UNIVERSITY OF CALIFORNIA. 
 
 AGRICULTURAL EXPERIMENT STATION. 
 
 BULLETIN NO. 70. 
 
 Abnormal Deposits on Vice Leaves. 
 
 On May 14bh a few leaves from a Muscat 
 vine were received from E. H. Loveland, fore- 
 man of the Butler vineyard at Fresno. Mr. 
 Loveland's attention had been attracted by 
 what seemed to be a growth of fungus on the 
 leaves and on one side of the trunk of the vine. 
 He wrote that he had noticed the same thing 
 before, but never in such amount as this 
 season. 
 
 A preliminary examination of the specimens 
 showed that the leaves, though appearing quite 
 healthy in color, were thickly covered on both 
 sides with a whitish substance occurring in 
 irregular masses, and which at first glance 
 might give some suspicion of a fungoid growth. 
 Examined with a hand-magnifier, however, the 
 material was seen to be of dense character and 
 prone to lift from the surface of the leaf in 
 scale-like particles — in fact, in some places, 
 especially where it had extended over the ribs 
 of the leaf, it had divided and partly lifted it- 
 self from the surface as though it had become 
 shrunken and distorted by drying. No features 
 of fungoid growth were discernible. Upon 
 careful exploration with a three-fourth inch 
 objective the marks shown by the hand- 
 magnifier were made more plain, and the 
 whitish masses gave indications of a crystalline 
 structure, manifesting itself in two main forms. 
 The thinner portions were chiefly made up of 
 flattish crystaliizations of arborescent form, 
 spreading out upon the surface of the leaf, and 
 the thicker parts were dense white masses cov- 
 ered thickly with acicular crystals. The whole 
 appearance of the material was that of an in 
 crustation held in place by adhesion and by 
 interweaving of the leaf hairs through it, the 
 latter fact indicating that it had come upon the 
 leaf in a fluid state and had thus taken close 
 hold upon the inequalities of the leaf surface. 
 This being the character of the deposit as de- 
 termined by the microscope, and as no traces of 
 fungoid origin could be discerned, it was evi- 
 dent that the composition of the material, as 
 determined by chemical examination, would 
 be most apt to disclose its source. 
 
 The small amount of material which could 
 be scraped from the leaves, somewhat less than 
 one grain, rendered it impossible to come to 
 perfectly definite conclusions regarding its ex- 
 act nature. 
 
 The original material contained: 
 
 44. 3 per cent insoluble in water. 
 
 55.7 " " soluble " " 
 
 O. the soluble part: 
 
 69.8 per cent was organic matter and water. 
 7.2 " " " soluble ash. 
 
 23.0 " 11 " insoluble. 
 
 The part insoluble in water contained: 
 
 81. 1 per cent of organic matter and loss. 
 18.8 " " ash. 
 
 The part of the original material insoluble in 
 water consists mostly of lime, with a small 
 amount of magnesia and sulphuric acid. A 
 slight residue resembling mica (probably from 
 the dust of the soil) remains after the treatment 
 with acid. Sulphur is present in sufficient 
 quantities to be easily detected when ignited — 
 doubtless from the sulphuring of the vines. 
 
 The soluble part of the original material was 
 Blightly acid. On ignition it blackens, and 
 emits a slight odor of burnt sugar. The pres- 
 ence of a little sugar is also shown by the cop- 
 per test. The soluble part of its ash is strong- 
 ly alkaline and consists largely of carbonate of 
 potath with some sulphuric acid. 
 I The insoluble part of its ash consists chiefly 
 of lime with a small amount of magnesia. 
 
 The general result of this examination would 
 seem to be that the white substance is a saline 
 incrustation of organic salts of potash and lime. 
 Such a deposit might result from the evapora- 
 tion of vine sap itself, but its deficiency in gum 
 and sugar and apparent absence of tartaric 
 acid (judging from the crystalline form of the in- 
 crustation) renders this supposition unlikely. 
 
 Other Specimens. — Another specimen sent by 
 J. S. Do re, of Borden, Fresno county, had all 
 the characteristic marks of the specimen from 
 the Butler vineyard, except that the material 
 was less abundant. A specimen from Hiram 
 Hamilton, of Orange, Los Angeles county, dif- 
 fers in some respects from the Fresno samples. 
 The deposit is much thinner and looks as though 
 drops of thin whitewash had fallen upon the 
 leaf and spread out upon it. It is most abun- 
 dant upon or near the outer edges of the leaves. 
 Examined with the microscope^ the deposit does 
 not show the needle-shaped crystals as in the for- 
 mer cases, but has in3tead somewhat irregular, 
 roundish masses, sometimes contiguous, some- 
 times separated enough to show the green color 
 of the leaf surface beneath them. There is, 
 however, no indication of fungoid form or 
 
growth, but rather of granular formation, pre- 
 sumably an incrustation. The material was 
 not abundant enough to admit of chemical ex- 
 amination. 
 
 A specimen received from G. F. Merriam, of 
 E^condido, San Diego county, resembles closely 
 the one from Orange, Los Angeles county. Mr. 
 Merriam writes: ** You will notice along the 
 edges of the leaves something white — as if lime- 
 water had been thrown upon them." In this 
 sample the thicker line of incrustation along 
 what stems to be the part where most of the 
 liquid would collect by gravitation is a notice- 
 able feature. 
 
 Further Investigation Needed. — We make this 
 prelimiuary statement concerning the nature 
 of these abnormal deposits upon vine leaves, 
 because of the interest which has been awak- 
 ened in them in the localities where they have 
 occurred, and to allay fears which seem to pre- 
 vail that the peculiar appearances are due to 
 the presence of "downy mildew " (peronospora 
 viticola)—& disease of the vine which is prop- 
 erly dreaded. The wide announcement which 
 has been made of the evil occasioned by this 
 fungoid parasite, naturally renders vine-grow- 
 ers alert to detect signs of its encroachment. 
 It may be stated that the " downy mildew" 
 exhibits its presence by marks wholly dissim- 
 ilar to the characteristics of the incrustation 
 which we have described above. It forms 
 "conspicuous white patches " of a fuzzy or 
 downy character, as its common name indicates. 
 These patches may be very small, but their 
 soft, woolly nature is easily detected. As the 
 disease progresses the patches become yellow- 
 ish, then brownish, and finally the portion of 
 the leaf affected exhibits all the marks of dead 
 tissue. Sometimes the leaf is almost wholly 
 covered and shrivels and dies. Microscopic 
 examination shows that the fungus has pene- 
 trated the leaf substance and destroyed it. 
 
 In the case of the incrustation noted above, 
 the material is wholly upon the outer surface 
 of the leaf, merely resting upon it and easily 
 separated from it. Careful examination of the 
 epidermis from which the material has been re- 
 moved does not show any invasion of the tissue. 
 Nor does it appear from the samples received 
 that the deposit, whatever may be its origin, 
 does any injury to the leaf or its functions. 
 Upon this point we desire more information 
 from those who have observed the occurrence 
 and traced its effects. 
 
 We desire more liberal supplies of the ma- 
 terial to pursue investigations which we trust 
 may disclose the origin of the peculiar phenom- 
 enon. We would also be pleased to have all 
 vine-growers whose attention may be attracted 
 by this announcement, examine their vines and 
 send us specimens of anything which may seen: 
 to them to be of the character described. Id 
 many cases serious apprehensions may be allayed 
 by determination of the real nature of what may 
 seem to be threatening phenomena, and even 
 when the matter is serious it is well to be ad- 
 vised of it as early as possible. The University 
 Experiment Station is equipped for such work 
 and its facilities are always at the service of 
 the vine-growers and of agriculturists generally. 
 
 Mysterious Death of Vines. 
 
 An investigation into the causes of the mys- 
 terious decline and death of grapevines at cer- 
 tain points in Southern California has been in 
 progress at the University Experiment Station 
 for several weeks. The work was undertaken 
 to test the results announced last year by rein- 
 vestigation, and because the loss and vexation 
 resulting from death of vines continues in the 
 same localities affected last year. 
 
 Quite a large collection of vines in different 
 stages of decline was secured from the growers. 
 In some cases the vine was almost lifeless and 
 had made but the most feeble attempt to break 
 its buds, in others one cane had made a fairly 
 vigorous start while others did little or nothing; 
 in others still all the buds had thrown out a 
 few inches of very weak cane. Thus we had 
 for examination vines in various morbid states. 
 The examination of this material was also much 
 helped by careful descriptions of the progress 
 of the trouble by the growers and by personal 
 investigation in the field by Mr. F. W. Morse. 
 The results of the examination as to locating 
 the trouble in the vine itself were mainly nega- 
 tive, as was the case last year. Although most 
 careful microscopic examination of the leaves 
 and wood of the affected vines was made, there 
 was no parasite of either animal or vegetable 
 nature found. In fact the tissue of leaf, cane 
 and trunk was found to be perfectly normal, 
 except that there were clear indications of 
 defective nutrition resulting from a stoppage 
 of the sap supply. Why this stoppage occurred 
 there was nothing in the vines themselves to 
 show. In some samples submitted, a part of 
 the sap ducts were partly or wholly closed with 
 gummy material, presumably the result of con- 
 densation of the small sap flow, because of lack 
 of pressure to carry it onward to the nourish- 
 ment of the newer growth, but there was not, 
 on the whole, nearly sufficient obstruction to 
 prevent the flow of sap had the flow been nor- 
 mal. In fact the decapitation of vines in the 
 vineyard showed that there was in some cases 
 very little sap flowing and in others none at all. 
 This checking of the sap flow is not the imme- 
 diate effect of parasite attack and where it 
 sometimes results as a secondary effect, the 
 tissue of the plant shows the disorganization 
 produced by the earlier invasion of parasite 
 growth. In the cases examined this source of 
 trouble was plainly precluded because the tis- 
 sue was normal and healthy, except in the 
 noticeable deficiency in the sap flow. This fact 
 was determined by repeated examination, both 
 of cross and longitudinal sections of the new 
 growth, the younger wood of the spurs, the 
 trunk of the vine and the roots and rootlets — 
 even to the smallest which could be found on 
 the vines sent to us. 
 
 This conclusion is a verification of the results 
 set forth last year by field examinations by Mr. 
 Morse and by micrcscopic investigations in the 
 laboratory — an account of which is given in the 
 Viticultural Report of the University for 
 1S86 (page 176 et seq.) f to which the 
 reader is referred. His conclusion was that 
 there wan nnf.Hinc found that would in- 
 
dicate a true disease which might increase 
 and spread to neighboring vineyards, but that 
 the phenomena were traceable to more or less 
 accidental and local peculiarities of soil, season, 
 moisture conditions, etc., which may not recur 
 and produce similar effects for many years. It 
 is altogether likely that the continued decline 
 of vines observed this year is but the natural 
 sequence of unfavorable conditions prevailing 
 in the winter and spring of 1886. Since the 
 loss has been greatest in districts where vines 
 have been longest cultivated, it is possible that 
 the evil has been aggravated by the gradual ex- 
 haustion of the soil; pointing to fertilization as 
 at least a partial remedy and preventive by 
 enabling the vines to rally from their enfeebled 
 condition, through the recuperation of the 
 root system. 
 
 Remedy for the Anthracnose of Vines. 
 
 A bulletin of the Agricultural Society of 
 France, lately received from Mr. Chas. Joly 
 (president of the Horticultural Society of 
 France), gives the following information on the 
 subject of the treatment of vines for anthrac- 
 nose (" black blight," "sunburn." etc.)— 
 Sphaceloma ampeHnum : 
 
 The viticultural section of the Society of 
 French Agriculturists has decided to render as 
 public as possible the instructions given below, 
 which have been published by the B jreau Di- 
 rectors of the Medoc syndicate under the sig- 
 nature of its president, Mr. N. Johnston, and 
 whose object is to indicate the best means of 
 dealing with the anthracnose of vines. 
 
 The members of the syndicate having re- 
 peatedly tried the application of sulphate of 
 iron (copperas, green vitriol), have obtained 
 satisfactory results, and intend to repeat its ap- 
 plication on the whole of their vineyards. 
 They do not intend to say that this remedv cures 
 
 the evil completely, but they believe that if 
 practiced with care it greatly diminishes its 
 ravages, and they advise the members of the as- 
 sociation to try it. They even believe that 
 where the vine has been most seriously at- 
 tacked, two applications should be made at in- 
 tervals of 10 or 12 days, such treatment having 
 given excellent results. 
 
 The solution to be used should contain at 
 least three pounds of copperas per gal'on of 
 water, to which may also be added two ounces 
 of copper sulphate or bluestone. The solution 
 is best made in hot water, and it should not be 
 allowed to get very cold, so that it may not de- 
 posit a portion of the dissolved substance. 
 
 The application is made with a brush, to the 
 wood of the vine, taking care that all parts of 
 the vine, from the base of the stock to the ends 
 of the canes, are moistened with the solution. 
 The capital point is, however, that at least the 
 wood of the last three years should be well 
 wetted. 
 
 The amount of copperas used is about 45 
 pounds per acre of (long-pruned) vines (on 
 short-pruned kinds, of course, materially less 
 in proportion). 
 
 The application should be made before the 
 vines bud out, since the strong solution would 
 seriously injure the tender foliage. 
 
 Experiments with sulphate of copper alone 
 have also been tried and seem conclusive, but 
 were on too small a scale to be made a rule. 
 The US3 of a solution containing five per cent, or 
 2£ ounces, per gallon of water appeared per- 
 fectly effective; weaker solutions were not al- 
 together satisfactory in their action. 
 
 While it is too late to apply these remedies 
 in California this season, in the precise manner 
 indicated, those noting symptoms of the dis- 
 ease on their vines might try spraying with 
 weaker solutions, in order to check its progress, 
 or at least to prevent its spread to neighboring 
 vines. E. W. Hilgard. 
 
 Berkeley, June 4, 1887.