UNIVERSITY OF CALIFORNIA. AGRICULTURAL EXPERIMENT STATION. BULLETIN NO. 75. Spray and Band Treatments for the Codlin Moth. During the Bummer of 1887 careful observa- tions have been made of the efficacy of aprayiDg with arsenical compounds and of the band treat- ment for the reduction of the codlin moth, Carpocapsa pomonella. This insect appeared in the University orchard a few years ago, and during last year was quite abundant. The suc- cess reported by Prof. S. A. Forbes, State Ento- mologist of Illinois, in spraying with Paris green for the destruction of the larvae as soon as it begins to feed in the calyx of the apple, and similarly good results reported by several California apple-growers, suggested that a 6et of experiments with arsenic and its con- pounds should be made in the University or- chard, where more time could be given to an accurate account of results than a busy fruit grower could devote to such work. As it was known that W. G. Klee, State Inspector of Fruit Pests, was conducting similar experiments on his own farm and was keeping accounts of experiments by others, it was thought best that the University experiment should be given a direction similar to his, that the results of all experiments could finally be brought together and serve for purposes of a wide generalization. For this purpose Mr. Klee was invited to pre- scribe the applications to be made. He did so, and assisted personally in the preparation and application of the poisons— a service for which we make due acknowledgment. Application was made of three substances, te areenic, Paris green and London purple, and each in different strengths, as will be speci- fied ia the tables which will be given below. The white arsenic was dissolved in hot water; the Paris green and London purple were kept as thoroughly stirred as possible while being drawn up by the pump. The drenching of the trees was quite complete, the spray being espe- cially directed upou the clusters of fruit which in most cases were still upright, eo that the drops of the liquid were caught and held in the calyx end. There was, of course, much differ- ence in the sizsof the fruit, as the orchard com- prises a large collection of summer, fall and winter fruit. Trees were selected, however, as carefully as possible, which had the fruit of the best stage of growth, say from the size of a pea to that of a small marble, at the time of the first spraying. The tables will show. that in most cases three applications were given, all within 30 days from May 3 L During that period the records of the University meteorological observatory show that rain was measured but once, and then but one-twentieth of an inch, and in the month of June there was but a sprinkle, even less in amount, so that the weather was perfect for the retention of the poison on the fruit. The University orchard is planted with two trees of each variety, and in these experiments one was sprayed and the other reserved with cut treatment, so that a comparison, each tree with one of its own variety and age, could be made. The orchard was guarded in such a way that no outside interference could be had with the fruit. Twice a week all the fruit which fell from the sprayed trees and from the j check trees, unsprayed, was examined and care- j ful entry made in a book prepared for the pur- j pose, of all worms found in the fruit, of all fruit from which the worms had escaped, and the number of worms found under the bands of sack- cloth, which were placed upon all the trees. This plan of procedure was faithfully carried out until November 1st, when all the fruit remaining at that time was removed from the trees, examined for worms and the experi- ment closed. The following tables show a summary of re- sults. The full report, with details of proced- ure and deductions therefrom, is reserved for our next annual report. Paris Green— One Pound to 160 Gallons of Water. Fruit. I'tar.. .. Pear Apple... Variety. Da.es of Application. Apparent Effects. Worms in fruit and under bands on treated tree. Worms in fruit' and under bands on un- treated tree. 10 4 4 23 Miy 3d and 19th, and on e later. May 3d and 19ih, and June 1st. . Gain, per cent . 18 71 62 Paris Green-One Pound to 320 G*lons of Water. Pear Pear 'ear Apple.. . Apple.. . 3 1 6 0 0 8 27 1 1 4 Duchess Oldenburg May 3d and 19th, and June 1st. . May 3d and 19th, and June 1st. . Gain, per cent . . . 19 J4 41 Paris G een— One Pound to 160 Gallons of Water, with Two Pounds of Soap. Fear. . . . Apple.. . Apple.. . Bjurra Urii d'niver .... May 31 5 3 1 2 3 13 Duchesse Mignonne,. .. Gain, per cent 9 50 18 London Purple-One Pound to 160 Gallons of Water. I'ear.. . . Pear . . . Apple. . Apple.. 13 4 9 5 21 0 9 7 St. Michael Archangel.. May 3d ar.d 19th, and June |»t.. May 3d and 19th, and June 1st' . •Strength of second anil third sprayings, 1 lb. to 220 galls, water. Gain, per cent 3L 37 London Purple— One Pound to 80 Gallons of Water. Pear.... Pear Pear Apple. . *Str» May 3d and 17th,* and June Isc* May 3d and May 18th* Fruit and folage dama^eu Fru.tand foliage damaged Fruit and foiiag. d una^ed 19 0 0 16 6 24 4 51 jugi.h of second and thin Gain, ptr tent «5 59 86 White Arsenic -One Pound to 320 Gallons of Hot Water. Pear — iQallebasae Monstreuse . Apple.. . Grimes' Golden Pippin. May 3d and 19th Foliage li.tle damaged 1 I 3 • White Ars«-nic-One Pound to 480 Gal'ons of Water. I'tar.... Apple... I : | 1 1 17 White Arsenic— One Pound to 640 Gallons of Water— with Soap. Pi ar. . . . Apple.. . l i 1 o I No check • These applications were all made to effect the lirat brood of the moth. The figures of in- fested fruit are all small, for in B;rkeley, as in moat places along the coast, at least, the first brood of the moth wa9 unusually small this year. This fact would not necessarily interfere with the percentage of gain by the treatment. In the case of the white arsenic the record of worms is so small and the result so contradictory in that the stronger wash gave a percentage of loss while the weaker gave a percentage of gain, the inference is that the worms were not on hand to be killed. Undoubtedly allowance must be made for chances of this kind in all ex- periments including only a tree or two. One codlin moth is said to deposit anywhere from 50 to 200 eggs, and so a single moth by presence or absence might produce a great difference in an experiment. When the peat is abundant there is of courae leas danger of such results. The experiments with Paris green and Lon- don purple are more satisfactory, as more trees are included, and worms are found on all, which shows that the moth visited the trees more freelj*. The percentages of gain muat be con- sidered very satisfactory, and the stronger ap- plications, barring injury to foliage, produce the best reaulta. In tne case of Paris green, the application of a wash with one pound of Paris green toJOO gallons of water must be regarded as very satisfactory, giving a gain of over 70 per cent of good apples and p^ara and not do- ing any injury to foliage or fruit. The sus- ceptibility of tress to injury seems to vary with the kind of fruit and the variety as well, and may be affected by other conditions. This is a matter which needs full investigation. Examination of the Band Treatment. In order to determine some points about the efficacy of banding apple and pear trees for the de8truction of the larva? of the codlin nnth, an accurate record haa been kept in the Univer8ity orchard during the pa8t season. The bands were put on eariy and consisted of strips of old sacks. The strips were five or six inches wide; the ends were allowed to lap well and the band was secured by a string tied around near the center so as to furnish crevices at both the upper and lower edges, to accommodate worms coming from either direction. All these bands were removed on a certain day each week, the larvre counted and killed and the bands replaced. At the same time all the fallen fruit wa3 gath- ered, examined for worms, or to see if worms had escaped, and records of these facts kept sep- arately. The full statement of this investiga- I *lor is not yet ready, but a brief summary of leading results may be given as follows: I Row No. Pears g. *$< 14- 15- 16. :s 16. 17. 18. 19. 20. 21 . , 22. 23- 24 . Larvae Larvoe Other So. under in damaged trees bands. fruit. fruit. in row • 3i 27 7i 22 • 42 58 142 35 42 127 37 • 125 34 180 38 . 56 34 "5 38 . 137 34 226 39 . 83 54 226 38 19 95 15 l 9 *7 . 9< 48 202 32 • 57 14 102 25 . 89 89 446 24 . 163 61 320 26 83 40 153 25 • 32 22 81 21 . 74 31 191 16 . 3 0 8 9 1188 608 2704 457 This summary shows that while 2704 apples and pears were found from which worms had escaped, there were found under the bands but ' 1188, or 44 per cent, the remaining 56 per cent includes worma which found nesting- places elsewhere or perished. The assistant, who kept the record of this experiment, assures me that he believes many of these were eaten by birds which were always working over the ground while he was in the orchard. The others must have concealed themselves under clods to spin their cocoons, for there is no loose bark on the trees, and no rubbish or fences in which they could hide. It would seem from this experiment that the bands catch less than half of the worms which gain accea8 to the fruit, and yet the destruction of this proportion of fully fed and healthy larvae must be considered very satisfactory. As all the losses by birds or other enemies of the worm by accident and by other agencies which destroy insect life must be taken from the percentage of worms not found under the bands, it will be seen that the old method of treatment is still one of the most effective that can be employed. E. J. Wickson. Berkeley, Nov. 19, 18S7. Difficult Fermentations. Complaints of difficult fermentations have been V6ry general during the vintage just past, and a great deal of red wine especially has re- fused to "go dry" within the usual or any rea- sonable limit of time. It has long been my conviction that in the vast majority of cases the difficulties complained of arise from excessive heat during and particularly at the beginning of ler mentation. At tne end of last year's vint- : i age, a number of comparative fermentations! were made at the University Viticultural Lab- oratory, partly with a view to testing this question; but it being late in the season, the only grapos available for the purpose, viz., setf-! ond-crop Zinfandel, were not of a character tot test the point, having high acid (.65) and low sugar (21.6); and the high temperature at- tained seemed to accelerate, rather than re- tard, the fermenting process. This season, 16 fermentation experiments, parallel with those of last year, have been made, and the results of some of these throw so much light upon the causes of " difficult fermentations" that it seems proper to give publicity to them in ad- vance of any detailed report on the whole se- ries. Equal charges of 200 pounds each were fer- mented in 50-gallon tanks, save that in the hot ferments tions 25 pounds mere were used, in order that the rise of temperature might be favored by greater mass. In the hot chamber a temperature of between 85 and 90 degrees was maintained; while in the fermenting-room in which the other charges were being treated, the temperature was kept as nearly as possible at 75 degrees. The grape employed was a fine lot of Carignane, courteously donated for the purpose by A. J. Salazar Jr., of Mission San Jose. The must showed 25.75 per cent by spiudle, and .53 per cent, or a little over five pro mille, of acid. Of the tacks in the fermenting-room, filled with mash at 63 degrees, three, treated by usual methods, went practically dry and were sent to press on the seventh day; the first to finish being the one with " floating cover and twice-daily stirring," the method adopted in the laboratory for general purposes. The high- est temperature reached by any of these was 95 degrees. On that day (7th) the two tanks in the hot chamber, which had in setting been warmed up to 86 degrees and at first fermented most violently, an.; in 4.'> hours attained a maximum tempera- ture of 106 degrees, had come down to very slow movement; the actual solid contents were found to be a little over 12 per cent. It being obvious that they would not ''go through" un- der existing conditions, the two charges were divided into four parts, of which one was left in the hot chamber and treated as before, in or- der to observe the outcome. The others served lor experiments to test the best mode of reviv- ing the fermentation in the lower temperature of the fermenting-room. Oae portion received IJ per cent of pomace, freshly pressed from one of the other tanks, and well stirred in; floating cover put on and well stirred three times daily. Fermentation soon revived, aud went on slowly, but steadily, until the seventh day, when the charge was sent to press, practically dry. Oae, a double portion of 19£ gallons, was mixed with 2^ gallons of cendensed Zinfandel must set at 21 per cent with distilled water, and having been allowed to nass into active fermentation before mixing with the " stuck ' r mash. Fermentation soon set in, and slowly but steadily carried it to dryness on the 17th day, being eight days from the time the fresh must was added. The fourth portion was left without any addi- tion, but was from the time it left the hot chamber vigorously aerated, by means of an air pump, three times a day. Fermentation soon revived, and the charge went dry and was sent to press at the end of the sixth day from the time it was removed from the hot chamber, be- ing nearly two days in advance of the other tanks treated with pomace and must respect- ively, but aerated only by ordinary "foulage " with a cross-peg stirrer. It thus appears that simple aeration, without the addition of any ntw yeast, was at that stage of the mash that had M stuck " in consequence of overheating, the most effectual mode of reviv- ing and completing the fermentation. The pressed wine had the same acid-percentage as the orginal must, and is free from acetic taint. As for the portion that remained in the hot chamber, it continued a feeble action for some time, but on the 14th day from the set- ting of the nush it had practically stopped. It was then removed to the fermenting-room, and after cooling down to 75 degree3 and aerating by the pump, a faint revival of fermentation took place for 36 hou T s. Then the cap sank and the tank was " dead." The day after, the odor and tastoof milk-sourness became so patent that the mess was sent to press with over nine per cent of solids, aa a dead failure, on the 17th day; a woful, but in practice but too familiar exam- ple of the results of hot fermentations. I reserve for the future a detailed discussion of the subject, in connection with other experi- ments, but the main points illustrated may be briefly thus stated: 1. While musts of low sugar contents and high acid may be successfully rushed through to dryness at a high temperature and make a sound wine, the same is not true of those hav- ing high sugar and low acid; the margin of dif- ference between the two cases is a very narrow one, both as to temperature, acid and sugar, and hence a few days of hot "norther n may easily turn the scale. 2. When the temperature has not been ex- cessively high, and not maintained too long, simple aeration by means of a pump or blower may revive it at a lower temperature. Sound pomace, or fresh fermenting must, are addi- tions to be used when available or neceBsary. While-these facts and principles are not new to experts, I have thought it worth while tore- establish them by facts and figures, and to offer them as a substitute for the supposed mysteries of "difficult fermentations" that have so vexed our winemakera. The vatting of hot and overripe grapes and the omission of proper aeration of the mass, while allowing the surface to acetify, are responsible for nine- tenths of all unsoundness in California wines, E. W. Hilgard. Berkeley, Nov. 17, 1887.