UNIVERSITY OF CALIFORNIA. AGRICULTURAL EXPERIMENT STATION. BULLETIN NO. 41. The Olive. The olive is attracting a great deal of inter- est in this State and justly so. California is the only State in the Union that possesses a climate suitable for it. Abundant testimony exists to show that that tree will thrive through- out the larger part of California. The greatest point to be made in favor of the olive is, that it will grow in a soil too dry even for the grape vine and too rocky for any fruit tree. The hills and mountain slopes, not tit for the pasture of even a goat, can be made to produce olives. Precisely such will produce the fruit much earlier than the rich valleys, although in the latter the tree will attain a larger growth. The olive will fill the largest gap in our cul- tures, and its sphere is such that it will not encroach on any other culture. It is perhaps not as a great and valuable product for export that the greatest importance attaches to the olive in California, but rather as a food prod- uct for home consumption. It has often been said that the olive is truly the poor man's tree. In a country like California, where a scanty rainfall is the characteristic of many parts, pasturage, and consequently the p oduction of meat and butter, must necessarily be limited, relatively more so as the population increases. The olive can largely supply this growing defi- ciency. It is the richest and most nutritious of all fruits, for upon it and bread alone a man may be sustained so as to perform the hardest of labor. In the Mediterranean region the olive is of such vast importance that a failure of this crop is a public calamity. A few facts and figures will convey the best idea of its financial value. The crop of Italy, for instance, is estimated to be worth about 200,000,000 francs, Southern France 61,000,000 francs; in Spain i ; is variously estimated at from 84,000,- 000 to 100,000,000 francs and in the Ottoman Empire at 24,000,000 francs annually. That both olive oil and pickles of the finest quality can be produced in this State, is a fact not to be questioned, after Mr. Ellwood Cooper, of Santa Barbara, has taken the prize at the Paris World's Fair. Years ago, when the Mis- sion fathers first landed in California, they brought with them two varieties of olives, one of which especially has been propagated, throughout the State, in different localities. Although a most excellent and hardy variety, and, as we have lately learned from Mr, J* PohndorfFs investigations, one of the best Spanish varieties, known by the name of Corne- zueto, it is here, as in Spain, adapted to the warmer parts of the country only. In a cooler climate the maturing of the fruit falls so late in the season, that it interferes sensibly with the blooming of the next. The importance of intro- ducing earlier ripening varieties is, therefore, apparent. Hence it is a matter of congratula- tion that private individuals, as well as enter- prising nurserymen, have begun to import and propagate French and Spanish kinds. At the experimental grounds of the University, we have received, through Mr. PohndorfFs impor- tations, two valuable varieties, the Nevadillo bianco, an oval-shaped olive of medium size, ripening very early, and the Manzanillo, a rather large olive, of more rounded shape, also of early maturity. No less than thirteen kinds are the generous gift of Mr. Rock, of San Jose; while Mr. Gould, of Auburn, a gentleman who has been very active in proving the adaptability of the olive to the foothill regions of the Sierra Nevada, has presented five specimens of the Picholine. This is a very hardy and rapidly growing variety. In addition to these, six varieties have been propagated from seed. While the latter are not sure to develop any- thing valuable, the differences in foliage and habit of growth indicate widely different types. All the kinds have been planted along a road in a soil and exposure well suited to their develop- ment, and we hope before many years to ascer- tain something definite as regards their value. Varieties. As might be expected, a tree cultivated for such a long period of time, has developed numerous varieties. Owing to their great simi- larity many writers upon the subject, among them Gasparin, avoid the study of these varie- ties and give this advice: Cultivate the best variety for your locality, i. e., the one that gives the best oil in the greatest quantity. It seems, therefore, that the best we can do in California is to try a large number of varieties, as it is safe to say that in our diversified cli- mate no one variety will everywhere succeed equally well. Soil. From the experience of the older countries, as well as that of California, it seems that the olive will grow in a great variety of soils; the most important point to be observed being that they shall be warm and well drained. The most striking instance of this kind that I can re- call is from my own experience. Some years ago I brought a few rooted olives to a place in the Santa Cruz mountains. Thev were set out in r the best of soil, in rich and comparatively moist ground. The growth here for two years was almost nothing, although the trees were well attended to. lu March of last year they were removed to different places, some biing planted on a high knoll, where the soil is very sandy but contains considerable lime; others in small pockets on a southeast slope, the soil in this this case being very rich in humus. With the former, small rooted cuttings but a few inches high were planted. In many instances the holes in which they were planted were made in the rock, and the roots spread on almost bare rock. Without any further attention than being hoed to prevent weeds from smothering them, all grew right along, the older ones mak- ing several feet of growth, where they had be- fore made but a few inches. Of the feasibility of setting out such small plants I shall speak later, but desire here to draw the attention to the fact that the locality in question is a com- paratively cool one. This experience illustrates the fact that in different sections the exposure should be different. In a warmer section, such as Winters or Vaca Valley, evidently the southern exposure on a sunny slope is not needed to produce abundant growth. We find thus on Mr. John R. Wolfskill's place, on Putah creek, perhaps the largest trees for their age in the State. Some of these growing on level ground, and 21 years old fiom the cutting, when measured by me several years ago, were over six feet in girth. Propagation. The mode almost exclusively used in Califor- nia is from cuttings, which are set either in the permxnent site or in nursery rows. We quote Mr. Cooper in his treatise on "Olive Culture:" "The common and preferred method is to plant the cuttings taken from trees of sound wood, from three quarters of an inch to an inch and a half in diameter, and from 14 to 16 inches long. These cuttings should be taken from the tree during the months of December and January, neatly trimmed without bruising, and carefully trenched in loose sandy soil A shady place is preferred. They should be planted in perma- nent sites from Feb. 20th to Mar. 20th, de- pending upon the season. The ground should be well prepared, and sufficiently dry so that there is no mud, and the weather should be warm. In Santa Barbara, near the coast, no irrigation is necessary; but very frequent stir- ring of the top soil with a hoe or iron rake for a considerable distance around the cuttings is necessary during the spring and summer. About three-fourths of all that are well planted will grow. My plan is to set them 20 feet apart each way, and place them in the ground butt end down, and at an angle of about 45°, the top to the north barely covered. Mark the place with a stake. By planting them obliquely, the bottom end will be from 10 injhes to 1 foot below the surface." ^ This mode of propagation, especially in a changeable climate, is liable to several objec- tions. One is that the large cuttings often re- main dormant for several years, thus causing an uneven stand. By first rooting the cuttings in nursery rows this, of course, is avoided, but never will so fine a root system, almost equal to that from seedling plants, be developed as by starting the trees from small herbaceous cut- tings. For at least the cooler part3 of the State we do not hesitate in recommending this method: Take from young, growing trees the young tops, when neither very soft nor perfectly hard, hav- ing three to four sets of leaves and cut with a sharp knife below a joint. Put in a little frame with sand. In the course of three to four months the little cuttings will have rooted, and should then be potted in small pots, where they should remain until well rooted. In a few months more they will be found ready to set out. When very warm weather prevails a thin mulching around the little tree may be advisa- ble, but when a moderate temperature prevails a few waterings in a month will be all that is necessary — and even this in only an unfavor- able spring. It should be added that nothing is gained by setting out the tree before the soil is warm, as it will not grow. The trees referred to previously as planted in the Santa Cruz mountains, were propagated in this manner, and have received no irrigation since setting out. Trees raised from such small cuttings re- semble closely young seedlings, and form a beautiful root system. To get cuttings from large truncheons, such as are imported from Spain and other countries, proceed iD the following manner: Cut the truncheons in pieces about 18 inches long, split those pieces in two, put the halves so made into the ground horizontally, with the bark side up, covering with soil four to five inches deep. Let such bed be in a warm, well -drained place, kept moderately moist. In a few months a large number of young shoots will break through the ground. When of suitable size and hardness, as before described, take the cut- tings and treat in the manner previously men- tioned. Growing Olives from Seed. This is a mode little practiced so far in this State, but worthy of adoption. Of course the process necessitates grafting or budding. It is the general practice in France to do this after the tree has formed its main branches, either budding or grafting into these during the month of May or J une. The advantages of seedling stocks over cut- tings are many : First, vigor of the tree, which produces for a longer time, and more regularly; second, its great hardiness and ability to accom- modate itself to the most arid and rocky soil; third, great abundance of horizontal as well as deep-growing roots, especially deep ones, the }attpr enabling the tree the better to resist wind and frost; fourth, a better form in general and easier to develop and guide than that ob- tained from a cutting. The olives should not be planted with the pulp, but must be cleaned of this either by let- ting them rot in a pile or by putting them into an alkaline solution. A simple way to hasten germination is to break the pits, taking care not to hurt the germ. An instrument similar to the nut- cracker has been invented in France which is said to work very well. When the kernels are deprived of their shell, they are steeped in a compost or mixture of cow-dung and sandy soil, and are sown thickly in the month of April. If it is thought too much work to take the kernel out of the pit, they must be soaked in an alkaline solution. The seedling olive grove at the experimental grounds were treated with an alkaline solution of one fourth pound of concentrated lye to the gallon of water. Most of them sprouted the first year, although there were a few stragglers produced the nexs year. Planting the naked kernels gives the quickest result. Without using this artificial means the seeds will remain dormant at least for two years. The failure in growing plants from the olives produced in this State is clearly due to the fact that the common Mission olive has, at least in most parts of the State, but a small percent- age of well-developed germs. This has been observed by Mr. J. R. Wolfskill, of Winters, who told me that he hai broken hundreds of pits without finding a sound germ. Our exper- j lence at Berkeley has been similir, although i the last year's crop showed a larger percentage i than was the case in previous years. Mr. E. Cooper in his treatise speaks of the failure to get any Mission olives to grow from seed, and 1 find upon inquiry that he has also observed the nou development of the qertn. It is n>y belief that other varieties, and perhaps even *ne com- mon Mission, in other localities will be much more fertile. The following facts seem to sub- stantiate this : To obtain more insight in the matter,Mr. C. H. Dwindle obtained for me from Mr. A. S. White, of Riverside, some dried olives, which, upon ex- amination, proved to have nearly 50 per cent of apparently good kernel?. The result of sow- ing was however very small, some five to six per cent only germinating, nevertheless, enough to prove that there is a difference in the fer- tility of the seeds of the Mission olive in differ- ent parts of the State; although, perhaps, the cause may he in difference of variety. There exists in Southern California at leas'; one other variety besides the common Mission -a variety of more straggling habit and with larger fruit. It is generally mixed with the ordinary kind, and not often recognized as being distinct. The percentage" raised from the European seeds of six different kinds was about 15 to 20 per cent. To save considerable work in select- ing olives for seed, they should be put in pure water; all those that sink at once will be found to have the seed wholly or partly developed. In Europe the wild olive is much used for grafting stock; this species is nearly always fertile, and it would pay any one who desires to grow olives on a large scale to get a quantity of its seeds. Time of Bearing It is argued by many people that the olive requires an excessively long time to come into bearing. In favorable localities this is by no means the case. In the southern part of the State, large olive cuttings commence to bear in the fourth year. Mr. Cooper, of Santa Bar- bara, reports two gallons of berries on some of his best trees at that age, and as much as 30 gallons from the best at six years. Mr. Kim- ball, of National City, Sin Diego county, re- ports similar results. Our own experience at Berkeley, when the summer temperature is very low, must be termed very encouraging. Two small trees,buta few feet high, brought from the Mission of San Jose, were planted in' 1873, by Mrs. Jeanne Carr. For two years after Mrs. Carr's departure, they were neglected, but answered very quickly to kind treatment; and after six years from planting produced some fruit, and have produced full crops every two years, steadily increasing. The yield at eight years thus was about 50 pounds; at 10 years over 100 pounds per tree, while this year each tree averaged 225 pounds. In the off years the yield has been about one- quarter as much. Compared with warmer localities, where the Mission olive ripens earlier, the yield perhaps looksj small, but with va- rieties better adapted to our cooler climate the result would doubtless be different. A3 olives are worth four cents a pound the profit would be very good. Judging from what we know about the adaptability of the olive, it would seem that an olive grove would be one of the safest investments all over the State, provided no overproduction should take place. Enemies of the Olive. There are, however, a number of drawbacks, chief of which are the insect peats. So far, with the exception of some twig-borers, the only insect enemy the olive grower has had to contend with is the scale, coupled, however, invariably with the black fungus, which it is now pretty well understood feeds upon the viscid excretions of the scale. So severe has the a tack of this scale been in the moister parts of the State, that only the most persever- ing men, led by Mr. Cooper, of Santa Barbara, have succeeded in its suppression. I do not believe as some do, that the sole remedy for this evil is to leave the coast and seek localities where, owing to the intensely dry air, the olive scale seems to be an impossi- bility. Others factors governing the condition of the tree, and not often considered now, will show themselves. It must be remembered that with the influence of the sea we also lose the more uniform climate which always has been considered of prime importance to the olive. But by stariing with thoroughly clean trees and keeping them so I think there need be no fear. For the purpose of keeping the trees clean from the first, whaleoil soap dissolved in a decoction of tobacco water, viz., one pound of soap and one-half pound of tobacco per gallon, is to be recommended. It is here that the small green cuttings previously described are much to be preferred to old cuttings, which nearly always are more or less infested with scales. Bat the scale is by no means the only formidable enemy the olive grower of the Old World has to con- tend with. The principal ones to bs feared there are the Decus olece, a dipterous insect affecting the pulp of the fruit; the olive moth, Finea oleela, which like the apple moth feeds on the seed of the olive; finally, the Psylla, a hemipferous in- sect. Of these three, the first, Decus olece, is by far the most destructive. According to Pouchet it destroys in France yearly 3,000,000 francs worth of olives; and the other coasts of the Mediterranean do not escape its ravages It seems to breed all the year round. The fly lays its eggs, one to several, in the pulp of the olive, and the larvre when hatched live on the pulp next to the pit. It remains here as chrys- alis, and finally leaves the olive a flying in- sect. Whether it has left the fruit before the harvest, or is crushed with the oil, it is al- most equally objectionable. This insect is la mouche of the French and macha del olieo of the Italians. The olive moth works almost like the apple or codlin moth. The eggs are laid while the pit is still young and tender, the larva living on the kernel of the olive until it leaves it a complete moth, causing the fruit to drop pre- maturely. This insect does not, however, con- fine itself to the fruit alone, but works also on the leaves and bark, causing tuberosities and crippling of the leaves. The Pyslla olece is a hemipterous insect, which like the dreaded white cottony scale, covers itself with a white viscid covering, fas- tening itself on young foliage and fruit. We have called the attention to the existence of these pests just now when large shipments of olive truncheons are imported. It is the duty of every one who receives them to guard against such pests by proper disinfection. For this purpose, I think the vapor of bisulphide of carbon the best. A large dry goods box clothed with tin is easiest to get; for a box five to six feet long and four feet high, a couple of ounces of bisulphide will be sufficient for a charge. In the box place the liquid in a saucer on top of the cuttings, cover the box tightly and leave for half an hour. Berkeley, June 20,1885, W. G. Klee.