the opening, and when the cages are placed in position it gives way for the base of the vine, but immediately springs back again through the flexibility of the rubber. Steel strips will answer the same purpose, but the rubber is described because it is cheaper and more easily obtained. This cage has the advantage of catching the vine hopper, which is likely to be present, with the same operation. For the beetle alone, simply the tray at the bottom may be used, or the sides extended up FIG. 18. A cage used to capture the beetles on the vine. BULLETIN 195. CALIFORNIA GRAPE ROOT- WORM. 25 and slightly outward with wire netting or canvas, to get those that may be on the outer parts of the vine. Handles may be attached to this, so that it can be manipulated without stooping. Such a cage can go over four or five acres a day, and there is little outlay save the time of the men doing the work. Since the beetles, if taken in time, are dis- tributed over a comparatively small portion of the vineyard, it means but a day's work or two. This, then, can be repeated three or four times, if necessary, without much expense, and the vines saved from any further ravages of the pest. SUMMARY. This insect has been a destructive enemy of the vine in Europe for many years, and for several years past it has been doing considerable damage to the grape in California. A related native species is an important pest of the vines in the East. It attacks both the roots and the growing parts of the vine above ground. From June to May the insect is in its larval and pupal stages underground. During May and June it works on the parts of the vine above ground as a beetle. Many of the pupa? may be destroyed by deep cultivation for a radius of two or three feet about the base of the vine. The beetles may be killed by a strong arsenical spray, or by jarring into crude oil, or otherwise captured as they are shaken from the vine. 26 PUBLICATIONS. BIBLIOGRAPHY. 1(502. Aldroyandi, De Insectes. 1732. Pluchi, Spectacle de nature, Paris. 1764. Geoffrey, Histoire abregee des Insectes des environs de Paris. 1804. Latrielle, Histoire naturelle generate et particuliere des Crustaces et des Insectes (Paris Hist. Ins. 1804, 11, p. 331). 1819. Latrielle, Nouveau Diet. d'Histoire Nat. 1828. Touchey, Bull. Soc. Agr., Herault, p. 5. 1836. Westwood, J. O. Westwood on Insects, vi, p. 247. 1836. Walckener, Ann. de la Soc. Ent. de Fr., iv, p. 687 et seq. 1841. Vallot. Histoire des Insectes Ennemies de la Vigne. 1842. Audouin, Insectes Ennemies de la Vigne. 1846. Guerin-Meneville, Ann. Soc. Ent. Fr., 1846, Ser. 2. T. 4, Bull. p. 35. 1849. Demermety, Quelques faits sur 1'Ecrivain, Jour. d'Agr. de Dijon. 1862. Guerin-Meneville, Rev. Mag. Zool., 14, pp. 360-4. 1864. Baron Thenard, Comtes Rendus Acad. Sci., 6 Novembre, Vinas, Le Gribouri (Revue viticole de Dijon). 1873. Horvath, Beitrag zur Naturgeschicte von Emolpus vitis, Ann. de la Soc. Imp. Roy. Zool. Bot. de Vienne. 1874. Lichenstein, Ann. Soc. Ent. Fr., Ser. 5, T. iv. Bull. p. 228. 1874. Girard, Maurice, Ann. Soc. Ent. Fr., Ser. , T. iv, Bull. pp. 63 et 140. 1876. Lichenstein, Ann. Soc. Ent. Fr., Ser. 5. T. v. Bull. p. 105. 1876. Arviset, Bull. Insectol Agric., Paris, T. i, p. 182. 1876. Rendu, V., Les Insectes Nuisibles A FAgriculture, pp. 106-107. 1876. Perris, Ann. Fr., vol. 6, pp. 216-217. 1878. Valery Mayet et Lichtenstein, Etude sur le Gribouri, Ann. Societe des Agr. de France and Ann. Societe d'Horticulture et d'Histoire nat. de 1' Herault. 1879. Lichenstein, Etudes sur le Gribouri ou 6crivain de la Vigne, Montpellier, p. 12. 1880. Pacific Rural Press, May 29. 1881. Jobert, C. R., Acad. Sci., Paris, T. 93, pp. 975-7, Jour. R. Microsc., Ser. 2, vol. ii, pp. 1-39. 1882. Cooke, Matthew, Injurious Insects of the Orchard and Vineyard, p. 194. 1883. Kittel, Correspbl. Zool. Min. Ver., Regensburg, 37, p. 157. 1887. Andre, Metamorphosis de 1'Eumolpus vitis. Le Naturaliste, Paris, pp. 96-98. 1887. Oliver, E., Ann. Soc. Ent. Fr. 1887, Ser. vi, T. 7, p. 128. 1889. Le Progres Agricole, x, No. 37, pp. 576-8. 1890. Mayet, Les Insectes de la Vigne, p. 321. 1890. Ricksecker. L. E., Orchard and Farm, June, p. 59. 1891. Montillot, Louis, Les Insectes Nuisibles, pp. 114-6. 1891. Craw, Alexander, Destructive Insects. 1891. Riley and Howard, Insect Life, vol. iii, pp. 298 and 349. 1892. Horn, Dr. Geo., American Entomological Society, vol. 19, p. 196. 1893. Rupertsburger, Wein. Ent. Zeit, xii, p. 215. 1896. Sajo, K. Selus, Wochenschr. Ent., i, No. 32, p. 501. 1897. Sajo. K. Selus, Wochenschr. Ent., ii, No. 9, pp. 129-34. 1897. Coste. Floret P.. Progres Agricole et Viticole, Nos. 30, 32, and 33. 1908. Quayle, H. J., Jour. EC. Ent., vol. i, No. 3, p. 175. PUBLICATIONS. 27 STATION PUBLICATIONS AVAILABLE FOR DISTRIBUTION. REPORTS. 189G. Report of the Viticulture! Work during the seasons 1887-93, with data regarding the Vintages of 1894-95. 3897. Resistant Vines, their Selection, Adaptation, and Grafting. Appendix to Viticultural Report for 1890. 1898. Partial Report of Work of Agricultural Experiment Station for the years 1S.r,-nr, and 1890-97. 1900. Report of the Agricultural Experiment Station for the year 1897-98. 1902. Report of the Agricultural Experiment Station for 1898-1901. 1903. Report of the Agricultural Experiment Station for 1901-1903. 1904. Twenty-second Report of the Agricultural Experiment Station for 1903-1904. TECHNICAL BULLETINS ENTOMOLOGICAL SERIES. Vol. 1, No. 1 Wing Veins of Insects. No. 2 Catalogue of the Ephydridse. BULLETINS. Reprint. Endurance of Drought in Soils of the Arid Region. No. 128. Nature, Value and Utilization of Alkali Lands, and Tolerance of Alkali. (Revised and Reprint, 1905.) 133. Tolerance of Alkali by Various Cultures. 140. Lands of the Colorado Delta in Salton Basin, and Supplement. 142. Grasshoppers in California. 147. Culture Work of the Substations. 149. California Sugar Industry. 150. The Value of Oak Leaves for Forage. 151. Arsenical Insecticides. 152. Fumigation Dosage. .53. Spraying with Distillates. ! 54. Sulfur Sprays for Red Spider. : 50. Fowl Cholera. ! 58. California Olive Oil : its Manufacture. 59. Contribution to the Study of Fermentation. 100. The Hop Aphis. 101. Tuberculosis in Fowls. (Reprint.) 102. Commercial Fertilizers. (Dec. 1, 1904.) 103. Pear Scab. 104. I 'on 1 try Feeding and Proprietary Foods. (Reprint.) 105. Asparagus and Asparagus Rust in California. 100. Spraying for Scale Insects. 107. Manufacture of Dry NVines in ITot Countries. 108. Observations on Some Vine Diseases in Sonoma County. 109. Tolerance of the Sugar Beet for Alkali. 170. Studies in Grasshopper Control. 171. Commercial Fertilizers. (June 30. 1905.) 172. Further Experience in Asparagus Rust Control. 174. A New Wine-Cooling Machine. 175. Tomato Diseases in California. 170. Sugar Beets in the San Joaquin Valley. 177. A New Method of Making Dry Red Wine. 178. Mosquito Control. 179. Commercial Fertilizers. (June, 1900.) 180. Resistant Vineyards. 181. The Selection of Seed-Wheat. 182. Analvsis of Paris Green and Lead Arsenate. Proposed Insecticide Law. 183. The California Tussock-moth. 184. Report of the Plant Pathologist to July 1, 1906. 185. Report of Progress in Cereal Investigations. 180. The Oidium of the Vine. 187. Commercial Fertilizers. (January, 1907.) 188. Lining of Ditches and Reservoirs to Prevent Seepage Losses. 189. Commercial Fertilizers. (June, 1907.) 190. The Brown Rot of the Lemon. 191. California Peach Blight. 192. Insects Injurious to the Vine in California. 193. The Best Wine Grapes for California ; Pruning Young Vines ; Pruning the Sultanina. 194. Commercial Fertilizers (Dec. 1907). 28 PUBLICATIONS. CIRCULARS. No. 1. Texas Fever. No. 26. 2. Blackleg. 3. Hog Cholera. 27. 4. Anthrax. 5. Contagious Abortion in Cows. 7. Remedies for Insects. 28. 9. Asparagus Rust. 10. Reading Course in Economic Entomology. (Revision.) 29. 11. Fumigation Practice. 12. Silk Culture. 13. The Culture of the Sugar Beet 15. Recent Problems in Agriculture. What a University Farm is 30. for. 31. 16. Notes on Seed-Wheat. 17. Why Agriculture Should be Taught in the Public Schools. 32. 18. Caterpillars on Oaks. 33. 19. Disinfection of Stables. 21. The Advancement of Agricul- 34. tural Education. 22. Defecation of Must for White Wine. 35. 23. Pure Yeast in Wineries. 24. Olive Pickling. 25. Suggestions Regarding Exam- 36. ination of Lands. Selection and Preparation of Vine Cuttings. Marly Subsoils and the Chlo- rosis ' or Yellowing of Citrus Trees. A Preliminary Progress Report of Cereal Investigations, 1905-07. Preliminary Announcement Con- cerning Instruction in Prac- tical Agriculture upon the 1 University Farm, Davisville, California. White Fly in California. The Agricultural College and Its Relationship to the Scheme of National Education. White Fly Eradication. Packing Prunes in Cans. Cane Sugar vs. Beet Sugar. California State Farmers' In- stitute at the University Farm. Southern California Patholog- ical Laboratory and Citrus Experiment Station. Analyses of Fertilizers for Con- sumers. Copies may be had on application to DIRECTOB OF EXPERIMENT STATION, Berkeley, Cal. UNIVERSITY OF CALIFORNIA PUBLICATIONS. COLLEGE OF AGRICULTURE, AGRICULTURAL EXPERIMENT STATION, BERKELEY, CALIFORNIA. GRAPE CULTURE IN CALIFORNIA. (ITS DIFFICULTIES; PHYLLOXERA AND RESISTANT VINES; OTHER VINE DISEASES.) BY FREDERIC T. BIOLETTI. IMPROVED METHODS OF WINE MAKING. BY FREDERIC T. BIOLETTI. YEASTS FROM CALIFORNIA GRAPES. BY HANS C. HOLM. Rupestris St. George. BULLETIN No. 197 (Berkeley, July, 1908.) SACRAMENTO: w. w. SHANNON, : : : : SUPERINTENDENT STATE PRINTING. 1908. BENJAMIN IDE WHEELER, Ph.D., LL.D., President of the University. EXPERIMENT STATION STAFF. E. J. WICKSON, M.A., Director and Horticulturist. E. W. HILGARD, Ph.D., LL.D., Chemist. W. A. SETCHELL, Ph.D., Botanist. ELWOOD MEAD, M.S., C.E., Irrigation Engineer. (Absent on leave.) LEROY ANDERSON, Ph.D., Dairy Industry and Superintendent University Farm. M. E. JAFFA, M.S., Nutrition Expert, in charge of the Poultry Station. C. W. WOODWORTH, M.S., Entomologist. R. H. LOUGHRIDGE, Ph.D., Soil Chemist and Physicist. G. W. SHAW, M.A., Ph.D., Agricultural Technologist, in charge of Cereal Stations. GEORGE E. COLBY, M.S., Chemist, in charge of Agricultural Chemical Laboratory. RALPH E. SMITH, B.S., Plant Pathologist and Superintendent of Southern California Pathological Laboratory and Experiment Station. Whittier. A. R. WARD, B.S.A., D.V.M., Veterinarian and Bacteriologist. E. W. MAJOR, B.Agr., Animal Industry. H. M. HALL, M.S., Assistant Botanist. H. J. QUAYLE, A.B., Assistant Entomologist. Whittier. W. T. CLARKE, B.S., Assistant Horticulturist and Superintendent of University Extension in Agriculture. JOHN S. BURD, B.S., Chemist, in charge of Fertilizer Control C. M. HARING, D.V.M., Assistant Veterinarian and Bacteriologist. H. A. HOPPER, B.S.A., Assistant in Dairy Husbandry. J. H. NORTON, M.S., Assistant Chemist in charge Fertilizer } Citrus Experiment T. FOTNTBS, A^tant Horticulturist, Stattm ' Rtmrsid '' E. B. BABCOCK, B.S., Assistant Plant Pathologist. E. H. SMITH, M.S., Assistant Plant Pathologist. F. L. YEAW, B.S., Assistant Plant Pathologist. H J RAMSEY, M.S., Assistant Plant Pathologist, ) Southern California Patholog- C. O. SMITH, M.S., " " ) ical Laboratory, Whittier. R. E. MANSELL, Assistant in Horticulture, in charge of Central Station Grounds. RALPH BENTON, B.S., B.L., Assistant in Entomology (Apiculture). A. J. GAUMNITZ, M.S., Assistant in Cereal Investigations. RACHAEL CORR, M.A., Assistant in Cereal Laboratory. HANS C. HOLM, B.S., Assistant in Zymology. P. L. McCREARY, B.S., Laboratory Assistant in Fertilizer Control. F. E. JOHNSON, B. L., Assistant in Soil Laboratory. M. E. STOVER, B.S., Assistant in Agricultural Chemical Laboratory. D. R. HOAGLAND, A.B., Assistant in Agricultural Chemical Laboratory. CHARLES FUCHS, Curator Entomological Museum. P. L. HIBBARD, B.S., Assistant Fertilizer Control Laboratory. M. E. SHERWIN, Field Assistant in Agronomy. W. H. VOLCK, Field Assistant in Entomology. Watsonville. E. L. MORRIS, B.S., Field Assistant in Entomology. San Jose. J. S. HUNTER, Field Assistant in Entomology. San Mateo. D. L. BUNNELL, Clerk to the Director. JOHN TUOHY, Patron. ) Tulare Substation, Tulare. J. T. BEARSS, Foreman, \ J. W. ROPER, Patron, ) University Forestry Station, Chico. E. C. MILLER, In charge, \ University Forestry Station, Santa Monica. N. D. INGHAM, Foreman, \ VINCENT J. HUNTLEY, Foreman of California Poultry Experiment Station, Petahima. The Station publications (REPORTS AND BULLETINS), so long as avail- able, will be sent to any citizen of the State on application. GRAPE CULTURE IN CALIFORNIA BY F. T. BIOLETTI. WORK OF THE STATION. The growing of grapes and the industries based thereon are in a peculiar sense Californian. California produces, approximately, all the raisins, three quarters of the wine, and a large share of the ship- ping grapes of the United States. All these industries have increased in importance with a steady and healthy growth during the last thirty or forty years, and during the last ten years the increase has been about 75%. The new plantations have been particularly numerous and extensive during the last five years. At present there are over 200,000 acres of vineyard in the State, and the prospects of continued expansion are favorable. The growing of grapes has many practical and sentimental attrac- tions both for capitalists and small farmers. No other branch of agriculture offers more certainty of steady, profitable returns for invested capital, and none offers superior inducements to the owner of a few acres of land in his effort to make a pleasant and adequate living by his own labor. There is very little of the arable land of California which is not capable of producing abundant crops of good grapes, and the future output will be limited only by the demand and extent of the market. The very attractiveness of viticulture and the peculiar suitability of California for its development involve dangers which must be avoided if we are to reap the best results from our advantages. A very large proportion of our new arrivals and settlers engage in some branch of grape-growing. Most of them have no knowledge of the business, or have preconceived ideas which are incompatible with our conditions. These conditions are so different from those of the Eastern States, and even from those of most of the grape-grow- ing regions of Europe, that grape-growers from New York, Bordeaux, Burgundy or the Rhingau often fail to obtain better results than those who have had no previous practical experience in cultivating the vine. 116 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. In spite of California's superb advantages as a grape-growing region, statistics show that our average crop per acre is considerably less than that of Algeria or many parts of the south of France, and is hardly superior to that of Burgundy or the Rhingau. On the other hand, the crops on our best vineyards, vineyards which are handled properly, with due regard to our special conditions, are unexcelled anywhere in the world. Two things, therefore, are urgently needed. First, the diffusion of special viticultural and enological knowledge, and second, the scien- tific and practical investigation of our peculiar problems. Since 1876 the Agricultural College at Berkeley has given more or less attention to the work of instruction and research in viticulture. At first Prof. E. W. Hilgard conducted this work almost single-handed, and, as in so many other departments of agriculture, laid the solid foundations which have contributed so much to the improvement of our cultural methods. From 1880 to 1894 the Viticultural Commission did much to instruct our grape-growers and wine-makers in the theory and practice of their arts. Since 1894 the only institution in California in fact, in the United States which has given special attention to viticulture has been the Agricultural College and Experiment Station of the University of California. The work has been carried on somewhat spasmodically, owing to the lack of regular appropriations. At some sessions of the Legislature provision has been made for this purpose; at others it has been omitted. This uncertainty of support makes much of the work which ought to be done impossible, and all of it more difficult. Experiments are commenced, observers are trained, but, before the most valuable results are obtained, the work has to cease for lack of funds. When a new appropriation is made, new observers have to be trained and much of the experiment work has to be recommenced. This results in loss of time and efficiency and a much smaller output of valuable infor- mation than would be possible if there could be more continuity in the work. The Legislature of 1905 set aside $10,000 for the furtherance of viticultural research during the two years commencing July 1, 1905, and a considerable amount of progress has been made. Besides the work of investigation carried out under the provisions of the bill passed by the last Legislature, the regular viticultural work of the University has been carried on. This work is, in the main part, educational. It consists of courses in grape-growing and wine-making to regular students, and short courses in the same subjects to special BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 117 students. Short courses and viticultural institutes have also been given, so far as our time and resources have allowed, for the benefit of those actually employed in the industry. The short courses at Berkeley to grape-growers and wine-makers actively engaged in the occupations have not been a success, owing to the small number who have been able to leave their work long enough to attend them. The special viticultural institutes, on the other hand, have met with a success that is very encouraging. These institutes are given, so far as possible, in any viticultural center wherever a sufficient demand is manifested and the traveling expenses of speakers is borne by the Farmers' Institute appropriation. They last either one or two days, usually Saturday, or Friday and Saturday. They are not only confined strictly to viticulture, but attempt to treat only one particular part of this subject. The part chosen is, so far as practicable, one of actual interest at the season when the institute takes place. The plan adopted is to accompany the lectures by practical demon- stration in the vineyard. Two or three hours in the morning are usually all that are devoted to lectures. The afternoon is spent in the vineyards, where the ideas developed in the lectures are put into practice. An evening session is sometimes held to discuss the work of the day or to treat some subject unsuited to field demonstration. An attempt is always made to adapt the instruction to the imme- diate needs of the locality and season, and to the time available. The principal topics which so far have been taken up at these viticultural institutes are the following: 1. Starting a new vineyard. 2. Pruning table grapes. 3. Pruning wine grapes. 4. Pruning raisin grapes. 5. Pruning young vines. 6. Oidium of the vine and methods of control. 7. The phylloxera of the vine. 8. Resistant vines. 9. Methods of grafting. 10. New varieties of grapes. 11. Fertilization of vineyards. Another important phase cf the viticultural activities of the University consists in an ever-increasing correspondence with grape- growers and wine-makers. Advice is given, suggestions made, and, where practicable, vineyards and cellars are visited on request. 118 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Perhaps the most effective part of our work at present consists of spreading the knowledge, gained in the older districts by veteran growers, among new arrivals and in new districts. The repetition of costly mistakes is thus often prevented. More of this work should be done, but the small number of observers and experts prevents very great expansion at present. Instead of two or three trained viticultur- ists, the extent of California and the magnitude of its industries require a dozen. It is to be desired that an efficient expert, trained in the science and practice of grape-growing and wine-making, should be stationed in every large viticultural section, ready to advise all who apply. The expense would be compensated a hundredfold by prevent- ing the frequent repetition of many costly mistakes. Easily avoidable loss of hundreds of thousands of dollars occur every year through ignorance of the best methods of pruning, grafting, sulfuring, ferment- ing, packing, and all the various operations of the vineyard and cellar. Men suitable for such work in California are difficult to find. It requires an amount of practical experience and technical training which few possess. These requirements must, moreover, be coupled with personal qualifications of industry and judgment that make their possessors too valuable in other pursuits to make it possible to retain them unless they can be assured continuous employment at good salaries. Publications of the Viticultural Department. In the period of three years from January 1, 1905, to December 31, 1907, ten bulletins and five circulars have been published by the Viticultural Department. These represent the principal portion of the work which has been so far completed as to be of immediate use to growers and wine-makers. Minor topics and incomplete investigations are discussed shortly in the present bulletin. PHYLLOXERA. This vine disease is well established now in nearly every large grape- growing section, except those of southern California. There are still large areas of vineyard, however, in the San Joaquin and Sacramento valleys which have thus far escaped the pest. The slowness with which it has spread in these regions is remarkable when we compare it with the rapidity with which vineyards were attacked and destroyed in Europe, and also in Sonoma, Napa, Santa Clara and other of the coast counties. There are several obvious reasons which account in part for this slow extension. The various grape-growing districts are scattered throughout a wide plain, more or less isolated from each other by miles of grain or pasture lands. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 119 Many of the vineyards are planted in sandy soil, where the progress of the pest is always slow. The natural power of resistance to this disease possessed by the Flame Tokay, though not sufficient alone to save it permanently, is no doubt a factor in saving vineyards of this variety from rapid destruction. There seems some reason to believe that this variety under special conditions, when growing in deep, rich soil, especially if somewhat sandy, might be kept sufficiently vigor- ous by careful cultivation and fertilization indefinitely. It would be unsafe to trust to this for immunity, however, unless the vineyard were situated where it could, if necessary, be given a winter sub- mersion of three or four weeks every few years. It is a mistake to suppose, however, that rich soil or ordinary irriga- tion give any practical degree of immunity. Vineyards in the richest and most copiously irrigated regions of the San Joaquin Valley have already been destroyed by the pest. What the effect of alkaline soil has in this respect is as yet undetermined. When we have made every allowance for the known factors which operate to delay the spread of the Phylloxera in the great central valleys of California, they do not seem sufficient to completely account for its slowness. Even the fact that the vineyards and wine-growing regions are widely separated by fields where no vines grow is insiiffi- cient to account for the slow spread of the insect, when we know that the winged form may be transported by the wind 20 or 30 miles and still infect the vine on which it is deposited. The most plausible theory seems to be that the winged form is absent or extremely rare in the interior of California. In fact, the winged form is produced most abundantly on American species of vines, growing in cool, moist situations, and especially when rains occur in June and July. As such conditions never occur in the interior valleys, it is not strange that the winged form should be rare. No record exists of winged individuals having been seen in California except in the coast valleys. If this theory is correct, the only means the insect has of spreading from one vineyard to another in the- great valleys is by crawling from vine to vine or by being carried on cuttings or roots. This makes the delay of the extension of the pest by proper quarantine measures par- ticularly useful and effective. These measures are of two kinds those which can be carried out by each grape-grower himself, and those which require the enforcement of ordinances by quarantine officers. The first are as important and more generally practicable than the last. If no winged insects occur there is no danger of introducing the 120 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. pest on cuttings, for these never carry the root form. As their absence, however, is not proved anywhere, and as cuttings may come from regions where they do exist, it is the part of wisdom to disinfect all cuttings before planting. Disinfection of Cuttings. The easiest and most effective method for the use of the grape-grower is by means of bisulfid of carbon. The method of using the bisulfid is as follows: Place the cuttings in a barrel or vat or a box made tight by means of a thick coat of paint or of paper pasted on the inside. On top of the cuttings place a saucer or other shallow dish, into which to pour the bisulfid of carbon. An ordinary saucer will hold enough for a box of 27 cubic feet or a 200-gallon vat. For larger receptacles it is better to use two or more saucers. Deeper vessels will not do, as the evaporation is not sufficiently rapid. After pouring the bisulfid into the saucer, cover the box with an oiled canvas sheet or other tight-fitting cover, and allow to stand for from forty-five to ninety minutes. At the end of this time there should be a little of the bisulfid left. If it has all evaporated this is proof that insufficient was used. No flame lights should be used, as the liquid burns easily and the fumes form an explosive mixture with the air. Lately, in Switzerland, a cellar was wrecked and a man killed by an explosion of vapors of bisulfid owing to a neglect of this precaution. Care should be taken not to spill any of the liquid on the cuttings, as it may kill them. It is advisable to cut off about half an inch of the lower end of the treated cuttings before planting, as the vapor injures the open pith. Besides disinfecting the cuttings in this way, all the packing material in which they come should be burnt, or, if valuable, dipped in boiling water. Practically, it is impossible to disinfect rooted cuttings by this means satisfactorily on account of the difficulty of killing all the Phylloxera without seriously injuring the vine roots. Disinfection of Roots. For the disinfection of rooted vines dipping in hot water is recommended by the best European authorities. The roots should remain in water at 125F. to 130F. for ten minutes. The same treatment may be used. for cuttings. The method has several inconveniences, however. Only small quantities can be disinfected at one time, and it requires great care to see that, on the one hand, the heating is sufficient to kill the insects, and, on the other, not sufficient to injure the vines. Experiments with this method by the University are not promising, and many of the rooted vines were killed. It is probable that disinfection by means of hydrocyanic gas as practiced for nursery stock would be effective, but data is lacking on this point. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 121 Delaying the Spread of Phylloxera. When the Phylloxera has entered the vineyard it can not be found until it has increased suffi- ciently to kill or seriously weaken a vine. By this time it has usually spread to at least several neighboring vines. It is usually hopeless to attempt to eradicate it in this case without digging up and destroying a very large number of vines, and even in this case there is no assurance that other infected spots do not exist. Something, and in some cases, much, however, can be done to delay its spread, and the main part of a vineyard may often be preserved for many years by proper measures. The first thing to be done when infection is first discovered is to dig up all the dead and weakened vines and a block surrounding them, including at least three rows of apparently healthy vines on all sides. These vines should be all burned on the spot or piled up in the center of the infested block, sprayed with coal oil, and left for several months until the dry summer air has certainly killed all the insects on their roots. A more effective method is to treat the infested area with enough bisulfid of carbon to kill both the vines and the Phylloxera. This is done by making holes with a crowbar 12 inches deep every 18 inches over the whole area. Into each hole is poured 1% ounces of bisulfid and the hole closed immediately with the foot. This treat- ment is best applied in April or May, after the vines have started and before the ground becomes too dry. If any vines survive this treatment, a new dose of 1 ounce to the 18 inches should be applied three weeks later. However carefully either of these methods is carried out it affords only temporary relief. In Switzerland, Algeria, and Germany, where such methods have been applied with the utmost strictness and under military supervision, the spread of the pest has been checked but not stopped. In any case, plows or cultivators should not pass through affected spots in the healthy parts of the vineyard. Cultivation is one of the most effective means of carrying the root insects from one part of the vineyard to another. Every effort should be made to discourage the introduction of cuttings, and especially of roots, from infested to uninfested districts. Wherever possible it is best to obtain planting stock in the immediate neighborhood. Reestablishment of the Vineyard. When a vineyard becomes thor- oughly infested, that is, when it contains several scattered, diseased spots, or when 10% to 15% of the vines are known to be attacked, it is useless to attempt to delay the pest by these means. The only 122 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION. course to be followed in this case is to cultivate each block as long as it produces paying crops, and then to dig it up and replant it with bench grafted resistants. It is very bad policy to commence replanting single vines or small areas each year as they fail. A young resistant planted among old viniferas never gets the proper care, and has no chance to do its best. Where this method is adopted, the vineyard finally becomes a mixed lot of vines of various ages and of various degrees of unprofitableness. Replanting should be done in regular, rectangular blocks. Planting New Vineyards. In planting a vineyard in new soil, whether we should plant grafted resistants or viniferas on their own roots is to be determined by local conditions. If there is great likelihood of our vines being attacked before they have borne two or three crops it would be folly to plant anything but resistants. Hundreds of acres, in the aggregate, which have been planted in Phylloxera-infested districts have died before they ever produced a crop. On the other hand, if there is a fair chance of the vineyard remaining uninfested for many years it is often safe to plant non-resistants, and thus save the $30.00 to $40.00 per acre extra which a resistant vineyard will cost. In the counties of Marin, Sonoma, Napa, Solano, Contra Costa, Alameda, Santa Clara, Santa Cruz, and San Mateo, where the Phylloxera is very generally distributed, it is throwing work away to plant any- thing but resistant vines. The same is true of those districts in the Sacramento and San Joaquin valleys where the pest has obtained a secure foothold. In any district it is unsafe to plant non-resistants anywhere within two or three miles of an infested vineyard. RESISTANT VINES. The demand for information regarding Phylloxera-resistant vines becomes every day more pressing. The problems of the adaptation of various stocks to various soils and climates, of the suitability of various combinations of stock and scion, and of the best methods of grafting have, therefore, been given as much attention as possible. Rupestris St. George. Probably nine tenths of the resistant vines being planted in California at the present time are Rupestris St. George. This is undoubtedly a most excellent stock for a large portion of the country. It is giving its best results in the interior valleys and in the warmer parts of the coast valleys and hillsides. Numerous cases of partial failure, however, have been noted, which make it certain that for manv locations a better stock is to be found. HLTLLETIN 197. GRAPE CULTURE IN CALIFORNIA. 123 Most of the cases of failure have been reported from Sonoma, Napa, and Santa Clara counties. They can nearly all be traced to unsuitable soil conditions. "Where there is an impermeable subsoil (bed rock or compact clay) the St. George usually fails. Under such conditions, if the soil is dry, the vines make poor growth; if wet, the roots decay and the vines die. A very compact clay soil, even when deep, seems unsuited to this variety, at least when grafted with certain varieties, such as Emperor and Cornichon. In some cases the vines grow well, but the crops are unsatisfactory. This has been noted only in rich valley soil of the coast counties and only with certain varieties. A similar condition has often been noted in Europe, but it is usually easily overcome by longer pruning and diminishes with age. A more serious defect has been found in some of the cooler districts. Many varieties when grafted on St. George ripen from one to two weeks later than when grafted on Kip aria and some other stocks. This is due, probably, to the great vigor of the stock, which keeps the vine growing late. It is a serious defect wherever there is difficulty in obtaining the desired amount of sugar in the grapes and wherever late grapes are liable to injury from the autumn rains. It seems inadvisable, therefore, to plant St. George in cool situations, on northerly slopes of the coast ranges, in localities close to the coast, or on shallow, wet, very rich or stiff clay soils in any locality, and to use it only on deep, permeable soils in the warmer districts and locations. EXPERIMENTS WITH VARIOUS STOCKS. Through the courtesy of Mr. J. K. Moffit we have been able to take some very interesting notes on resistant vines at an experiment plot in his vineyard at St. Helena, Napa County. This plot was planted in 1900, under the direction of the Experiment Station, with the resistant stocks and bench grafts which served for the experiments detailed in Bulletin 127. Since that time it has been looked after by Mr. B. Bruck, the manager of the vineyard. The fol- lowing is a summary of the notes taken in 1905. Three rows of 25 vines each were planted with various varieties of bench grafts; in one row the stock being Rupestris St. George, in another Riparia Gloire, and in the third Riparia Grande Glabre. In most cases there were two vines of each variety on the same stock, in some cases three, and in some only one. The results are, therefore, not quite so convincing as if they had been made on a larger scale: 124 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION. Bench Grafted Vines. Planted in 1900. Notes taken in 1905. SCION. Stock. Growth in May. Crop. Remarks. Klein berger _ Rip. gloire Heavy Poor Much broken bv wind. Klein berger St. George Heavy None Nearly all canes blown off. Sultana Rip. gloire Strong Good Berries very large. Sultana St. George Strong Fair Berries smaller than on Rip Blue Portuguese- Burger Rip. gloire Rip. gloire. Fair Good. Very large 23 pounds to one vine. Pinot Chardon'y Rip. gloire _ _ Fair __ Good. Pinot Chardon'y Semillon St. George Rip. gloire Very strong- Strong Fair. Large. Palomino St. George Very strong Large. Valdepenas Rip. gloire Very strong Very large 22 pounds to one vine. Valdepenas St. George Very strong Poor. Gros Mansenc Rip. gloire Fair Heavy. Gros Mansenc Rip. gr. glabre Strong Fair. Folle blanche .._ Fresa Rip. gloire Rip. gloire Strong Fair Very large Fair. 25.5 pounds to one vine. Fresa Rip. gr. glabre Strong Fair. Marsanne Rip. gloire Strong Fair. Marsanne _ _ Rip. gr. glabre Strong Large. Marsanne St. George Fair __ . Fair. Vernaccia Rip. gloire Strong Large. Vernaccia Rip. gr. glabre Very strong Fair. Vernaccia St. George Strong Fair. Cornichon Rip. gr. glabre Fair Fair. Cornichon St. George Very strong- Good. Aramon Rip. gr. glabre Strong . Good _ 22.5 pounds to one vine. Mataro Rip. gr. glabre Weak Good. Mourisco preto ._ Huasco Rip. gr. glabre Rip. gr. glabre Very strong- Fair Fair. Fair Much coulure. Sultanina Rip. gr. glabre Very strong Poor. Verdot Rip. gr. glabre Very strong Good. Barbera St. George Very strong Large. Beba St George Very strong Good Berries very small. Mantuo St. George Very strong Fair Berries very small. Franken Riesl... Alicante Bous. __ Perm no St. George St. George St. George Very strong- Very strong- Very strong Small Very large. Large. Much coulure. In a general way, all the varieties on all stocks looked sufficiently vigorous, with the exception of the Mataro on Riparia Grande Glabre. The vines on St. George were nearly always more vigorous than those on Riparia. Of the two Riparias the Grande Glabre seemed a little the more vigorous. The relative standing of the three stocks with regard to vigor is indicated in the following summary: Comparison of Vigor of Vine on Various Stocks. VIGOR. Number of Varieties on Riparia Gloire. Riparia GrandeGlabre. St. George. Verv strong 2 5 4 5 X 2 1 11 2 1 Strong Fair Weak BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 125 The only variety which looked .very weak was the Mataro on Rip. Grande Glabre. This corresponds with European experience where it is recommended to graft this variety only on vinif era X American hybrids, such as Aramon X Rupestris No. 1 and Mourvedre X Rupestris 1202. Where the growth is marked "fair" the slight lack of vigor could generally be ascribed in part to the heavy crop. Exceptions to this are the Cornichon and Huasco (Muscat of Alexandria), which not only lacked vigor but also crop on Riparia. The bearing on the various stocks may be compared in the same way in the following summary: Comparison of Crops on Various Stocks. CROP. Number of Varieties on Riparia Gloire. Riparia Grande Glabre. St. George. Very large 4 2 3 2 1 1 3 6 1 1 3 2 5 3 Large Good Fair Small This is hardly a fair comparison, for the reason that in most cases the same variety was not grafted on all three stocks. In all cases, however, where the same variety was grafted on both Riparia and Rupestris St. George, with the exception of the Cornichon and Fresa, the vines on Riparia had larger crops. This is shown by the following comparison : Comparison of Crops on Riparia and Rupestris. VARIETY. Riparia. Rupestris St. George. Kleinberger Poor None. Sultana Good Fair. Chardonay Good ._ -. .- Fair. Valdepefias Very large -_ Poor. Gros Mansenc Heavy Fair. Fresa Fair - Fair. Marsanne Fair to large Fair. Vernaccia Fair to large Fair. Cornichon Fair Good. Crop of Vines^n It should be noted that all varieties indiscriminately were pruned short. If those which need long pruning when ungrafted had been pruned long, the showing would undoubtedly have been more favorable to the St. George. It is a very valuable characteristic of the Riparia, however, that it enables us to obtain good crops with short pruning 126 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. from varieties which on their own roots require long pruning. This is exemplified in table on page 124 by the fact that of eleven varieties which ordinarily require long pruning eight varieties bore good . crops with short pruning when grafted on Riparia ; of seven long-pruning varieties grafted on St. George, only one bore good crops when pruned short. This was especially noticeable with the Valdepefias and Gros Mansenc, which bore very fine crops on Riparia Gloire and very little on St. George. The only long-pruning variety which bore well on St. George was the Barbera. Of the short pruning varieties the following bore well on St. George: Palomino, Alicante Bouschet, Perruno, and Cornichon. The quality of the grapes was in nearly all cases, where a comparison was possible, better on Riparia stock than on St. George. The grapes were larger and sweeter. The higher sugar content was, moreover, usually accompanied by higher acidity, showing that the grapes were better developed. The following table includes varieties which were bearing on both Riparia and St. George, and shows very clearly the superiority of the former stock in regard to the quality of the must : Analysis of Grapes from Grafted Vines. St. Helena Plot. October 6, 1905. SCION. Stock. Sugar. Acid. Remarks. Valdepefias Rip. gloire 27.5 .65 Very ripe, a few grapes shriveled. Valdepefias St. George 23.5 .56 Crop very small. Zinfandel Rip. gloire 26.5 .92 Zinfandel St. George 24.0 .85 Many dried grapes. Aramon Mourisco preto Rip. gr. glabre-_ Rip. gr. glabre 18.2 23.0 .96 .66 Grapes small for Aramon. Blue PortugUf se Rip. gloire 32.2 .53 Much overripe. Mataro Rip. gr. glabre__ 19.0 .75 Gros Mansenc Rip. gr. glabre 26. 7 1.12 Gros Mansenc Rip. gloire 24.1 1.20 Fresa Rip. gr. glabre . 24.0 .83 Fresa Rip. gloire 26.6 .92 Alicante Bouschet St. George 18.2 .86 Barbera St. George 26.1 .87 Marsanne Rip. gr. glabre 25.0 .67 Marsanne Rip. gloire 23.3 .50 Marsanne St. George 21.6 .62 Chard on ay Rip. gloire 25.0 .60 Chardonay __ Seniillon Rip. gr. glabre __ Rip gloire 22.8 26.5 .87 .68 Huasco Rip. gr. glabre __ 27.1 .64 Palomino St. George 26.5 .55 Palomino St. George 29.0 .45 Kleinberger Rip. gloire 22.6 1.12 Perruno St. George 23.4 .47- Franken Riesling St. George 26.5 .59 Sultana St George 24.7 .75 Sultana Rip. gloire 24.0 .75 Mantuo St George 27.1 .39 Many small grapes. Beba Cornichon Rip. gr. glabre __ Rip. gr. glabre __ 20.3 20.3 .41 .77 Grapes very small. Cornichon St. George 18.4 .65 Grapes very fine. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 127 Comparison of Composition of Grapes on Riparia and St. George. VARIETY. STOCK. Riparia Gloire. Riparia Grande Glabre. St. George. Valdepenas Sugar. 27.5 26.5 24.1 25.6 27.5 23.3 25.0 24.0 Acid. .65 .92 1.20 .92 .84 .50 .60 .75 Sugar. Acid. Sugar. 23.5 24.0 Acid. .56 .85 Zinfandel Gros Mansenc 26.7 24.0 27.6 25.0 22.8 1.12 .83 .92 .67 .87 Fresa Vernaccia 24.2 2L 6 .61 .62 Marsanne Chardonav Sultana 24.7 18.4 .75 .65 Cornichon 20.3 .77 Mean 25.4 .80 24.4 .86 22.7 .67 These observations warn us that we should not hastily reject the Riparia as a stock. While there have been many failures on Riparia, these failures can be traced to lack of selection of the proper kind of Riparia and to the planting of Riparia on unsuitable soil. If we plant Riparia Gloire on rich, deep, loose, moist but well-drained soil, especially in the cooler districts, and avoid overbearing by too long pruning, we will probably obtain better results than by planting Rupestris St. George under the same conditions. Zinfandel. A very interesting part of the plot is a series of rows of different stocks field-grafted in 1900 with Zinfandel. Each row con- sisted of about 20 vines. A summary of the notes taken is given in the following table : Notes on Zinfandel Grafted on Various Stocks. Vines 5 years from grafting. 1905. St. Helena. STOCK. GROWTH. Crop. Remarks. May. Aug. Sept. Rupestris Martin Vigorous. Vigorous- Vigorous- Good Good Large. Good Looked a little weak in August, but recovered. Sugar 24.0, acid .85, many dried grapes. More vigorous than 3309, less than St. George. Vines all weakly. Sugar 26.5, acid .92. Growth uneven. 10114 Fair ._ Good Strong Rupestris* St. George _. 3309 Good.. Fair Strong Strong Fair .. Fair _ Heavy Heavy Fair .. Good-. Large . Good. Good. Fair. 101 14 Vigorous- Uneven __ Strong Fair .. Weak. Viala Riparia Gloire Solonis Weak g : Fair . I Strong Fair II Fair II Fair .. Fair .. Good Rupestris Mission Munson Riparia Grande G la bre. Fair II It is encouraging to find that our principal wine grape has given good results on all the principal stocks. The vigor and bearing of the vines on Riparia X Rupestris 3309 and 101 14 were particularly fine. 128 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Mondeuse. One of the rows of this variety is grafted on Riparia Grande Glabre and is very vigorous and bearing good crops. About 600 vines of the same variety are grafted on St. George and are even more vigorous, but the crop is uneven. Owing to the vigor of the growth many canes were broken by the wind in the spring, which probably accounts for the variations in bearing. All the vines show a considerable amount of coulure. Semillon grafted on St. George made good growth, but the crop was unsatisfactory and much coulured. Ferrara on St. George (about 75 vines) showed excellent growth, but only a medium crop and much coulure. Tokay on St. George (50 vines) was excellent. The vines were ex- tremely vigorous and the crop good. The bunches were not compact, but were well filled. The tendency of the stock to produce coulure in this case had resulted simply in a thinning of the berries, which was an advantage. St. Macaire on St. George has done very well, being vigorous, and producing good crops with short pruning. Bench Grafts and Field Grafts. In starting this experiment plot some of the rows were planted with bench grafts and the others with rooted resistants, which were field-grafted the following year. This gives us a good comparison of the two methods as regards the securing of a good stand. Comparison of Bench Grafting and Field Grafting. Qti, a No. Growing No. Failed by 5th Year. 5th Year. FIELD GRAFTING (Zinfandel) Rupestris St. George. _. .. 39 = 68% 18 = 32% Riparia X Rupestris 3309 __ _*36 = 72% 13 = 28% Riparia X Rupestris 101 14 ._ _ 42 = 84% 8 = 16% Rupestris Martin _ 26 = 55% 21 = 45% Vialla_._ ... 16 = 70% 7 = 30% Total.. ..,__. -159 = 70% 67 = 30% BENCH GA,O- Mondeuse on St. George. _. __600 = 98% 14 = 3% Tokay on St. George ____ - 48 = 96% 2=4% Ferrara on St. George ____ ._ 70 = 93% 5=7% Total 718 = 97% 21= 3% As all these vines were growing close together on the same kind of soil, and under the same management, the comparison speaks eloquently in favor of bench grafts as a means of obtaining a perfect "stand." HULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 129 EXPERIENCE OF GROWERS. WINE GRAPES. An attempt has been made to collect the experience with various resistant vines of growers in various sections. The experience of the older vineyards is of little use, and, in fact, apt to be misleading, as they were nearly all grafted on unselected Riparia and Rupestris. The stocks in the newer resistant' vineyards are nearly all Rupestris St. George and Lenoir, so that the data for comparison are meagre. Some of the reports received, however, are interesting and are given here. NAPA COUNTY. B. Bruck, St. Helena. Vigor. Crop. Zinfandel on St. George, 7 years old, red, clay, hill soil ...Good Fair Zinfandel on Lenoir, 8 years old, red, clay, hill soil Good Fair Burger on St. George, 9 years old, rich, dry soil Good Large Palomino on Lenoir, 9 years old, rich loam i Good Good Carignane on Lenoir, 8 years old, rich loam Fine Fine Sauvignon vert on Riparia, 14 years old, rich loam__ __Fine Fine Sauvignon vert on St. George, 5 years old, rich loam Fine Fair Johannisberger on Riparia, 10-14 years old, loamy soil Fine Fair Johannisberger on St. George, 6 years old Strong Poor Tokay on St. George, 7 years old, heavy soil Good Fair Tokay on Lenoir, 8 years old, gravelly soil ..Fair Fair Muscat on Lenoir, 8 years old, dry, gravelly Weak Good The vineyard to which these notes refer is the same as that in which the experiment plot, reported on above, is situated. The results cor- roborate these of the plot. The crops of varieties grafted on St. George vary from poor to fair, with the exception of the Burger, whose natural tendency to heavy bearing has here been retained when grafted on St. George. J. H. Wheeler, St. Helena. Zinfandel on St. George, 1-8 years old .-Vigorous and satisfactory. Zinfandel on Lenoir, 1-18 years old Vigorous and satisfactory. Zinfandel on Riparia -.Poor, gradually dying. Burger on Lenoir, 1-12 years old --Very vigorous, good crops. Muscat on Lenoir, 10 years old --Fair. Mr. Wheeler states that all varieties grafted on Lenoir yield about one half the crop which they formerly did when growing on their own roots, but that the crops are regular. The same varieties grafted on St. George yield from one half to two thirds the crops formerly obtained before the advent of Phylloxera. This report is sufficient to condemn both stocks for this vineyard, as the experience in Europe is that whenever a stock suitable to the variety of scion and the nature of climate and soil is used, the crop of grafted vines is always larger than that of vines on their own roots. There can be little doubt that the Riparia X Rupestris hybrids would give better results in this vineyard. 2 BUL. 197 130 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION. Mr. Wheeler states further that Lenoir gives late ripening and low sugar with all varieties, that the same varieties on St. George ripen about two weeks earlier and attain from 1% to 3% more sugar. These varieties on Riparia ripen still earlier (1 to 2 weeks) and attain 1% to 2% more sugar than on St. George. This corroborates the experience on the St. Helena plot. Or abb's Black Burgundy (Refosco) and Petite Sirah are said to fail occasionally on St. George, but a second graft on the same stock usually takes. This simply indicates a slight difficulty in grafting, and not necessarily any lack of affinity. Fred S. Ewer, Rutherford. Mr. Ewer finds the Lenoir a very satisfactory stock, as is shown by the following extract from a letter which he kindly wrote: I would like to say, on the start, that my knowledge of the different resistant stocks (except Lenoir) is so limited that I shall not attempt to say much about any other than the Lenoir. I have tried only three different resistants in all, Riparia, Rupestris St. George, and Lenoir, and all grafting on same was field work, as I have never been a believer in bench work for our place, believing we could get a vineyard quicker with the field grafting, and the little bench grafting I have done has proved it to my entire satisfaction. The Riparia was a total failure with us at Rutherford, and a partial success at our small vineyard at St. Helena. We planted 3,000 Rupestris in vineyard, and grafted them at one year old, and only got a stand of 30%, where with the Lenoir we nearly always got from 90% to 95% of a stand, so you can easily see why I favor the Lenoir. Under certain conditions, such as soil, climate, moisture, etc., I am inclined to think, from the experience of others, that the Rupestris is better than the Lenoir. but not for our place. My preference for the Lenoir, summed up briefly, is as follows, viz. : Vigorous growers, ease of taking the graft, fine union, and few, if any, suckers, if properly prepared before planting. I will say that as regards the bearing of the different varieties on resistant stock. I believe we get a better crop and more sugar now than we used to on the vinifera ; that is to say, on all varieties we have, such as Chas. Font, Golden Chasselas. Semillon, Sauvignon vert. Traminer, Burger of the white varieties, and Crabb's Black Burgundy, Alicante Bouschet, Petite Sirah, Beclan, and a few Zinfandel of the reds. I have Petite Sirah grafted on Lenoir fourteen years old, and growing strong and vigorous, and bearing good crops every year. I wish you could see the crop of grapes on them now ; it looks like eight tons to the acre. I believe I am the only person in this county who has grafted any Muscat on Lenoir, and my foreman said the other day there were more grapes on the vines than leaves, showing that the Muscat will do well on Lenoir ; they are now eight years old and doing well. It should be noted that the soil of Mr. Ewer's vineyard is very deep, rich, and liable to become very wet in the winter. These con- ditions are very favorable to the growth of new roots, and, to some extent, unfavorable to the Phylloxera. This is shown by the fact that some Zinfandel vines, on their own roots, are still bearing good BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 131 crops, though they have been infested with Phylloxera for ten years or more. Under such conditions, the low resistance of the Lenoir is sufficient. It would be unsafe to conclude from this that Lenoir would be sufficiently resistant in other soils and under other conditions. The failure of Riparia, noted both by Mr. Ewer and by Mr. Wheeler, is in part due no doubt to the use of unselected stock. If Riparia Gloire had been used it is probable that very different results would have been obtained. G. de Latour, Rutherford. Vigor. Crop. Zinfandel on St. George, 5 years old, gravelly soil Not good 3 tons Burger on St. George, 5 years old, gravelly soil__ Very good 6 tons Alicante Bouschet on St. George, 5 years old, gravelly soil-Good 4 tons Palomino on St. George, 5 years old, gravelly soil Very good 2 tons Sauvignon vert on St. George, 5 years old, gravelly soil Very good 2 tons Green Hungarian on St. George, 5 years old, gravelly soil- Very good 5 tons Petite Sirah oh St. George, gravelly soil Weak Good Grand Noir on St. George, 3 years old, gravelly soil Good 1^ tons Mr. de Latour states further "* * * it seems that Zinfandel does not succeed very well on St. George; the union with Petite Sirah seems defective also. The Riparia X Rupestris 3309 seems to be still better than the Rupestris St. George." SONOMA COUNTY. L. Justi, Glen Ellen. Reports that all the varieties of wine grapes in his district have grown vigorously and borne good crops on Lenoir, with the exception of the Petite Sirah, which sometimes fails. Alicante Bouschet and Burger do particularly well. K. Nagasawa, Santa Rosa. Zinfandel on St. George, 5 years old, on light ashy soil, becoming very hard in summer, are very vigorous and yield very well. Alicante Bouschet, Beclan and Muscadelle du Bordelais on the same stock are doing well, though too young to bear yet. SAN JOAQUIN COUNTY. F. and F. A. Arnold, Stockton. Nature of soil: 24 acres 3 parts adobe and 1 part river sand and slackens ; 3 to 6 feet deep ; no overflow for years ; no irrigation. Plowed 12 inches deep before planting cuttings; field grafting. Burger and Mission doing well on Rupestris St. George, Riparia Gloire, Riparia Grande Glabre, and Riparia X Rupestris hybrids. 132 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. SANTA CLARA COUNTY. Paul Masson, San Jose. Zinfandel on Rupestris St. George, 6 years old, satisfactory, good unions, healthy looking, but do not bear abundantly. Burger on Rupestris St. George, 4 to 7 years old, field grafted; bad. Poor success from beginning, many dying every year, apparently from poor unions and lack of affinity. Same results on sandy, deep, rich gravelly and rich loamy soils. Carignane and Pinot, 11 years old, planted on special soil, are doing well. "I have quite a few acres of 11-year-old vines grafted on Rupestris St. George, including the following varieties: Carignane Mondeuse, Alicante. Bouschet, Aramon, Grand Noir, Durif, Grenache, Pinot, Semillon, Sauvignon vert, Folle blanche, Colombar, Pinot blanc. These are all doing very well, and, if anything, more vigorous and prolific than ungrafted vines of the same age. Carignane and Grenache, 12 years old on St. George, have never failed to give a large crop, and Aramon also seems very prolific. ' ' Mataro (grafted) is not very satisfactory; it bears heavily, but many die during the hot summer. Thos. Casalegno, Evergreen. Zinfandel on St. George, vigorous ; coulures. Mondeuse on Riparia, fair vigor and crop. St. Macaire on Riparia, 9 years old, rocky soil, light growth, fair crop. Carignane on Riparia, 10 years old, good growth and crop. Carignane on St. George, 10 years old, clay soil, good growth and crop. Carignane on St. George, 10 years old, gravel soil, good growth, but coulures. Mataro on St. George, 7 years old, coulures. Mataro on Riparia, good growth and crop. Alicante Bouschet on St. George, 5 years old, strong growth, coulures. Palomino on St. George, 7 years old, clay loam, good growth and crop. Chasselas on St. George, 7 years old, clay loam, good growth and crop. ALAMEDA COUNTY. Grau & Werner, Irvington. Tannat on Lenoir, 13 years old, healthy growth, but very light crop. SANTA CRUZ COUNTY. E. E. Meyer, Wrights. Valdepenas, 7 years old, and Green Hungarian, 6 years old, grafted on St. George, are growing vigorously, but the crops are not altogether satisfactory. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 133 Summary of Reports from Growers. VARIETY. Vigor. Crop. Zinfandel on St. George Good 5 Poor 1 Good 1 Fair 4 Zinfandel on Riparia Poor 1 Zinfandel on Lenoir _ Good 2 Fair 2 Carignane on St. George Good 3 Good 2 Fair 1 Carignarie on Riparia Good 2 Good 2 Carignane on Lenoir Good 1 Good 1 Alicante Bouschet on St. George Good 3 Good 1 Fair 1 Alicante Bouschet on Lenoir Good 1 Good 1 Petite Sirah on St. George Good 1 Poor 1 Good 2 Petite Sirah on Lenoir Good 1 Poor 2 Good 1 Fair 1 Mondeuse on St. George Good 1 Good 1 Mondeuse on Riparia Fair 1 Fair 1 St. Macaire on St. George Good 1 Good 1 St. Macaire on Riparia Fair 1 Fair 1 Valdepenas on St. George Good 1 Fair 1 Durif on St. George Good 1 Good 1 Mataro on St. George Poor 1 Good 1 Fair 1 Mataro on Riparia Good 1 Good 1 Burger on St. George Good 2 Poor 1 Good 2 Burger on Lenoir Good 2 Good 2 Palomino on St. George Good 2 Good 2 Poor 1 Palomino on Lenoir _ Good 2 Good 2 Johannisberg Riesl. on St. George Good 1 Poor 1 Johannisberg Riesl. on Riparia Good 1 Fair 1 Semillon on St. George Good 1 Good 1 Semillon on Lenoir Good 1 Good 1 Colombar on St. George Good 3 Good 1 Fair 1 Poor 1 Colombar on Riparia Good 1 Good 1 Colombar on Lenoir Good 1 Good 1 Green Hungarian on St. George Good 1 Fair 1 Grenache on St George Good 2 Good 1 STOCKS FOR THE FRESNO REGION. In 1903 five plots of resistant vines were planted in the neighborhood of Fresno on land kindly placed at our disposal for that purpose by various growers. The great importance of the raisin and wine industries in the upper San Joaquin Valley, and the special climatic and soil conditions of that region, make it very necessary that we should, as soon as possible, obtain some reliable information regarding stocks that will succeed there. European experience can be relied on less in this region than in the coast valleys. No part of France resembles the San Joaquin Valley, and in the parts of Spain which show the most nearly similar conditions the problems of resistant stocks are hardly more advanced than in California. The five plots were planted primarily to determine the vigor of the most promising stocks in the region, and to provide cuttings for dis- tribution to enable growers to make tests on their own places. The following varieties, which include nearly all those which have given the best results in Europe, were planted : Pure American Varieties. 1. Riparia Gloire de Montpellier. 2. Riparia Grande Glabre. 3. Rupestris Martin. 4. Rupestris St. George. 5. Berlandieri Ress6guier No. 1. 134 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. America- American Varieties. G. Riparia X Rupestris 3306. 7. Riparia X Rupestris 3309. 8. Riparia X Rupestris 101 14 . 9. Riparia X Berlandieri 33E. 10. Riparia X Berlandieri 34B. 11. Riparia X Berlandieri 157 11 . 12. Riparia X Berlandieri 420A. 13. Rupestris X Berlandieri 219A. 14. Rupestris X Berlandieri 301. 15. Solonis X Riparia 1615. 16. Solonis X Riparia 1616. , 17. Riparia X Cordifolia-Rupestris 106 8 . 18. Solonis X Cordifolia-Rupestris 202 4 . Franco-American Varieties. 19. Mataro X Rupestris 1202. 20. Aramon X Rupestris No. 1. As might have been expected, nearly all of these varieties which started grew vigorously in the rich soil of the region. Cuttings were used in making the plantations, and the plots show strikingly the differences in facility of rooting of the different stocks. The Berlandieri and Berlandieri crosses rooted badly. The best of the latter in this respect was the Riparia X Berlandieri 157 11 . The four most vigorous of the stocks were 1616, 1202, 3306 and St. George. All of these in all the plots grew with extraordinary vigor and rapidity. Seven other varieties grew with scarcely less vigor. These were 3309, 101 14 , 1615, Riparia Gloire, 157 11 , Aramon X Rupestris No. 1, and 106 8 . Four varieties, 33E, 34E, 202 4 , and Rupestris Martin grew with fair vigor, but were distinctly inferior to the above. The only varieties of the list which made poor growth were Riparia Grande Glabre, 219A and 301. Stocks for Muscat. The importance of the Muscat of Alexandria, as the basis of our raisin vineyards, makes it highly important that a suitable stock for this variety should be found as soon as possible. The invasion of the raisin vineyards of Spain by Phylloxera is com- paratively recent, and little information is obtainable regarding the use of resistant stock there. In a general way it is stated that the usual resistant stocks are being used in the principal raisin-growing regions of the Peninsula with success. The Muscat of Alexandria is being grown to a limited extent as a table grape in southern France, and is said to succeed on any vigorous stock. On the other hand, in South Africa, Muscat vineyards grafted on Rupestris St. George, Riparia Gloire, Aramon X Rupestris No. 1, and Rupestris Metallica have almost uniformly failed. After bearing several good crops the vines have generally died. No satisfactory BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 135 explanation of this difference has been advanced. The -most plausible seems to be that the vines have been killed by overbearing. The vines, in fact, have borne large crops before dying, and the only stock on which they have remained healthy is Lenoir, which has a tendency to induce light bearing with most varieties. The grafting of Muscats on resistant stocks has been little practiced in California, but a few growers have vines which have been bending several years on various stocks. One grower reports that Muscats on Lenoir, 10 years old, have given fair results; another that they are weak, but bear well. One grower in Tulare County has dug up his Muscat .vineyard grafted on Lenoir because so many of the vines had died. Two growers report that they have Muscats grafted on St. George which have been bearing well and growing vigorously for from 3 to 6 years. Another grower reports that his Muscats grafted on St. George and on Riparia Gloire have given three good crops and are equally vigorous. These results are on the whole encouraging. While the question of the selection of the best stock is not so pressing in the case of raisin grapes as in that of wine grapes, because the greater part of the raisin district is still uninfested by Phylloxera, it will sooner or later be of vital importance to the industry. For this reason a number of test plots have been started, with the cooperation of growers in various sections where raisins are produced. In 1904 Muscat cuttings were bench grafted on the following re- sistant stocks : Rupestris St. George. Riparia Gloire de Montpellier. Riparia X Rupestris 3309, 3306, 101". Solonis X Riparia 1616. Riparia X Berlandieri 33E, 34E, 157". Rupestris X Berlandieri 301A. Solonis X Cordifolia-Rupestris 202 4 . Aramon X Rupestris No. 1. Mourvedre X Rupestris 1202. Lenoir. Several hundred rooted bench grafts on St. George and 1202 were obtained and distributed to a number of growers in various districts, principally in Fresno County. Smaller quantities on the other stocks were obtained and distributed to a more limited number of growers. Notes taken on the quality of the bench grafts before they were distributed were as follows: Muscat on St. George. Heavy growth, complete unions but large swellings. Muscat on 101*. Good growth, complete unions, large swellings. Muscat on 3306. Small growth, complete unions, small swellings. Muscat on 1202. Heavy growth, complete unions, large swellings. Muscat on Lenoir. Good growth, complete unions, small swellings. 136 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Reports have been received from most of the growers who received vines, but they are of little value yet as showing relative vigor of the various stocks. One of the most complete reports is given below, by Dr. W. N. Sherman, Fresno: Muscat on St. George. All grew vigorously. Muscat on Riparia Gloire. All grew vigorously. Muscat on 101 14 . Four out of six lived and made fair growth. Muscat on 3300. Six out of ten lived and grew vigorously. Muscat on 3309. All lived and grew vigorously. Muscat on 1616. Six out of seven lived and grew vigorously. Muscat on 33E. All lived, but made poor growth. Muscat on 202 4 . Four out of six lived and made fair growth. Muscat on 1202. All lived and made vigorous growth. Muscat on Lenoir. Nine out of ten lived and made fair growth. These vines were planted in overwet soil, and were all more or less injured by early autumn frost. Too much emphasis should not, there- fore, be placed on the fact that some of them died. The other reports show in general that the Muscats on St. George 3306 and Riparia Gloire on the whole made the best growth, while 101 14 and 33E generally made poor growth. The other stocks gave intermediate results. The results the first year are, however, apt to be misleading, even as regards vigor, for some stocks, for example. Berlandieri and its hybrids, are slow starting, but make a vigorous growth later. The question of crop can be determined of course only after several years of trial. GENERAL RECOMMENDATION. Only the pressing necessity of some rules to guide us in our imme- diate plantations will excuse the making of recommendations as to stocks in the present incomplete state of our knowledge of the behavior cf the various stocks in the diverse conditions of our grape-growing regions. The present tendency to plant St. George in all soils and in all localities, however, is undoubtedly wrong, and has led to disappoint- ment in many cases, and w r e already possess sufficient data to enable us to choose something better for many locations. The Rupestris St. George has given its best results in the hot, dry interior on deep soils. It seems to be a particularly good stock for Tokay and Alicante Bouschet under such conditions. Its great vigor seems to promise a diminution of the tendency of the Tokay to sunburn, and the coulure which it produces with many varieties only extends to the production of loose bunches with the Tokay. This looseness of bunch is a distinct advantage with this variety. The coloring and ripening of the Tokay leave nothing to be desired when grafted on St. George. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 137 For a great majority of our soils and varieties the two Riparia X Rupestris hybrids 3306 and 3309 promise to be superior in every way to the St. George. The former for the moister soils and the latter for the drier. The vigor and bearing of all varieties tested on these two stocks has so far been excellent, and they should in most cases replace St. George in all but the hottest and driest deep soils. For the wettest locations in which vines are planted in places where the water stands for many weeks during the winter, or where the bottom water rises too near the surface during the summer the most promising stock is Solonis X Riparia 1616. For moist, rich, deep, well-drained soils, especially in the coast counties and on northerly slopes, the St. George is utterly unsuited. The crops on this stock, in such locations, are apt to be small, and the sugar contents of the grapes defective. In these locations the Riparia Gloire is much to be preferred, and will undoubtedly give larger crops of better ripened grapes. None of the above stocks give good results, as a rule, in very compact soils. For such soils the most promising varieties are 106 8 in the drier, and Aramon X Rupestris No. 1 or 202 4 in the wetter locations. In dry, shallow soils 420A and 157 11 give promise of being excellent stocks. This covers most of the soil conditions which occur in California. The only other cases which demand consideration are the varieties with defective affinity. For these varieties the most promising stock is 1202. This stock makes excellent unions with many varieties which fail on most resistants, and is to be tentatively recommended for Emperor, Ferrara, Cornichon, Muscat, Mataro, Folle blanche, Pinot, Gamay. Gutedel and any varieties which have not given generally satisfactory results on Riparia and Rupestris. These recommendations may be summarized as follows: For average, good soils in most locations 1. Drier soils 3300 2. Moister soils 3306 For special soils 3. Dry, deep, in hot regions and locations St. George 4. Dry, deep, in cooler regions and locations .Rup. Martin 5. Dry, shallow . . 420A or 157" 6. Dry and very compact 10G 8 7. Wet and very compact Aramon X Rup. No. 1 or 202 4 8. Wet, loose 1616 9. Rich, moist, deep, well drained in the cooler localities. . .Rip. Gloire For varieties of defective affinity in good soils 1202 138 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. DESCRIPTION OF THE PRINCIPAL RESISTANT STOCKS. In order to enable the grower to determine the correctness of the labeling of his resistant vines, the following brief description, adapted for the most part from "Les Vignes Americaines" of Prof. L. Ravax and accompanied by reproductions of original photographs, will be of assistance: FIG. 1. Riparia Gloire de Montpellier. One third natural size. Riparia Gloire de Montpellier (Fig. 1). The most vigorous of all varieties of Riparia. Leaves very large, as wide as long; young leaves and tips pale green, canes and trunk thick. Male vine. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 139 Roots well and grafts easily, either as cuttings or in the field. Trunk grows almost as large as the scion. Vines on this stock bear well, and the grapes are large, sweet and early. Riparia Grande Glabre (Fig. 2). Very vigorous, but does not grow so stout as the Riparia Gloire. Leaves large, longer than wide, with an FIG. 2. Riparia Grande Glabre. One half natural size. almost rectangular outline, due to the short terminal lobe and the straight sides. Roots thin, hard and wiry. Fertile vine. Roots well, but does not take the graft so well as Riparia Gloire. Almost equal to Riparia Gloire, but subject to ' ' f olletage. " Folletage, or sudden dying of the vine, is a common fault of the unselected Riparias formerly grown in California, and for this and other reasons 140 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. FIG. 3. Rupestris Martin. One half natural size. the Riparia Gloire is to be preferred to the present or other varieties of this species. Rupestris Martin (Fig. 3). Very vigorous and one of the most robust of the exist- ing stocks. Leaves larger than those of Rupestris St. George, and with a V-shaped petiolar sinus. Canes glabrous, pinkish, long and thick. Roots easily, but is more difficult to graft than St. George. The grafts which grow are very satisfactory and are less liable to coulure than grafts on St. George. It succeeds in drier situa- tions than the latter. Male vine. Rupestris St. George (Fig. 4). Perhaps the most vigorous of all the stocks grown when planted in suitable locations. Leaves small ; the petiolar sinus very open, with a j -shaped out- line. Canes and trunk very thick and robust. This variety roots and grafts with great facility, and grows at least as large as any scion which is grafted on it. Succeeds in any soil except those un- derlaid with an im- permeable or stiff clay subsoil. FIG. 4. Rupestris St. George. One half natural size. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 141 FIG. 4. Rupestris Metallica of South Africa. Rupestris Metallica (Fig. . The best varieties of Riparia and Rupestris give excellent results when they grow under appropriate soil and climatic conditions. Their range of adaptation, however, is comparatively small that is, they are likely to .give unsatisfactory results when planted in locations which differ in any consider- able degree from those which suit them best. This seems to be due in great part to the direction their roots naturally take. Roots of Riparia are for the most part spreading and superficial, and succeed only where sufficient moisture exists near the surface. Roots of Rupestris are, on the contrary, plunging and deeply penetrating, and fail if an impenetrable subsoil prevents their taking their natural posi- tion. Experience has shown that crosses between Riparia and Rupestris have a much wider range of adaptation than either of their parents, owing to the fact that they are capable of forming a strong root system in both the upper and lower layers of the soil. More- over, the best of them retain all the good quali- ties of both parents high resistance to Phyl- loxera, ease of rooting and grafting, vigor and fruitfulness of grafts. The best of these hybrids, according to European FIG. 5. Riparia x Rupestris 3309. One half natural size. 142 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. experience, are those known by the numbers 3309, 3306 and 101 14 . The first two are the most promising in California. Riparia X Rupestris 3309 (Fig. 5). This variety resembles in habit a Rupestris, and the leaves are intermediate between those of the two parents. It has small leaves, which, on the laterals, are rounded and without lobes. The young shoots and leaves are sparingly pubescent, but the rest of the vine is glabrous, and by this character readily distinguished from 3306. The vine is male, and therefore does not produce fruit. Riparia X Rupestris 3306 (Fig. 6). The general habit of this variety resembles also that of a Rupestris, but it is easily distin- guished from 3309 by its strongly pubescent leaves and canes. Male vine. Riparia X Rupestris 101^ (Fig. 7). This variety resembles in habit its Riparia parent more than 3309 or 3306. Its range of adaptation is less than that of the latter, and it is most suited to fairly rich soils, such as those suitable to Riparia. It bears small bunches of small, round, black grapes. Berlandieri Resseguier No. 1 (Fig. 8). The pure Berlandieri varie- ties have all the qualities required in a stock resistance to Phylloxera, ease of grafting, permanency of union, fertility of the scion, adaptation to varied soils except one, that of ease of rooting. From 100 cuttings only 10 to 15 rooted vines are obtained by the usual methods of propa- gation. For this reason this species has never been used to any great extent. Certain crosses of this species with Riparia, however, while retaining the merits of the Berlandieri, possess rooting qualities almost equal to Riparia. They are particularly promising for shallow, stiff soils where the Riparia X Rupestris hybrids might suffer. FIG. 6. Riparia x Rupestris 3306. One half natural size. BTTLLETIN 197. GRAPE CULTURE IN CALIFORNIA. 143 Riparia X Berlandieri 157 11 (Fig. 9). This variety was obtained by crossing a Berlandieri with pollen from Riparia Gloire de'Mont- pellier. It has the habit and leaves of a Berlandieri, and a root system intermediate between those of its parents. It is thoroughly resistant to Phylloxera, and its grafts are vigorous, fruitful, ripen well, and are not subject to coulure. The cuttings root fairly well, and field grafts succeed very well. It produces an abundance of strong canes, but FIG. 7. Riparia x Rupestris 101 14 . One half natural size. these do not ripen well in the cooler localities. It produces medium- sized bunches of round, black, pulpy grapes. Riparia X Berlandieri 420 A (Fig. 10). This variety is perhaps superior to 157 11 . The cuttings root more easily, graft as well, and mature more regularly. It is more suited to bench grafting than the former, and makes vigorous and fruitful grafted vines. Male vine. The Solonis is a hybrid of unknown parentage which resembles in 144 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. its habits a Eiparia. It was at one time much used as a stock, but its resistance to Phylloxera is insufficient. In California vines grafted on Solonis have been so weakened by Phylloxera as to be useless. Its only use is for wet, sandy soils, where it gives good results. The good qualities of Solonis are found in certain of its crosses with Riparia, of which the most promising for California is 1616. FIG. 8. Berlandieri Resse'guier No. 1. One half natural size. Solonis X Riparia 1616 (Fig. 11). This variety is very vigorous, and the cuttings root and graft well. It is sufficiently resistant to Phylloxera, and is to be recommended for sandy and especially wet soils. Vine fertile, producing small, round, black grapes. Eiparia X Rupestris-Cordifolia 106 8 -(Fig. 12). This variety is vigorous and thoroughly resistant to Phylloxera. It is particularly recommended for stiff clay soils which become hard after rain and easily dry out. It is in just such soils that Rupestris St. George and BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 145 Kiparia have often failed in California, and this variety therefore promises to be useful. Vines produce small, round, black grapes. Solonis X Cordifolia-Rupestris 202* (Fig. 12%). This variety is adapted to soils similar to those suited to 106 8 , but resists humidity FIG. 9. Riparia x Berlandieri 157H. One half natural size. better. Prosper Gervais in his report to the Congres International de Viticulture of 1900, at Paris, says: "The varieties 202 4 and 106 8 are especially suited to non-calcareous clay soils; the latter succeed in dry. poor, hot soils, providing they are not too shallow; the former in soils which are both compact and wet." Aramon X Rupestris No. 1 (Fig. 13). This variety is the result of a cross between the vinifera variety Aramon and Rupestris Ganzin. 3 BUL. 197 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. FIG. 10. Riparia x Berlandieri 420A. One half natural size. (Mataro) and a Rupestris. It is, perhaps, the most widely planted of all the American vinifera hybrids. Prosper Gervais describes it as " A stock character- ized by its ex- treme vigor, rapid development, ease of rooting and grafting, and the f ruitfulness of its grafts." It is par- ticularly suited to deep, rich, humid, clay soils, and makes excel- lent unions with all varieties of vinifera. The vine is fruitful, bearing large numbers of small, round, bluish-black The leaves resemble Rupestris, and unlike most crosses contain- ing vinifera, its resistance to Phylloxera is quite sufficient and superior to that of Lenoir. It is very vigorous and roots easily from cuttings. It is somewhat difficult to graft, but when suc- cessful the grafts make good unions and are vigorous and fruitful. Its chief merit is that it succeeds in wet, compact soils, where most other varieties fail. Mourvedre X Rupestris 1202 (Fig. 14). This variety is a cross between the Mourvedre FIG. 11. Solonis x Riparia 1616. One half natural size. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 147 grapes. It is grown extensively in France, Spain, Sicily, Portugal, and Roumania, and has given good results wherever tried. In Cali- fornia its vigor is remarkable, exceeding even that of Rupestris St. George. OTHER VINE DISEASES. Oidium. The cause and treatment of this disease have been dis- cussed in Bulletin 186, and the recommendations in it have been FJG. 12. Riparia x Rupestris-Cordifolia 1068. One half natural size. followed by a large number of growers this year in all parts of the State, usually with success. All of the reported failures which have been investigated have been due either to the incomplete carrying out of the recommendations, or to the fact that the vines 'were suffering from some other cause which had been mistaken for Oidium. 148 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. FIG 12i. Solonis x Cordifolia Rnpi-stris 2024. for its effect on the setting of Sulfuring later, if needed, is a well done. This is true for the whole of the two central valleys and for most of California, except the coast belt subject to sum- mer ocean fog. Definition of a Thorough and Effective First Sul- furing. The first sulfur ing should be made when the shoots are between 6 and 15 inches long. It should be done in such a way that every part of every leaf of every vine in all parts of the vineyard re- ceives some sulfur, and the whole vine- The most common mistake of those who have attempted to follow the directions of the bulletin has been a failure to treat the vines thoroughly or rapidly enough in the begin- ning of the season. It can not be too strongly urged that the most effective way to con- trol the mildew is by a thor- ough and effective sulfuring in the beginning of the season. This alone will in most parts of the State keep the vines free, and the sulfuring during the blossoming is needed only the fruit, and as an extra precaution. proof that the first two have not been FIG. 13. Aramon x Rupestris No. 1. One half natural size. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 149 yard should be gone over in as short a time as possible. This will be a thorough sulfuring. To be effective, it must be followed imme- diately by two or three days of warm weather. Unless this happens, the sulfuring should be repeated as many times as are necessary until the proper weather conditions are obtained. FIG. 14. Mourvedre x Rupestris 1202. One half natural size. Mysterious Dying of Vines ("Anaheim Disease"}. The vine, like most plants, especially fruit trees, which are cultivated on a large scale, is subject to diseases of more or less intensity whose cause is not thoroughly understood. These diseases are (1) caused by parasitic organisms which have so far escaped detection, or (2) what is usually known as ''physiological." Physiological diseases are presumably due to some unfavorable con- ditions. For example, chlorosis, cr the failure of the leaves to develop 150 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. chlorophyll properly, is due to an excess of soluble lime carbonate in the soil, and is intensified by cold, dampness and the susceptibility of the variety. The most serious of these two classes of diseases, which affects the vines, is the Anaheim, or, as it is sometimes called, the California Vine Disease. Notwithstanding that it has been the subject of continuous investigation for over fifteen years its cause is still quite obscure. Even the characterization and detection of the disease are so uncertain that vineyards, which after several years of observation by the most ex- perienced investigators have been pronounced infected, have later been declared free. This has led to such a diversity of opinion that while one expert claims that the disease exists in every vineyard in the State, another would have us believe that no such disease exists at all, and 'that all cases of dying vines can be ascribed to one or other of the recognized vine diseases. Neither of these extreme views seem to explain completely the observed facts. While many cases of supposed Anaheim have proved to be nothing but Phylloxera, root-rot, vine-hopper, drought, etc., there still remain a large number of unexplained cases. In some cases the symptoms are practically identical with those of some of the "physiological" diseases which affect vine diseases in Europe. Typical cases of Eougeot .have been noted in Contra Costa County, of Brunissure in San Joaquin, and of Folletage in Fresno, Kings, and other counties. In Sonoma County the disease of Red-leaf, which has some analogy with Anaheim, has been studied by Mr. 0. Butler. An account of these diseases may be found in Bulletin 168, entitled ' * Observations on Some Vine Diseases in Sonoma County. ' ' In a general way, as these troubles are due to soil and climatic con- ditions which weaken the vine, they are to be combated by cultural methods which tend to invigorate. Shorter pruning, thorough culti- vation, irrigation or drainage, and fertilization will in most cases be effective in curing vines which are not too far gone. Many cases have been brought to the attention of the station during the last two years, in which vines which were apparently healthy the previous year have failed to bud out in the spring, or budded out weakly and very late. The cause, in most cases, seemed to be some injury to the vines during the growing season of the previous year. This cause was in many cases the attacks of vine-hoppers. Black Prince vines growing in Tokay vineyards have very often been killed. This seems to be because the vine-hoppers, having a special fondness for this variety, congregate in large numbers on such isolated vines. Whenever the hoppers are sufficiently abundant to cause the dropping of the leaves in summer, the vine fails ' to ripen its wood properly. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 151 Without mature green leaves the buds and canes do not receive the stores of starch which they need for the new growth in spring, and will either grow poorly the following year or fail to start at all. When a new growth of leaves in autumn follows summer defoliation FIG. 15. Brunissure on Tokay leaves. by hoppers, mildew, or other causes, the effect is even worse. The new shoots which start exhaust what food reserves the vine possesses, and the leaves are killed by the early winter frosts before they have been able to return the supplies they have taken from the canes. Similar, but less severe, effects have been observed following a bad attack of Oidium. 152 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. This starvation of the canes and buds may be brought about in another way, namely, by the production of too large a crop. It is often possible, by excessively long pruning, to cause a vine to produce an abnormally large crop of grapes. The larger the crop the more material it takes from the vine, and if too large, the vine is unable to support it and at the same time lay up reserve mate- rials in its canes and buds. In consequence, an extra large crop is often followed by weak growth in the spring, and a consequent small crop the following autumn. Vines of heavy bearing varieties may even be killed in this way, by repeated long pruning. This fact has been long recog- nized by practical grape-growers. Lately, Professor L. Ravaz, 1 of the National School of Agricul- ture at Montpellier, France, has advanced the opinion that the death of vines, as a consequence of overbearing, is much com- moner than is usually supposed. This overbearing may occur as a consequence of various condi- tions other than long pruning. Some seasons are peculiarly favorable to heavy crops. Cer- tain diseases and injuries induce temporary heavy bearing. What- ever the cause of abnormally heavy crops, Professor Ravaz believes that they may result in the death of vines. This is the FIG. IG. Biaek Knot on 2-year-oid zinfandei. explanation he gives of the death of large numbers of vines in southern France, Algeria, and other countries, and he ascribes our so-called Anaheim disease to the same cause. 1 "Influence de la Surproduction sur la Vegetation de la Vigne," by L. Ravaz, Coulet et fils, Montpellier, 1906. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 153 This is substantially the explanation given of the dying of vines in Santa Clara, in Bulletin 134, which was published before the region was declared infested by Anaheim disease. Whether this explanation is sufficient is still doubtful, though it is rendered probable by the fact that healthy young vineyards are now growing in Santa Clara, on the same soil where vines have been killed by ' ' Anaheim disease. ' ' FK;. 17. Bluck Knot on arm of old vine. Black Knot. This is one of the commonest and most widely dis- tributed diseases of the vine in California. Many specimens are received by the Experiment Station every year, from nearly all vine -growing sections. It consists of peculiar growths, or swellings, usually near the surface of the ground on the upper parts of the roots or the lower part of the trunk. It often occurs, also, on all parts of the trunk and branches, but only rarely on the canes. As a rule it does little damage unless it occurs on young vines, or attacks old vines very severely. Figure 16 is the photograph of 154 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. a young vine very badly attacked, showing a large mass of knots at the surface of the ground, and four on the stem above the surface. Such a vine is almost girdled and could never develop into a healthy plant. Figure 17 shows the appearance of the knot on a branch or arm. In this case the knots could be removed and the vine might recover perfectly^ It is not uncommon to find vines with large masses of knots on all sides of the trunk and on all the arms, which yet make a vigorous growth and produce good crops. When the knots extend all around the trunk of an old vine, however, it may be girdled, and, while it seldom dies, it may become weak and worthless. Various theories have been advanced as to the cause of this disease, but the most com- monly accepted is that it is due to abrupt changes of tem- perature, and especially to autumn frost occurring before the vine has become thor- oughly dormant. This cause alone, however, does not seem to be sufficient to cause the disease. The knots appear only on vines growing in moist places, and especially in sandy soil in the hotter regions. Anything which causes a vine to grow vigorously late in the season and prevents the proper ripening of the wood, renders it susceptible to the disease. In accordance with these ideas, the remedies advocated aim at caus- ing the vine to ripen its wood early and completely. These remedies are drainage of the soil, fertilization with phosphatic manures, longer pruning, raising the trunk of the vine, and removal of the knots. FIG. 18. Coulured bunch of Muscat of Alexandria. BULLETIN 197. GRAPE CULTURE IN CALIFORNIA. 155 Swabbing with lime, sulfate of iron, and other antiseptics has proven useless. Couture of Muscats. The Muscat of Alexandria, from which the bulk of our raisins is made, has a. tendency to drop its blossoms without setting. This trouble is usually known in California by the French term of "coulure," which may be translated "dropping." The first crop is particularly subject to this defect, which is often so serious that a large part and sometimes the whole of the first crop is lost. The trouble has been investigated during the last twenty-five years by a large number of observers, and various causes assigned. Among these causes may be mentioned unfavorable weather, improper prun- ing, fungous attacks, unsuitable or exhausted soil. These causes and others may intensify the trouble, but the primary and essential cause has lately been demonstrated by P. Viala and P. Pacottet, and published in the "Revue de Viticulture." 1 According to these investi- gations the cause of the dropping lies in the peculiar structure of the flower itself. The flowers of most culti- vated varieties of grapes are what the botanist calls * ' per- fect." That is, each flower has the two elements which are necessary for the development of the perfect fruit. These elements are the pollen contained in the anthers and the ovules contained in the pistil. Unless the ovules are fertilized by normal pollen the pistil will not develop into a normal grape berry. There are several defects in the Muscat flower which make this necessary pollination more uncertain than with most varieties, and it is only under the most favorable conditions that the ovules are prop- erly fertilized. In the first place, owing to the shortness of the filaments supporting the anthers, the position of the pollen is such that it may all fall off without reaching the stigma, which is a part of the pistil through which the pollen tube obtains access to the ovule. In the second place, the pollen is not powdery as with most vines, but waxy and with a tendency to cohere in masses. This renders its A B C FIG. 19. (After Viala and Pacottet.) Normal flower of the vine, with filaments as long as the pistil. Defective flower of the vine, with filaments shorter than the pistil. Defective flower of the vine, with abortive pistil. 1 "Sur la Fgcondation Artificielle de la Vigne," Revue de Viticulture, T. XXII, No. 551, pp. 5-10. Paris, 1904. 156 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. distribution by wind and insects much less certain. The pollen grains are, moreover, often imperfect, and most of them are incapable of germination and performing their function, even if they reach the stigma. This is shown when we place the pollen grains in a weak sugar solution. Normal pollen germinates readily in such a solution, but that of Muscat of Alexandria germi- nates irregularly, imperfectly, or not at all. The same result occurs if the pollen is placed on the stigma of any variety of vine. Remedies. - - In regions where this variety has been grown for centu- ries (Asia Minor, northern Africa, Spain) it is usual to plant other varieties having abundant and strong pollen among the Muscat vines. This prac- tice, while not re- moving the trouble completely, may be of use in Califor- nia. It would be well in planting a Muscat vineyard to make use of some of the varieties which have shown their ability to produce abundant and vigorous pollen. The proof of this is regular setting of abundant crops. The pollinating varieties might be planted in neighboring blocks, or, better still, in occasional rows. It is necessary not only that the pollinating varieties should have good pollen, but that they should blossom at the same time as the FIG. 20. Four-year old Muscat of proper form. BULLETIN 197 GRAPE CULTURE IN CALIFORNIA. 157 Muscat. In accordance with the advice of Viala and Pacottet, the pollen of Aramon X Rupestris has been used with success in the hot- houses of Paris for the artificial fecundation of Muscat flowers. This is a resistant stock which produces an abundance of blossoms which are completely staminate, and therefore incapable of producing fruit themselves. Their pollen, however, is extremely vigorous, and causes the fruit of other varieties to set well. The pollen of this variety is collected, dried, and, at the proper time, dusted on to the Muscat blossoms. As this variety blossoms about two weeks earlier than the FIG. 21. Six-year-old Muscat of usual form. Muscat, however, it could not be used for cross-pollination unless the pollen were collected and applied as described, which is of course impracticable in a vineyard. Most of the varieties cultivated in the raisin districts blossom about the same time as the Muscat, and such varieties as Palomino, Perruno, Beba, and Burger, which always set their fruit well, would be suitable for the purpose. Another peculiarity of the Muscat of Alexandria, noted by Viala and Pacottet, is that the stigma of the pistil is covered with a drop of liquid which forms and falls two or three times a day, thus removing pollen grains which may have reached the stigma. A moist atmosphere is, therefore, unfavorable to the setting of Muscat. 158 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. We can control the moisture conditions to some extent by avoiding cultivation or irrigation during and just before blossoming. The air near the ground is moister than that a little higher up, and the practice of pruning Muscats to a low, prostrate stump is unfavorable for this and for other reasons. A Muscat vine, like any other, should have a distinct stem or trunk. This trunk should be smooth and without spurs or scars. This trunk FIG. 22. Low Muscat raised by pruning. makes it possible to plow, cultivate, and hoe close to the vine without injuring the arms and spurs. It facilitates the removal of suckers from below the ground, and holds the bearing wood high enough up to keep the grapes from touching the ground. How high this trunk should be depends on various conditions. A smooth stem twelve inches in length from the surface of the ground to the branching of the arms is sufficient to give the advantage mentioned. UNIVERSITY OF CALIFORNIA PUBLICATIONS. COLLEGE OF AGRICULTURE. AGRICULTURAL EXPERIMENT STATION, BERKELEY, CALIFORNIA. THE GRAPE LEAF-HOPPER. BY H. J. QUAYLE. BULLETIN No. 198. (Berkeley, Cal., July, 1908.) SACRAMENTO: w. w. SHANNON, : : : : SUPERINTENDENT STATE PRINTING 1908. BENJAMIN IDE WHEELER, Ph.D., LL.D., President of the University. EXPERIMENT STATION STAFF. E. J. WICKSON, M.A., Director and Horticulturist. E. W. HILGARD, Ph.D., LL.D., Chemist. W. A. SETCHELL, Ph.D., Botanist. EL WOOD MEAD, M.S., C.E., Irrigation Engineer. (Absent on leave.) LEROY ANDERSON, Ph.D., Dairy Industry and Superintendent University Farm. M. E. JAFFA, M.S., Nutrition Expert, in charge of the Poultry Station. C. W. WOODWORTH, M.S., Entomologist. R. H. LOUGHRIDGE, Ph.D., Soil Chemist and Physicist. G. W. SHAW, M.A., Ph.D., Agricultural Technologist, in charge of Cereal Stations. GEORGE E. COLBY, M.S., Chemist, in charge of Agricultural Chemical Laboratory. RALPH E. SMITH, B.S., Plant Pathologist and Superintendent of Southern California Pathological Laboratory and Experiment Station. Whitticr. A. R. WARD, B.S.A., D.V.M., Veterinarian and Bacteriologist. E. W. MAJOR, B.Agr., Animal Industry. H. M. HALL, M.S., Assistant Botanist. H. J. QUAYLE, A.B., Assistant Entomologist. Whittier. W. T. CLARKE, B.S., Assistant Horticulturist and Superintendent of University Extension in Agriculture. JOHN S. BURD, B.S., Chemist, in charge of Fertiliser Control. C. M. HARING, D.V.M., Assistant Veterinarian and Bacteriologist. H. A. HOPPER, B.S.A., Assistant in Dairy Husbandry. J. H. NORTON, M.S., Assistant Chemist in charge Fertilizer} Citrus Experiment T. P E OTNT CT B S S., Assistant Horticulturist, \ Stati n - E. B. BABCOCK, B.S., Assistant Plant Pathologist. E. H. SMITH, M.S., Assistant Plant Pathologist. F. L. YEAW, B.S., Assistant Plant Pathologist. H. J. RAMSEY, M.S., Assistant Plant Pathologist,) Southern California Patholog- C O SMITH, M.S., " " " ) ical Laboratory, Whittier. R. E. MANSELL, Assistant in Horticulture, in charge of Central Station Grounds. RALPH BENTON, B.S., B.L., Assistant in Entomology (Apiculture). A. J. GAUMNITZ, M.S., Assistant in Cereal Investigations. RACHAEL CORR, M.^.., Assistant in Cereal Laboratory. HANS C. HOLM, B.S., Assistant in Zymology. P. L. McCREARY, B.S., Laboratory Assistant in Fertilizer Control. F. E. JOHNSON, B. L., Assistant in Soil Laboratory. M. E. STOVER, B.S., Assistant in Agricultural Chemical Laboratory. D. R. HOAGLAND, A.B., Assistant in Agricultural Chemical Laboratory. CHARLES FUCHS, Curator Entomological Museum. P. L. HIBBARD, B.S., Assistant Fertilizer Control Laboratory. M. E. SHERWIN, Field Assistant in Agronomy. W. H. VOLCK, Field Assistant in Entomology. Watsonville. E. L. MORRIS, B.S., Field Assistant in Entomology. San Jose. J. S. HUNTER, Field Assistant in Entomology. San Mateo. D. L. BUNNELL, Clerk to the Director. JOHN TUOHY, Patron, ) Tulare Substation, Tulare. J. T. BEARSS, Foreman, \ J. W. ROPER, Patron, ) University Forestry Station, Chico. E. C. MILLER, In charge, ) A University Forestry Station, Santa Monica. N. D. INGHAM, Foreman, ) VINCENT J. HUNTLEY, Foreman of California Poultry Experiment Station, Petaluma. The Station publications (REPORTS AND BULLETINS), so long as avail- able, will be sent to any citizen of the State on application. OUTLINE. PAGE. GENERAL CONSIDERATIONS 177 Early accounts ; Destructiveness ; Distribution, general, local. LIFE HISTORY AND HABITS 181 OVERWINTERING ADULTS 181 Food habits ; Relation of food to development and activity ; Influence of temperature upon activity ; Proportion of the sexes ; Migrations ; Time they attack the vine ; Do they feed exclusively on the vine ; Habits on the vine ; Copulation and oviposition. THE EGG 3SG Description and appearance ; Where laid ; Number ; Rate of egg laying ; Incubation period ; Percentage of eggs that hatch ; Effect of oviposition upon the leaf. THE NYMPH 102 The hatching process ; First stage ; Second stage ; Third stage : Fourth stage ; Fifth stage ; Moulting ; Habits of feeding ; Transfer 'to other food plants. THE ADULT 19G Time of reaching maturity ; Feeding habits ; Copulation and oviposition ; Activity and migrations ; Activity of the sexes ; Proportion of the sexes ; Differences in coloring; The varieties of the species comes : Proportion of the varieties ; Common name of the insect ; Preferences for different varieties of vines. DEVELOPMENT 200 Length of life cycles ; Number of generations ; Comparisons of development in other localities. NATURAL CONTROL . 202 Climatic ; Parasitic ; Predatory ; Fungous. MECHANICAL CONTROL 203 Blowers and suction ; Torches ; Dry powders ; Sticky shields ; Fumigation ; Sprays and washes ; Screens or cages. FARM PRACTICES 214 Plowing ; Sheeping. SUMMARY 215 LITERATURE . . 217 THE GRAPE LEAF-HOPPER (Typlilocy'ba comes Say.) BY H. J. QUAYLE. GENERAL CONSIDERATIONS. Early Accounts. The grape leaf -hopper was first named and described by Thomas Say 1 in the year 1825. Specimens were taken Fig. 1. Grape leaf showing first indication of injury due to hoppers. The white specks represent where the insects have been feeding. that year from Missouri, and three or four years later it was reported as an important pest of the vine in Massachusetts. Harris 2 in 1841 wrote the first complete account of the insect and fully appreciated 'Jour. Acad. of Nat. Sciences. Phil, iv, 327. 2 Harris. Ins. Inj. to Vegetation, Flint Ed.. 227. 178 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. the injury caused by it, and ever since that time it has occupied a very important place in the literature of grape insects in this country. Harris's account of the insect remained the standard for a long- while, and no very thorough work was done on the life history of the insect until it was undertaken by Slingerland in 1901. x In California it has been reported as a pest of the vine since 1875. The accounts of insects in the "Pacific Rural Press" furnish a fairly good index on the occurrence of injurious species in this State, and the first account there given is in the issue of April 12, 1879. Notices regarding this insect have appeared frequently in Fig. 2. Young grape leaves in advanced stage of hopper injury. These leaves had completely dried up and fallen to the ground in the early spring. Photographed April 20, 1907. the press of the State, as well as other publications, since that time. Brief notices of its occurrence have been printed in the State Horti- cultural Commission reports, and a bulletin on the insect was issued from this station in 1897. 2 Destructiveness. With the exception of the phylloxera, the vine hopper is undoubtedly the most destructive insect pest of the vine in the State. It is more uniformly present than any other insect 1 Slingerland, Cornell Exp. Sta. Bull. 215. 2 Woodworth, Cal. Agr. Exp. Sta. Bull. 116. BULLETIN 198. THE GRAPE LEAF-HOPPER. 179 attacking the vine, and each year in some parts of the State it occurs in very great numbers, and, in such sections, it levies a heavy tax upon the vineyard interests. To give expression to this loss in money value, for example, in one vineyard of about a thousand acres near Madera, the owner estimated that the damage done last year by hoppers would aggregate about $10,000. The grape leaf-hopper belongs to the class of injurious insects that obtain their food by sucking the juices from the plant. Scale insects and plant lice are other well known pests belonging to this same general group, which obtain their food in much the same way that the mosquito sucks our blood. The sharp pointed beak or proboscis of the hopper (Fig. 4) is thrust into the tissues of the grape leaf and the liquid parts extract- ed therefrom. The feeding is done mostly on the un- derside of the leaf, and those leaves around the base of the vine are the ones first attacked. The first indica- tion of their work is a mottled appear- ance of the leaf due to the pale spots formed wherever the beak has been in- serted and the green parts taken out (Fig. 1) . As the feeding continues these spots become more numerous, and this pale yellow color spreads over the entire surface; and finally the leaf turns brown and drops off (Fig. 2). This injury has been observed as early as April or May, and thus the vine from the very beginning of the season is prevented from making its normal growth. As the hoppers increase in numbers the injury increases with the advancement of the season. In midsummer quite a large area about the crown of the vine will show all the leaves pale colored or completely dried up, and, in severe cases, the entire vine is thus affected. This drying up and dropping off of the leaves allows the sun to have free access to the fruit and may cause sunburn. We have seen the fruit thus exposed and badly sunburned as early as the middle of June. The falling off of the leaves prematurely also pre- Fig. 3. The foliage and fruit of the grape is often badly smutted by the excrement of hoppers. The black specks on the above leaf indicate this. 180 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. labrum labium vents the berry from maturing properly since it is in the leaves of the plant that the sugar of the berry is manufactured. The grape thus loses much of its flavor and sweetness, and likewise the char- acteristic coloring, which is so desirable in certain table varieties, is not attained. The fruit, furthermore, is badly smutted by the exuda- tions of the insects, and this serves as a harboring place for the collection of dust and dirt, and for the growth of fungi (Fig. 3). The dropping of the leaves or any interference with their normal func- tions likewise has its effect on the growth of the wood of the vine. The canes fail to ripen normally for the next year's wood, and many of the buds fail to develop in the following spring. The vine may thus be more or less permanently stunted in growth, and even killed in severe cases of Mandibles grape leaf -hopper injury. Distribution; General. The grape leaf -hopper (Typhlocyba comes Say) is a widely distributed native Ameri- can insect occurring in the United States practically wherever the vine is grown. It is frequently notably in- jurious in the grape belts of New York and Ohio, as well as other less important grape sections in this country. In Europe this species is replaced by two other related species, Typhlocyba flavescens and Typhlocyba viticola. The former seems to be the Much en- m0 re 'injurious of the two and occurs throughout all of temperate Europe and northern Africa, while the latter is confined mostly to Italy and the neighboring islands. 1 Local. In California our species is found in practically all of the vine growing sections, but is most injurious in the Sacramento and San Joaquin valleys. In the coast valleys another larger species (Tettegonia atropunctata) is frequently injurious, most commonly during the earlier part of the season. This species appears not to feed exclusively on the vine, and during midsummer and later is \ Maxillae Fig. 4. The beak, or mouth-parts, of the grape leaf-hopper, larged. 1 Mayet's Insectes de la Vigne, 168. BULLETIN 198. THE GRAPE LEAF-HOPPER. 181 distributed over other food plants. During 1907 the grape leaf-hopper was particularly abundant in many of the vineyards about Fresno, and also in the lower part of the San Joaquin Valley around Lodi. LIFE HISTORY AND HABITS. OVERWINTERING ADULTS. During the colder weather of winter the hoppers may be found in large numbers in the leaves or rubbish in the vineyard, or along the bordering roadsides and fences. Where leaves have been blown together in bunches or lodged in weeds or grass over the vineyard or its borders, hoppers will be especially likely to be present during the colder or wet rainy days of the winter season. They will also be found harbor- ing low down along the fences or in the weeds or other growth among the vines. Alfilaria, one of the commonest plants in many California vineyards in winter, forms a close rosette on the ground, and hoppers will be found abundantly under the low spreading foliage of this plant. Food Habits. The grape leaf-hopper feeds on a large variety of plants during the winter season. It will be found feeding chiefly during the warmer days of winter, and resting more or less dormant during the colder or rainy weather. It attacks practically everything that may be growing in the vineyard or vicinity, although a preference is shown for certain plants. Alfilaria is readily attacked by these insects, and where hoppers are numerous the foliage of this plant will be seen to have a pale yellow color as a result of their work. The low spreading foliage seems to offer suitable conditions for the hoppers when they are not feeding, so that they will be found on the underside of these plants almost continuously, regardless of the kind of weather. Burr clover is also readily attacked by the hoppers in winter, as well as rag wee, dock, wild mustard, alfalfa, and several kinds of grains and grasses. They show a preference, however, for such plants as the alfilaria and the clovers as against the grains and grasses. The hoppers that were taken into the laboratory in the early spring invariably died in the course of two or three days if deprived of food. Under the same conditions they were easily maintained upon alfilaria or other food. They were confined in lantern globes which were placed in the open window of the laboratory, so that the conditions as regards temperature and moisture were not very different from that of the vineyard. Hoppers were also confined in lantern globes in the vineyard, but in all cases they died very soon without food, though the more dormant they were the longer they were able to survive. 182 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. Many of the hoppers succumbed to long continued wet weather or other unusual conditions in winter. After about two weeks of almost continuous rain we have counted as many as 700 dead hoppers under a single bunch of alfilaria. This mortality may be partly accounted for because of unsuitable conditions for obtaining food, though the direct effect of exposure to such conditions is probably the more important factor. Relation of Food to Development and Activity. The activity of the insects is dependent primarily upon food and temperature, and the latter largely influences the former. No matter how much nutritious food may be available, if the temperature is sufficiently low they become dormant and are revived only upon the rise of temperature; but once they become active through the influence of a higher temperature, they require food to maintain their activity. Influence of Temperature upon Activity. On the warm days of winter the hoppers are very active and fly up in large numbers before a person as he walks through the vineyard. On the contrary, on a cold or wet day they may only be disturbed by actually moving the object upon which they are resting, and then they will fly but a very short distance, not more than a foot or two generally. It is possible during such days to pick up the leaves, with a dozen or more hoppers resting on the under surface, and place them in a cyanide bottle without disturbing them. They are most active during the warmer portions of the day, from nine or ten o'clock in the morning, when the dew is dried from the leaves, until three or four in the afternoon. Experiments carried on in the laboratory to determine the effect of temperature on overwintering adults indicated that a temperature of 110 F. was nearly always fatal. These experiments consisted in con- fining the hoppers in a double glass vial and heating gradually with artificial heat. A small homo vial was contained within a larger one, and a thermometer extended through the corks of both viate so that the bulb was contained in the center of the inner vial with the hoppers. Cotton was placed in the bottom of this vial to prevent them from coming in contact with the glass when they would fall down. The whole apparatus prevented so far as possible the unequal heating of the sides of the vial as compared with the air in the interior. In some of the experiments, as given in the table below, the tem- perature was first reduced by ice and salt to 30F. or lower, and suddenly raised again to a point at which all the insects were killed. By consulting the table it will be seen that they became dormant at 60 to 65F. and revived again at about 70F. At 80 to 90F. the first BULLETIN 198. THE GRAPE LEAF-HOPPER. of them would be killed by the heat. The optimum temperature under these conditions was between 70 and 85F. The temperature of the room during the experiments was between 65 and 75 F. In most of the experiments it was the ordinary air of the room, as regards humidity, but in some a moist plug of cotton was contained in the vial with the insects, and thus the humidity was considerably increased. The experiments in detail are tabulated below: Temperature Experiments. Date. Experiments . * <-i n 55 a Room Tem- perature Inactive at .._ ~ O ~