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.