UNIVERSITY OF CALIFORNIA PUBLICATIONS. COLLEGE OF AGRICULTURE. AGRICULTURAL EXPERIMENT STATION. DIRECTIONS FOR SPRAYING FOR THE CODLING-MOTH. By C. W. WOODWORTH. BULLETIN No. 155. (Berkeley, March, 1904.) SACRAMENTO: w. w. shannon, : : : : : superintendent state printing. 1 904. 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. E. JAFFA, M.S., Assistant Chemist. (Foods, Nutrition ) G. W. SHAW, M.A., Ph.D., Assistant Chemist. (Soils, 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. H. TWIGHT, B.Sc, Diplome E.A.M., Viticulturist. E. W. MAJOR, B.Agr., Animal Industry. A. V. STUBENRAUCH, M.S., Assistant Horticulturist, in charge of Substations. WARREN T. CLARKE, B.S., Assistant Field Entomologist. H. J. QUAYLE, A.B., Assistant Entomologist. H. M. HALL, M.S., Assistant Botanist. GEORGE ROBERTS, M.S., Assistant Chemist, in charge Fertilizer Control. ('. A. TRIEBEL, Ph.G., 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 FORRER, Foreman, \ J. E. McCOMAS, Patron, Pomona, \ J. W. MILLS, Superintendent, Ontario, >■ Southern California Substation. JOHN H. BARBER, Assistant Superintendent, Ontario, ) A. A. KNOWLTON, Patron, ) t tt r.^T „ v „r , • f University Forestry Station, Chico. J. H. OOLE 1 , Workman in charge, ) ROY JONES, Patron, ) ..... urTTTrnrn „ t University Forestry Station, Santa Monica. \\M. S1ILTT, Foreman, \ II. O. WOODWORTH, M.S., Foreman in charge, 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. DIRECTIONS FOR SPRAYING FOR THE CODLING-MOTH. The present bulletin has been prepared for the purpose of placing in the hands of growers of apples and pears a concise statement of the recommendations for the control of the codling-moth, based on the results of the investigation of this insect conducted the past season in the Pajaro Valley. This work was undertaken at the request of the Orchard Association, with funds provided by the Boards of Supervisors of Santa Cruz and Monterey counties. The detailed discussion of the results of these studies will be presented in a series of bulletins, which will be sent on application to those especially interested. We hope that the present publication will also enable us to secure the co-opera- tion of growers in every section of the State in making the observations suggested herein, so that a more complete knowledge may be obtained of the facts upon which the rational treatment of the insect must be based. ARSENICAL SPRAYS THE REMEDY. There have been a great many suggestions as to different ways of controlling the codling-moth, and all that have come to our attention, that offered any prospect of even partial results, have been tested and found wanting, with the single exception of the arsenical sprays. Possibly, at some future time, some other effective means may be discovered that will be as good, or better than the arsenicals, but up to the present time these substances stand far in the lead, and it is not wise for the orchardist to experiment, except on the smallest scale, with anything else. That any of the standard arsenicals constitute an effective remedy appears to be well demonstrated, for in every part of the Pajaro Valley apple district, in which we conducted experiments, it was found possi- ble to reduce the injury to a very satisfactory percentage when the poison was properly applied. Which Arsenicals to Use. Paris Green. — The material which has been most widely used for fighting this insect is paris green, and for effectiveness against the insect none of the other arsenicals are any better at the same strength of arsenic. The amount most commonly used and found very satisfactory is one pound for one hundred and fifty gallons. There are a good many localities where paris green is liable to injure 4 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. the tree, and this injury can easily be greater than any possible saving of fruit effected by the destruction of the worm. Not only will it result in small apples, but, if too severe, may also affect the crop of the following season. In most of these regions the danger of injury can be avoided by the addition of lime. The amount added to the spraying mixture should be the greater the more susceptible the trees are to injury. The regions in which the trees are most liable to injury are those where dews and fogs are the most prevalent. Five or ten times as much lime as paris green is the proportion recommended in these more moist regions. Lime Arsenite. — In the lower portion of the Pajaro Valley the dan- ger of poisoning the foliage is so great, even when the maximum amount of lime is added, that we can not recommend the use of paris green at all, but suggest the substitution of the lime arsenite, or lead arsenate. Lime arsenite may be made according to either of the two following formulas: The Taft Formula: Boil one pound of (white) arsenic and two pounds of lime in two gallons of water for forty minutes, and then dilute as required. One pound of the arsenic, prepared as above, is used in every three hundred to four hundred gallons of water. The Kedzie Formula: Boil two pounds of white arsenic with eight pounds of sal-soda in two gallons of rain water. Boil these materials together in any iron pot not used for other purposes; boil them fifteen minutes, or until the arsenic dissolves, leaving only a small muddy sediment. Put the solution in a two-gallon jug and label " Poison — Stock Material for Spraying Mixture." The spraying mixture can be prepared whenever required, in the quantity needed at the time, by slaking two pounds of lime and adding this to forty gallons of water; pour into this a pint of the stock arsenic solution; mix up, stirring thoroughly, and the spraying mixture will be ready for use. Either of these mixtures when carefully made is almost or quite as effective against the worm, and distinctly safer to the foliage, than paris green. The cheaper cost of this material and the greater ease of keeping it mixed while spraying are advantages that partly offset the trouble of preparing it. Arsenite of lime is very satisfactory where one can buy it already prepared and is assured of the honesty and careful- ness of the manufacturer. When buying it in this form there is usually no gain over paris green in the matter of cost, and often it is really the more expensive. Lead Arsenate. — r J^he arsenate of lead is by all odds the safest of the arsenicals that have come; into use as regards their effect on the foliage. It appears to be also distinctly less fatal to tin; codling-moth than the DIRECTIONS FOR SPRAYING FOR THE CODLING-MOTH. same relative strength of paris green, or of arsenite of lime. There are two methods of making this arsenical. In each method 68% arsenate of soda is used, and with this, in one case, the ordinary white granular acetate of lead, and in the other, lead nitrate. The process of manu- facture is as follows: The lead salt and arsenate of soda are dissolved separately, and then poured into the tank containing the water for spraying. The proportions used are about as follows: For every ten ounces of arsenate of soda take twenty-four ounces of lead acetate or twenty ounces of lead nitrate. These substances can be purchased in the right proportions and tied up in bags, so that it will require one bagful of each for each tank of water. From the results obtained the past season we would recommend the use of a mixture containing distinctly more arsenic than if other arsenicals were used; or the amounts given above for each one hundred gallons. As a precautionary matter, it might be well to test the mix- ture in order to be sure that the arsenic is all in combination; this can be done by the use of po- tassium bi-chromate, which will produce a yellow pre- cipitate if the solution con- tains lead in excess, as it should. Paris Green, Oil and Lime. — A new spraying mix- ture was developed last season too late for a test in the orchards sufficient to be positively recommended, but it promises to be the best solution of the problem of preventing injury to foliage by paris green. This con- sists in coating the particles of the paris green with an infinitesimal quantity of oil, which will prevent its being wetted by fog or dew, thus rendering it almost absolutely harmless to the plant. The spray mixture may be made as follows: Stir one pound of paris green into a pint of crude oil (petroleum); slake four or five pounds of lime; add the paris green and oil, and stir well, so that the lime will unite with the excess of oil; then dilute to one hundred and fifty gallons, and it is ready to apply. This mixture will be tested very thoroughly the coming season. Fig. 1. Microscopical appearance of spraying mix- tures, showing one sphere of paris green and many particles of lime. 6 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. WHEN AND HOW TO SPRAY. These are questions that each orchardist must in some measure answer for himself, for no precise statement can be made that will cover any large region, or possibly any two succeeding years in the same orchard. There is enough difference in the problem of controlling the codling- moth, even in the single horticultural region, the Pajaro Valley, to require an essentially different program in its different parts. Doubt- less other sections of the State will require still greater differences in the method of handling the codling-moth than are necessary in the region that was under investigation. All the spraying operations should be made to depend upon data determined for each region as to certain essential facts in regard to the history of the codling-moth and of the trees. These facts are not difficult to obtain, and there is no reason why any grower of apples might not make the necessary observations to determine the proper time for these spraying operations. Under the worst conditions there will be the necessity for making three campaigns each season against the insect. In many regions one or two of these might be omitted. How much can be omitted and the times for the beginning and end of each campaign, will have to be determined for each locality. THE FIRST CAMPAIGN. The first campaign is the one based upon the blossoming of the trees. There is a short period, just immediately after the petals fall from the fruit, when it is possible by properly spraying the trees to place suffi- cient poison within the cup formed by the calyx lobes to effectively destroy any worms that may thereafter attempt to enter the apple at that place. Most recent reports on the codling-moth have dwelt with much emphasis on the necessity of properly timing this application; and our observations have indicated additional grounds for its efficiency, par- ticularly the ascertainment of the fact that the young worm, on attempt- ing to enter an apple at this place, regularly spends a considerable period within the cup, feeding upon the surface of the fruit, but not injuring it in any appreciable way. During this time the presence of a small amount of poison would be almost certain to be destructive to the insect — its death being brought about before it enters the fruit; and so the apple will be protected. The important point to determine, in order to make these sprayings effective, is the exact time when the first blos- soms have dropped their petals (as the beginning of the first spraying period) and the time that these first blossom-cups have sufficiently closed to make this spraying ineffectual (as the end of the first spraying DIRECTIONS FOR SPRAYING FOR THE CODLING-MOTH. period). During this period there should be a thorough application of the poison, in order to fill these early blossom-cups. There may be a few varieties in some localities, in which all the blossoms open nearly enough together so that practically everything is accomplished by a single spraying. In most parts of the State, however, the blooming of all varieties extends over a considerable period of time, during which it will be necessary to make two, or even three, applications, in order to accomplish this result; for instance, at one time blossoms and fruit were picked from about the same part of one apple tree, representing all the stages of development shown in Fig. 2. It will not do, as is often .recommended, to wait until the majority of the blossoms are in about the right condition and then attempt to make one spraying accomplish the work. In one instance, where we made a definite determination of the blossoms setting on an apple tree, every blossom that finally produced fruit had already passed the con- dition in which it was possible to place poison in the cup before the major- Fig. 2. Blossoms and Fruit on tree at one time. ity of the blossoms on the tree had dropped their petals. It would certainly not do, as has been recommended, to wait until practically all blossoms had fallen, because, at least under the conditions prevailing in the Watsonville district, the fruit setting on the trees may have attained considerable size, as in the case just cited. There is almost always a con- siderable difference in the average time of blooming of the branches in the top of the tree from those near the bottom; so that, if it could be ascer- tained that in any region only the early blossoms on the branch would produce fruit, still more than one application would have to be made to effectively treat the higher and lower fruit. Only in those regions where the conditions are such that this first campaign can be omitted entirely, will the neglect of carefully deter- mining the time of blooming fail to result in loss. The method of spraying in this first campaign should be essentially different from that later in the year in this particular, viz., that the object is to poison the blossom-cup. It will be a waste of energy to spray anywhere except against the blossoms from above. It is only the spray which comes down into the blossom that can have any effect* 8 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. There are two methods of accomplishing this: First, the nozzle may be held in such a position that it will be directed down over the blos- soms and the spray mixture applied with considerable force; the inten- tion being to thoroughly drench these parts of the plant from above, so as to cause the poison to lodge among the hairs covering the whole interior of the cup. The other method is to throw the water into the air, above the blos- soms, in a fine mist, the actual direction of the nozzle being of little Fig. 3. Spraying outfit in operation. consequence. The fog thus produced is allowed to settle gently on the parts which it is desired to wet and the spraying kept up until every- thing has been completely wetted. This will require a much longer time, but is probably somewhat more economical in material; either method will accomplish the results aimed at, viz: the poisoning of the blossom- cup. The aim of most of the sprayers whose work has been studied is to attempt to wet the fruit from beneath; indeed, this mistake is practically universal among California sprayers. In a very few cases elevated plat- form- are used (something like that shown in Fig. 3), from which it is DIRECTIONS FOR SPRAYING FOR THE CODLING-MOTH. 9 We desire to secure the co-operation of orchardists in all parts of the State in making observations upon the blossoming time of the different varieties of apples and pears in each section. Blanks like the following will be sent to any who will volunteer in this work. BLOSSOMING RECORD To Determine Date to Spray for Codling-Moth in First Campaign. Name of observer Address Location of trees under observation Variety FIRST SPRAYING. Date of first blossoms 1904. Mark a number of blossoms by tying a bit of white yarn loosely around stem of blossom. Date of petals falling 1904. Spray before cups close. Actual date of spraying 1904. Date of cup closing 1904. Per cent of blossoms open at last date per cent. SECOND SPRAYING. Mark a number of blossoms just opening at last date above, using red yarn. Date of petals falling 1904. Spray before cups close. Combine with second campaign, if moths have begun to emerge. Actual date of spraying 1904. Date of cup closing 1904. Per cent of blossoms open at last date per cent. THIRD SPRAYING. Mark a number of blossoms just opening at last date above, using blue yarn. Date of petals falling 1904. Spray before cups close. Combine with second campaign, if moths have begun to emerge. Actual date of spraying 1904. Date of cup closing 1904. Per cent of blossoms open at last date per cent. If there are any buds still opening, mark some with brown yarn. Should there be more than five per cent of buds still to open, continue these records on the other side of this sheet. After the fruit has set make the following observations: Number Marked. Number Set. Marked with white yarn _ Marked with red yarn Marked with blue yarn _ _ Marked with brown yarn Send this record, when complete, to C. W. WOODWORTH, Agri- cultural Experiment Station, Berkeley, California. DIRECTIONS FOR SPRAYING FOR THE CODLING-MOTH. 11 possible to properly spray the tree. In other cases where trees are very small a few operators have learned to spray into the air entirely, instead of toward the tree, and using long extension rods so that the spray will be carried to the top of the tree A nozzle giving a fine mist can of necessity only force water a short distance. The best results can only be expected when much attention is given to both the time and method of spraying. THE SECOND CAMPAIGN. The second spraying campaign should be inaugurated at about the time when the first eggs are being deposited upon the trees. In some localities this may not be far from blooming time, but in others, as at Watsonville, it is considerably later, and different in the different parts of the valley. The actual time of egg-laying can be quite accurately determined by the fruit-grower without very much difficulty. The eggs themselves are quite small — not larger than a pin-head — and flat and transparent, so that one would have to look at them in such a way as to get the proper reflection of light from their surface in order to clearly distinguish them from the leaf or fruit on which they lie. They will be first found in the spring upon the upper side of the older leaves, and by careful search in the orchard the time of egg-laying might be deter- mined by direct observation of the egg. A much simpler method, however, requiring no careful examination of the trees, can be made by means of a breeding cage; a common Mason fruit jar with a piece of cloth tied over the top, in the place of the ordinary metal cap, will be very satisfactory. This can be kept in the orchard in an old apple box, tacked to the north side of a tree, making a sort of a cupboard, in which the breeding cage may be placed to protect it from the weather and accidents. The codling-moth passes the winter in a great variety of situations, sometimes in the ground, or it may be in cracks of the bark or under bands of cloth, if these have been placed on the tree according to the method so commonly in vogue. The insect is in the worm-form during the winter just as it was when it left the apple, but has covered itself with a tough silken cocoon, and lies almost quiescent in this form until spring. During the winter these cocoons may be sought for and placed in the breeding cage, and the insects will go through their transformation in the spring and appear as moths in a perfectly normal manner. Now, by examining these breeding cages from week to week, the orchardist can determine the date of the first hatching of the moths, the time when they are produced in the greatest number; and if he 12 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. begins spraying as soon as this hatching occurs and continues it, say- once every three weeks until they cease to appear in numbers, he can be confident that he has properly timed his spraying for the destruc- tion of the brood of worms to be produced from the eggs laid by these moths. If the moths hatch practically all together, as they may in some regions, a single spraying is all that is necessary for this campaign. Fig. 4. Cupboard containing breeding cages. In most regions, however, this will not be found to be the case, and two, or possibly three, sprayings may be necessary. Again, in some localities the first and second campaigns, as just outlined, may occur so close together that the same spraying will poison the leaves and outer surface of the fruit for the young worms, and fill the blossom-cups so as to be ready for those that enter these cups before feeding elsewhere. The method of spraying in this second campaign differs from that already described in that the object now becomes not to wet any one part of the tree particularly, but to cover everything as uniformly as DIRECTIONS FOR SPRAYING FOR THE CODLING-MOTH. 13 We desire to secure the co-operation of orchardists in all parts of the State in making observations on the time the codling-moth emerges in the spring in each section. Blanks like the following and envelopes to contain specimens will be sent to any who will volunteer in this work. EMERGENCE RECORD To Determine Date to Spray for Codling-Moth in Second Campaign. Name of observer Address Location of breeding cage Number of cocoons placed in breeding cage The breeding cage may consist of a " Mason fruit jar" with a piece of cloth over the top instead of the screw cap. Obtain the pupae during the winter from old apple boxes, about the packing-house, under bands or in cracks in the bark. Tack an apple box on the north side of a tree as a cupboard to contain breeding cage. Examine each week. When first moth appears record it below, and continue records weekly. Date. FIRST SPRAYING. Found moths. Put them in envelope 1. If time to spray blossoms again, also spray foliage for young worms. Found moths. Put them in envelope 2. Ii three weeks since last spraying and ten per cent of the cocoons have produced moths, spray at once. Found moths. Put them in envelope 3. If you did not spray last week or week before, do so now. Actual date of spraying , 1904. SECOND SPRAYING. Found moths. Put them in envelope 4. If three weeks since last spraying, spray again. Found moths. Put them in envelope 5. If three weeks since last spraying and if envelopes 4 and 5 have as many moths as envelopes 3 and 4, spray again. Found _ moths. Put them in envelope 6. If three weeks since last spraying and envelope 6 has as many moths as the average of the others, spray again. Actual date of spraying , 1904. THIRD SPRAYING. Three weeks from the second spraying, unless the number of moths falls lower than the average of preceding weeks. Found moths. Put them in envelope 7. Found moths. Put them in envelope 8. Found moths. Put them in envelope 9. Found moths. Put them in envelope 10. Found moths. Put them in envelope 11. Actual date of spraying , 1904. Send the record when complete and the envelopes, for the accurate identification of moths, to C. W. WOODWORTH, Agricultural Experi- ment Station, Berkeley, California. DIRECTIONS FOR SPRAYING FOR THE CODLING-MOTH. 15 possible with the spray mixture. Moreover, the surface which we now desire to wet is waxy in large part, instead of being hairy. It is not possible, therefore, to accomplish good results by the use of a nozzle giving a coarse heavy spray, as may be done in the first spraying. There now arises, also, the danger of over-spraying; that is, of spraying so long in the same place that the fine, mist-like particles which were first quite uniformly distributed over the leaf will ultimately run together, often leaving large areas of the smooth waxy surface of the leaves entirely free from water and from poison, and concentrating the poison that is deposited from the larger drops of water along the edges of the leaves or in the wrinkles occurring along the veins, the greater part of the leaf being free from poison. For this purpose, therefore, a nozzle should be selected which will spray widely and produce the finest separation of the particles of water. Such a nozzle will only force the water a short distance, and the mist formed will float in the air if a gentle breeze is blowing, making it somewhat difficult to spray on the tree except on the windward side. If the trees are large there will be so much advantage in an elevated platform and extension rods, enabling one to reach into any part of the tree, that such appliances should always be used. It is well to attempt to spray from all directions, the object being to cover the tree as thoroughly as possible, but not to drench any portion; stopping long before the leaves begin to drip. If one has a fine nozzle, or a bunch of small nozzles at the end of the rod, and moves over the tree rapidly, it can be made very thoroughly wet in every part before enough liquid is used to produce this unsatisfactory "over-sprayed" effect. During the past season it was observed in the Watsonville district that a great majority of the worms entered the fruit at other places than the blossom end, and when this is the case the second campaign will become much more important than the first. In other regions, according to the testimony of many investigators, the reverse is true, in which case the first campaign would evidently be the more important one. But even in these regions undoubtedly the second campaign would produce good results, because everywhere a certain proportion of worms entered at other places than at the blossom end, even while the fruit was small. 16 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION. THE THIRD CAMPAIGN. The codling-moth has more than one brood in all parts of California where apples and pears are grown on a commercial scale, and in most localities the injury produced by the first brood is insignificant in com- parison with that coming later in the year. In the Pajaro Valley par- ticularly, the orchardists would not consider the codling-moth an important insect but for this later work. The varieties grown in this region almost invariably set such an amount of fruit that heavy thin- ning is necessary, and the little that has been injured by the worms up to thinning time is removed in that process. If this thinning is done before many of the worms have left the fruit and the apples removed are properly disposed of, it can not but have a beneficial effect in reduc- ing the number of parents for the next generation. Under the conditions occurring in this valley all the work of the first two campaigns is directed primarily toward preventing the laying of a large number of eggs for the midsummer generation. The third cam- paign is the most important one, and would be the only important one but for the fact that the majority of the insects killed by a spray in this section are killed only after the worms have marred the fruit. Their work is often supposed to be done by the little green beetle with black spots (Diabrotica soror) and does not really injure the apple for use, but is very objectionable from a commercial standpoint, since the fruit is no longer of first quality. Very few worms will be able to develop in fruit which is kept poisoned from midsummer until fall, but the fruit may be badly marked by the entrances just alluded to. It will not do, therefore, in most localities to neglect the earlier campaigns, even though the third is the most important. The method of spraying is the same as in the second campaign, but the foliage becomes more susceptible to injury late in the season, both because there may be an accumulation of poison in the leaves from earlier applications, and from the fact that older foliage is less resistant to the poisonous action of arsenic* The sprayer should look for evi- dences of injury and, if necessary, change to a less injurious arsenical. *Arsenic poisoning is of two sorts : the acute and the chronic ; the former is more common on young foliage in the spring when grossly careless methods have been employed, and consists in the sudden dying and drying up of the edge of the leaf, or of the whole leaf, as though killed by heat, and is quite appropriately called "burning." The chronic poisoning is very gradual in its action, and resembles the normal ripening of the leaf in the fall. It is hardly distinguishable from the effect of drought, or the injury by a sap-sucking insect, and is most likely to show itself where the tree or branch is already suffering from one of these other troubles. When using the lead arsenate there is very little danger from this source, and possibly the new paris-green-oil-lime mixture may be a complete preventive. With other arsenicals care must be observed toward the end of the season. DIRECTIONS FOR SPRAYING FOR THE CODLING-MOTH. 17 We desire to secure the co-operation of orchardists in all parts of the State in making observations on the time of pupation of the first brood of codling-moth larvae in each section. Blanks like the following and envelopes to contain specimens will be sent to any who will volunteer in this work. PUPATION RECORD To Determine Date to Spray for Codling-Moth in Third Campaign. Name of observer Address Location of orchard Number of bands Put bands around a number of trees and examine them each week. Provide a tight tin box to contain specimens. As soon as you find worms beneath the bands put them in the tin box, noting hereon the date and number of worms found. Keep the box in the cupboard pro- vided for observation of the second campaign. The next week before going around to examine the bands, see if any of the worms in the tin box have transformed into brown pupse; kill them by puncturing with a pin and place in envelope A, the next week in envelope B, etc. t.. Number of Pupae t?„„^i^™ Number of Worms taken from Date - in Box. envelope. Bands and put in Box. B Spray now unless you have sprayed within three weeks, and repeat in three or four weeks' intervals as long as pupae continue to appear in the box. c D E F G H I J K L M O Actual dates of sprayin: Send this record, and the envelopes containing specimens for accurate identification, to C. W. WOODWORTH, Agricultural Experiment Station, Berkeley, California. DIRECTIONS FOR SPRAYING FOR THE CODLING-MOTH. 19 The time to begin the sprayings of this campaign can be deter- mined by the use of bands. These have been widely used as a remedy for the codling-moth, but are not effective enough to be of much value; we could not see that the use of bands accomplished enough to warrant their use as a supplementary measure in connection with spraying. We are not yet ready to condemn their use in this way, and can com- mend them as an index to spraying operations. When the spring generation of worms is full grown, they leave the fruit and seek a place in which to go through their transformations. If there are bands on the tree, enough will select this place to give a good idea of the general condition of the brood. After spinning their cocoons the worms soon assume the pupa con- dition and are then somewhat spindle-shaped and brown in color, and in a few days they come forth as perfect moths ready to lay eggs for the second generation of worms. Within a couple of weeks from the time the first pupse are discovered the orchard should be well poisoned, if not very recently sprayed, for the late worms of the first generation. This should be repeated often enough to keep everything poisoned to the end of the season in the fall. Apparently the season ends at quite different dates in different years, for often the eggs of the moth will be found very abundantly on the apples at picking time, and the same variety may in another year be quite free from eggs. This is probably because the conditions causing the hibernation of the worms became effective earlier in the season. When the conditions favoring hibernation are present, the worm simply becomes quiescent within its cocoon, instead of transforming into a pupa, and may pass half the year in this stupor. As soon as this occurs, which we will know when pupse cease to be produced, the season's fight against the codling-moth may be considered at an end. THE YEAR'S SPRAYING PROGRAM. The foregoing account may seem, at first sight, to be very complicated, but when applied to the conditions obtaining in most localities will at once simplify itself. For instance, in the coldest localities there may be but one brood, in which case no summer pupae will be produced and the third campaign disappears. Here, also, the blossoms may open almost simultaneously, making the first campaign consist of a single spraying. The first generation of moths may also come out with the blossoms, so as to require nothing additional. Where it is a little warmer the moths may come out later, requiring one spraying in both first and second campaigns; but the moths remain one-brooded, so that the third campaign is barred out. If they become double-brooded, then probably the smallest number of sprayings will be two in the spring and one in midsummer. 20 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. In the still warmer locations, the number of sprayings will increase,, until perhaps as many as three or four in each campaign may be needed. It is impossible to give specific directions for each locality until sufficient data have been obtained by making the observations through a series of years, as indicated in this bulletin. RESUME. The codling-moth was found controllable by the use of arsenical sprays in every district studied. Paris green is highly satisfactory, wherever it is safe to foliage, but in some localities may have to be replaced by lime arsenite or lead arsenate; or, possibly, the new formula of paris green, oil, and lime may prove best. The fight against the codling-moth may be divided into three cam- paigns; the timing of each must be determined for each region. The first campaign is intended for the poisoning of the calyx cup of the apple, and requires spraying from above and more than one appli- cation, if the blossoms are not uniform in time of opening. The second campaign is timed by the appearance of the moth in the spring, and requires a method of spraying different from that of the first campaign, the idea being to cover every part of the leaf and fruit with the poison. The third campaign is for the later worms, and the times of beginning and closing this attack are determined by the production of pupae, from which moths will hatch that season and lay eggs for another brood of worms. The danger to foliage by the poison is greatest during this campaign. Orchardists are solicited to aid the Station in its further study of the insect, by making observations in their own localities of the facts upon which the timing of the applications in each of these campaigns must be based.