THE CODLING MOTH OK APPLE WORM.
By A. L. QUAINTANCE, In Charge of Deciduous Fruit Insect Investigations, Bureau of Entomology,
INTRODUCTORY. No insect enemy of fruits, with the possible exception of the San Jose scale, iá more generally and effectively treated than the codling moth or apple worm, and its control has become one of the routine features of work in many commercial orchards. The treatment for' this insect mostly takes the form of spraying the trees with arsenicals, and great variation is possible in the thoroughness with which the work may be done. Some orchardists are able to reduce the amount of . wormy fruit to a very small percentage of the crop, but the major- ity perhaps fail to obtain best results on account of imperfect spray- ing and lack of attention to details. In many instances results have been so unsatisfactory as to lead orchardists to doubt the value of the measures recommended, and some hold that these are entirely without merit* While a large amount of fruit is thus needlessly lost through careless spraying there is a still greater aggregate loss in the thousands of small orchards over the country, often of not more than two or three dozen trees, in which spraying is not practiced, the owners not being informed regarding the value of such work or the orchard interest not appearing sufficient to warrant the necessary expense. Notwithstanding the considerable amount of spraying at present practiced against the codling moth its injuries still continue to be very great, resulting in an estimated shrinkage in the value of the apple crop of the United States of approximately $12,000,000 annually; and if account be taken of the expenses incurred in its control for labor, arsenicals, and spraying apparatus an additional sum of prob- ably not less than $3,000,000 or $4,000,000 must be charged to the presence of this insect in the apple orchards of the United States. More thorough and timely spraying where the practice is already established and the adoption of such work where heretofore neglected w;ill result in a great lessening of the present heavy loss suffered from this pest. CHARACTER OF INJURY. Wormy apples (see PL LIII, figs. 1 and 2) are familiar to all grow- ers and consumers of this fruit, and many have seen, on cutting open an apple, the small, pinkish larva about three-fourths of an inch long, the cause of all the mischief. Injury is done only in the larval or 436 436 YEARBOOK OF THE DEPARTMENT OP AGRICULTURE.
worm stage of the insect, the larva spending the greater portion of its life within the fruit feeding on the substance of the apple, render- ing it more or less worthless and always of inferior grade. Infesta- tion is generally indicated by a mass of brown frass protruded from the calyx end or elsewhere, marking the place of entry of the larva. The effect of the injury will vary according to the degree of ma- turity and the variety of apple attacked. Injury by the first genera- tion of larvae to the green fruit in early summer will cause most of it to fall, and wormy apples comprise a considerable proportion of the so-called " June drop." With some fall and winter varieties fruit injured early in the season may remain on the trees, especially if the injury has not been serious. Later appearing larvœ, as of the second generation, do not cause serious dropping of fruit, though the extent of this will depend much on the amount and violence of the wind. The injury, however, will, exoept when occurring quite late in the season, cause the fruit to ripen prematurely. Thé ammmt of depreciation in the value of the fruit will vary according to the character of the injury. Apples which have been penetrated to the core and in which larvœ have fed until full grown are practically valueless, except for purposes of cider or vinegar. Fruit with only a slight surface blemish on the sides oi* ends is injured mostly in keeping qualities and in appearance, and may have con- siderable value for ready sale, though it would not be suitable stock for placing in cold storage. In the Middle W^tem ^nd Eastern States especially, considerable fruit which is more or less injured by. the codling moth finds its way into barrels with first-class stock, greatly depreciating the value of the latter. More care is necessary in grading to exclude all wormy fruit, as it often happens that the poor- est and not the best fruit in the package determines its market value. lilFE HISTORY AND HABITS. Since the time of Cato the codling moth has been writt^u about by practically all entomologists, and the combined literature on this species, from nearly all countries of the world, would amount to sev- eral good-sized volumes. Nevertheless, it is only within compara- tively recent years that a fairly complete account of the life and habits of the insect has been presented, and beliefs formerly current have been shown to be erroneous.** At the present time numerous impor- « Special mention should be made of the work of Doctor Howard (Rept. Com. Agrie. 1887, p. 88) ; Card (Bui. 51, Nebr. Agrie. Exp. Sta., 1897) ; SUngerland (Bui. 142, Cornell Univ. Agrie. Exp. Sta., 1898) ; Gillette (Bui. 31, n. s., Div. Ent, U. S. Dept. Agrie, 1902) ; Simpson (Bui. 41, Div. Ent, U. S. Dept Agrie, 1903) ; Bau (Bul. 95, Utah Agrie. Exp. Sta., 1906) ; Melander & Jenne (Bui. 77, Wash. Agrie. Exp. Sta., 1906) ; and of Professors Washbum, Aldrich, Cooley, Oordley, Pettit, Woodworth, Lloyd, Sanderson, and others, who have all coor tribute^ la our preeeait knowledge of the insect, and method« of control. THE CiÖDLINö ïtf^TH OB APPLE WOKM. 437 tant points in the biology and treatment of the codling moth need further investigation in various parts of the country to secure data on its behavior under varying seasonal and climatic conditions. The question of the number of generations of the codling moth in dif- ferent portions of the United States has not been accurately deter- mined, especially in the South and Southwest. The great importance of the insect as an apple pest warrants the fullest investigation of these and other points. - The codling moth, like all insects of the order Lepidoptera, or but- terflies and moths, to which it belongs, presents four distinct stages in its life, namely, the egg^ the larva or worm, the pupa, and the adult or parent moth. THE EGO. The egg of the codling moth is disk-like, somewhat oval in shape, and about the size of a pin head, the shorter diameter varying from 0.96 to 1 mm. and the longer from 1.17 to 1.32 mm. On the surface is a network of lines which becomes coarser toward the flange-like margin. The eggs are glued tightly to the foliage or fruit, appearing under reflected light as a glistening white spot. The egg stage was fully described in 1893. Until about ten years ago the idea gen- erally prevailed that the eggs were deposited either in the blossom end or the stem end of the apple, since the entrance holes of the larvae were usually found at these places. Professor Card in 1897 found that the eggs of the first generation of moths were laid mostly on the foliage, and similar observations were made by Simpson in Idaho in 1901-2, and these conclusions have been fully verified by other workers. In oviposition the moth seeks a smooth place, as the upper surface of a leaf, the pilose or downy condition of the young fjruit at this time rendering it unsuitable for egg-laying purposes. Moths of the second brood, on the other hand, deposit the major- ity of their eggs on the fruit, which by midsummer and later is smooth and more conspicuous. The distribution of the eggs over the plant has an important bearing on the question of the insect's control, as will be pointed out in describing the habits of the young larva. The number of eggs deposited by one female has not been definitely determined, the records (incomplete in some instances) of moths in confinement ranging from 21 to 85. The maximum num- ber under orchard conditions is thought to be not over about 50. Ovi- position probably occurs mostly in the late afternoon or early even- ing, or, according to some writers, at night. The period of incubation will vary considerably, depending on temperature conditions, and eggs are deposited at different stages of embryonic developments Eggs laid by first-appearing moths of the spring generation are usu- ally subjected to a lower mean temperature than those deposited by this generation several weeks, later. Observations by Simpson oil the egg stage under orchard conditions show this to vary between 438 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. nine and eighteen days, with an average of about eleven days. Other observers have found it to be somewhat less, though the observations were made mostly with eggs under indoor conditions.
THE LARVA. It is in the larval or " worm " stage only that injury is done. At the time of hatching the larva is of a whitish or yellowish color, measuring fron; one-twentieth to one-sixteenth of an inch in length. The head is proportionately large and shiny black. The cervical and anal shields are dark, and the body is dotted with regularly arranged tubercles, each with a short hair or seta. When full grown the apple worm measures about three-quarters of an inch (19 mm.) in length; the body is of a pinkish flesh color above, becoming whitish below, the general color varying from pinkish to much lighter. The head is brown with darker markings and varies in width from 1.54 to 1.76 mm. The cervical and anal shields are much lighter. There are 3 pairs of well-developed thoracic legs, 4 pairs of fleshy abdominal, and a pair of anal prolegs. (See PI. LII, fig. 2.) The young larvœ, upon hatching from eggs placed on the leaves, at once begin their search for the fruit, and a variable time will elapse before this is reached, depending upon its proximity and abundance. Simpson notes instances where eggs were deposited 10 to 20 feet from the fruit, and it is questionable if in such cases the larvae would find the fruit before succumbing to destructive influences. When hatched upon foliage; it is stated « that the larvae feed upon this before the fruit is found, though more data upon the leaf-feeding habits of the larva under orchard conditions are desirable. This leaf-feeding habit, however, has been frequently observed with larvae in confinement. It is thus possible, by poisoning the foliage, to destroy the larvae just after they have escaped from the egg and before they reach and injure the fruit. Larvae from eggs placed on the fruit at once—or upon finding the fruit, if from eggs placed elsewhere—seek a place to enter, as at the calyx, or less, usually at the stem end, or some roughness on the surface, or where two apples are in contact or touched by a leaf. The greater part of the first-brood larvae enter the apples at the calyx end either between the lobes or by boring through these at the base. Numerous workers have investigated this point, and the larvae of the first brood entering the fruit at the calyx end are stated to be from 60'to 80 per cent. Careful counts by Simpson in 1901 gave an aver- age of 83 per cent with a minimum of 79 per cent, and more ex- tended observations during the following year gave a maximum of
o Bul. 51, Nebr. Agrie. Exp. Sta., p. 18 (1897) ; Bui. 222, Mich. Agrie. Bxp. Sta., p. 90 (1904) ; Bui. 131, N.H. Agrie. Exp. Sta.; p. 22 (1907). THE COPLING MOTH OR APPLE WORM. 439
93 and a minimum of 50, the average being 81 per cent. According to the same investigator less than one-half of 1 per cent enter at the stem end, the remainder going.in on the side. These figures are very important in connection with the fact that the young larvse feed within the calyx cavity for a few days before boring into the interior. This permits of their destruction by spraying into the calyx cavity, while the lobes are still open, a dose of poison to be eaten with their first meal. Upon arriving within the calyx cavity the larva begins to feed and a few days later, as is true when the fruit is entered at the side, eats its way to the center, where it arrives in about a week and when about one-fourth grown. Here it feeds upon the seeds and flesh around the core until it has attained its growth. When pene- trating to the core, the larva keeps its burrow clear by pushing to the outside the portions of excrement, and this brown frass in the blossom end or elsewhere is the usual indication of infestation by this species. (See PI. LIII, fig. 1.) Larvae of the second brood, unfortunately, do not enter the fruit at the calyx end to éhe extent that is true for those of the first genera- tion, which renders them more difficult to combat. In fact, injury by the larvae of this generation is best avoided by thorough work against those of the first, destroying them as much as possible. Statistics by Simpson indicate that only 26 to 28 per cent of second-brood larvae enter the calyx end, as against 81 to 83 per cent of the first brood. The time spent in the fruit varies considerably and is variously stated at from ten to thirty days, with an average of about twenty days. Observations on this point with second-brood larvae by Messrs. Melander and Jenne in Washington show a range of eighteen to thirty days, the average being about twenty-three days. Prepara- tory to leaving the fruit the apple worm bores a hole to the exterior, rarely along the entrance burrow, but in another direction, keeping the orifice closed, however, with a silken cap or plugging the hole with excrement until ready to desert the fruit. The time of leaving the fruit is, during warm weather, mostly at night, but later in the season, when nights are cool, this occurs more often during the day. Once outside of the fruit, when this is on the tree, the larvae mostly crawl from the fruits to the twigs and thence down to the larger branches or trunk, and, finding a suitable crack, hole, or bark scale, begin at once to spin a cocoon. On smooth-barked trees many go to the ground, penetrating the cracks at the base of the tree or going under rubbish or clods. Most larvae desert the apples before these drop, but when they fall with the fruit the caterpillars simply crawl to some near-by protection and there spin their cocoons. The larvae will pupate in large numbers under objects leaning against the tree or in bands of hay, burlap, or other material tied around the limbs and trunks. Banding to thus trap the larvae has long been practiced 440 YEARBOOK OF THE DEPAKTMEÑT OF AGEICtTLTURE. in the control of the codling moth, and before the accidental discovery in 1878 of the value of arsenical sprays this method, together with the gathering of fallen fruits, was mostly relied upon to keep the pest in subjection. THE COCOON AND PUPA. All through its life the larva spins from a tube on the lower lip a silken thread useful in various ways and especially for making, when full grown, a protecting covering or cocoon within which to change to the pupal stage. Having found a suitable place it be- gins to weave about itself, strand by strand, a covering of whitish silk, elongate or capsular in shape, but conforming to the cavity where situated. About a day is occupied in constructing the cocoon, within which, if late in the season or in regions where there is but one an- nual generation, the larva will remain in hibernation until the fol- lowing spring, or, in regions where climatic conditions favor another generation, the body contracts in length, its segments become more distinct, and in three or four days the larval skin is shed and the pupal stage entered. The pupa is about half an inch long, varying according to age from a yellow to brown color, becoming of a bronze hue shortly before the moth is to emerge. The abdominal segments above, except the first, are armed each with two rows of backward-pointed, short, stout spines, there being but one row, however, on the two caudal segments. These spines are used by the pupa in pushing itself partly out of the cocoon to permit the escape of the moth. The wing and leg sheaths reach about the middle of the fourth abdominal segment, the antennal sheaths being slightly shorter. The cremaster is com- posed of a sparse circle of slender hairs, slightly curved at the tip, which assist in holding the pupa in place in the cocoon. (See PI. LII, fig. 3.) The time spent in the pupal stage is variable. , This period in the spring, with over-wintering larvae, according to Messrs. Melander and Jenne, varied from twenty-one to thirty-six days, with an aver- age of about twenty-eight days, while in 1905, owing to a cooler spring, the range was twenty-nine to fifty-one days, with an aver- age of about forty-three days. The time spent in the cocoon during summer is shorter; thus, according to the authorities mentioned above, the average during June and July is about twenty-two days, and dur- ing August and later, thirty-four days. Records by Professor Gil- lette in 1900 give a maximum of twenty-nine days, a minimum of twelve days, and an average of twenty days. Records by Simpson in 1902 give an average minimum of fourteen days, and in 1902 the period varied from eleven to forty-nine days, the average being twenty-two days. In general, for the country as a whole, the time spent by the larva and pupa in the cocoon will average not far from Yearbook U. S. Dept. of Agriculture, 1907. PLATE LII.
THE CODLING MOTH AND ITS CONTROL. [Fig 1 —Young npplos, sliowiiip, on left, calyx loties open, und in right condition for first pprny- in¿- onriglit ciilvx lobes dosed, and almost, if notqiiite. t FIG. 1.—YOUNG APPLES, SHOWING FRASS AT CALYX END AND WHERE APPLES ARE IN CONTACT, THE WORK OF LARV/E OF FIRST GENERATION OF THE CODLING MOTH. SOMEWHAT REDUCED. (ORIGINAL.) FIG. 2.—MATURE APPLE CUT OPEN, SHOWING APPLE WORM OF SECOND GENERATION AND ITS WORK. SOMEWHAT REDUCED. (ORIGINAL. ) WORK OF THE CODLING MOTH OR APPLE WORM. THE CODLIKÖ MOTH OR APPLE WOEMw 441 twenty days. These data, especially the minimum periods of life in the cocoon, are important in connection with the use of bands, to be mentioned under the head of remedies, as indicating how frequently these should be examined to avoid the development and escape of the moths. When the pupa is matured it works half way out from the cocoon, the skin splits down the back, and the adult quickly es- capes by pushing away the head end of the pupal skin. The moth, at first wet and with soft integument and crumpled wings, soop dries, the wings expand, and the insect disappears in the foliage, the whole process requiring not more than fifteen or twenty minutes. In a few days the sexes mate and the females begin the deposition of eggs. THE ADULT OB MOTH, The adult codling moth is variable in size, the wing expanse, how- ever, never exceeding three-quarters of an inch. The forewings have a brownish-gray silky appearance, being crossed with dark and white lines, and near the tip is a brownish-colored spot or ocellus in which are two irregular lines of a metallic coppery oip golden color. The hind wings above are grayish-brown, darker toward the margin, which bears a delicate fringe, at base of which is a narrow dark line. The color of the moth is such that when at rest with folded wings on the grayish bark of an apple tree it so harmonizes with its surround- ings that it is not readily distinguished, and this stage is not Ordi- narily seen by orchardists. (See PI. LII, fig. 4.) The males and females are readily distinguished, the male exhibit- ing on the lower surface of tlie front wing an elongate blackish spot, and this sex also has penciled, long, black hairs on the upper surf ace of the hind wings. In the orchards the moths are said to rest com- monly on the upper surfaces of leaves or on the trunks of the trees. When disturbed their flight is rapid and erratic, and can hot long be followed. The food is possibly neótar from flowers, juice of ripe apples, etc., as they feed in confinement on sweetish juices and also on water. The length of life of the moth will depend much on the suiround- ing conditions. Records vary from one to fifteen or seventeen days; the average life of 47 moths in August, 1902, without water or food, as stated by Simpson, was four days. Unquestionably with food they live much longer, and moths appearing in late fall may survive several weeks, though they never hibernate, so far as observed. LENGTH OF LIFE. The average time for the respective stages, as stated in the fore- going, is, for the egg, eleven days; the larva, twenty days; the pupa, twenty days, and with five days intervening from the emergence of the moth until egg-laying begins, there is a total of fifty-six days. 442 YEABBÖO^K OF THE DEPAKTMENT OF AGBIGUIiTURE. Eecords for the summer brood by Professor Gillette in Colorado give, for the egg, seven days ; the larva, nineteen days ; the pupa, eighteen days; and with five days from emergence of moth to middle of egg laying, there is a total of forty-nine days. In general, it may be said that the life cycle requires some seven to eight weeks. NUMBER OF GENERATIONS. Despite the large amount of work which has been done on this species, there is yet need of information regarding the number of generations each year in different parts of the United States, and on the proportion of first-generation larvae which transform for the second generation in regions where this latter is not a full one. As is at once apparent, knowledge on this subject is of much practical importance as bearing on the treatment to be employed. Where there is a large partial or full second generation the injury is notably greater. In general, however, it may be said that through- out the New England States and southward at least to the lati- tude of Washington there is one full generation each year and a partial second. In the northernmost part of the territory indicated, as in Maine and New York, the second generation of larvae will be light, varying in extent from season to season, while in the southern portion it becomes quite large and during favorable years it is prac- tically a full one. Two full generations have been reported by Pettit for Michigan, and, according to Messrs. Green and Houser, it is thought that this condition will be found to obtain in Ohio. Ade- quate data are not at hand for other Central States of about this latitude. A full second generation of larvae was determined by Mr. Dudley Moulton of this Bureau for Nebraska City, Nebr., in 1906. Eiley records two generations for Missouri, and the same condition has been shown for Iowa by Walton and also indicated by Grillette. In the latitude of Chicago, as stated by Le Baron, a great majority of first-brood larvae transform to moths during the last two weeks in July. In general, for these Middle States it would appear that the insect is two-brooded or that the second is of sufficient extent to war- rant its being so considered for practical purposes. In States of the latitude of Virginia, Kentucky, Kansas, and Colorado two full gen- erations may be expected each year. Careful studies have shown that there are two full generations in States of the far West, as Washington, Oregon, Idaho, Montana, Utah, California, and Colo- rado. Band records in New Mexico, by Prof. Fabian Garcia, seem to show that the codling moth is in that Territory three-brooded, and at Siloam Springs, Ark., during 1907, Mr. E. L. Jenne, of this Bureau, obtained practically a full third brood in breeding cages, though it does not follow that this condition would obtain in orchards. THE CODLING MOTH OB APPLE WORM. 448 NATURAL ENEMIES. While the codling moth in its several stages is subject to attack from numerous natural enemies, the number is smaller than for many other lepidopterous insects leading a more exposed life. The eggs are parasitized by a very minute four-winged fly, Trichogmmma pretiosa Riley, which deposits her eggs in those of the codling moth, three or four grubs or larvae finding sufficient food for their devel- opment to the adult condition in a single codling-moth egg. The larva, although living most of its life protected within the apple, is nevertheless parasitized by several species of hymenopterous insects, as Pimpla annulipes BruUe, Maerocentrus delicatus Cress., Goniozus sp., Bethylus sp., and a tachinid fly, Hypostena variabilis Coq. Numerous parasites attack the codling moth in Europe,« among which are Campoplex pomorum Eatz., Pristomerus vulnerator Panz., Phygadeuon hrevis Eiley, and Cdlliephialtes messor Grav. The last of these has been recently introduced into California by the horticultural commission of that State to prey upon the codling moth. Numerous predaceous insects in their larval stage have been recorded as preying upon the codling moth, though some are possibly merely scavengers, feeding upon the insect after death. Among these SLve OhauUognathus pennsylvanicus DeG., ¿7. marginatus Fab., Télephorus hüineatus Say, Tenébrioides corticallis Mels., T, laticoUis Horn, Trogoderma taradle Mels., Pterostichus califorrdcus Dej., and Galathus sp. A raphidid (Rhaphidia s]^.) is an enemy of the codling moth in the far West, searching out and destroying the larvse under bands. In Utah, a wasp (Ammophila) has been found stocking its burrows with cod- ling-moth larvse, and in California Sphedus nevadensis Cress, has been seen pulling the larvse from their burrows. Birds constitute by far the most important natural enemies of the codling moth, especially woodpeckers, and it is highly probable that most of those frequenting orchards include the codling moth in their diet. So diligently do the woodpeckers search over the trees for the hibernating larvse that by spring these have been largely destroyed in the more exposed situations. The benefit derived from the work of these birds warrants their protection and encouragement to the fullest extent possible. The species of birds definitely recorded as feeding on the codling moth are as follows : Downy woodpecker (Z>7^ö- . bates puhescens)^ Texan woodpecker {Dryohates s. lairdi)^ red- headed woodpecker {Melanerpes erythrocephalus) ^ ved-sh^ited flicker (Colaptes cafer)^ kingbird {Tyrannus tyrannus)^ magpie {Pica pica hudsonia)^ crow {Corvus hrachyrhynchos) ^ crow blackbird (Quis- calus quiscula)^ cardinal {Gardinalis cardinalis)^ black-headed gros- «See J. T. Schreiner, in Zeitschrift für VS^issenschaftUche Insektenbiologie, Heft VII, December 9, 1907. 444 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. beak {Zamelodia melanocephala)^ warbling vireo {Vireô gilnus)^ chickadee {Parus atricapillus)^ hnsh-tit {Psaltriparus minimus) ^ snid bluebird {Sialia sialis). There are indefinite records of the follow- ing birds feeding on the codling moth: Sparrows, swallows, jays, wrens, creepers, and nuthatches. METHODS OF CONTROL. The codling moth is best controlled by the use of arsenical insecti- cides sprayed on the trees. The application of the arsenical in States eastward of about the Rocky Mountains is usually made with Bor- deaux mixture,« effecting a combination treatment for the codling moth and fungous diseases of the fruit and foliage of the apple as well. The arsenical also controls canker-worms, the tent caterpillar, and a number of other bud and leaf feeding insects, and affords much protection against the plum and apple curculios. In regions where fungicides are unnecessary the arsenical is ap- plied in water, preferably with the addition of a small quantity of freshly slaked lime (1 to 2 pounds for each 50 gallons of water) to prevent as much as possible any caustic action of the poison on the foliage; with arsenicals such as Paris green the lime also serves to show how thoroughly the spraying is being done. USE OF ARSENICALS. Paris green, arsenate of lead, arsenite of lime, and Scheele's green are the principal poisons used against the codling moth and in about the order named. PAEIS GREEN. Paris green is used on apple at the rate of about 1 pound to 150 gallons of Bordeaux mixture or water. One pound to 100 gallons will frequently prove too strong, causing serious burning of the foliage. The dry poison is first worked into a paste with water to insure its better distribution in the liquid. ARSENATE OF LEAD. Arsenate of lead is deservedly coming into very general use for the codling moth and bids fair largely to supplant other poisons. Its advantages are (1) that it sticks well to foliage and to fruit, not being readily washed off by rains; (2) the complete absence of free arsenic in properly made preparations, so that it may be used quite strong without danger of injury, and (3) its white color, by which it is possible to tell how thoroughly spraying is being done. It is used at the rate of 4 to 6 pounds to each 100 gallons of Bordeaux mixture or water. As found on the market it usually comes in the form of a putty-like paste which must be worked free in a little water « See Farmers' BuUetin 283, U. S. Dept. Agrie, " Spraying for Apple Dis- eases and the Codling Moth in the Ozarks," p. 34 (1907). béfété addition to thé sprsj tank. There are now numerous brands oï'arsenâté of lead on the market and the prospective user should be careful to buy an efficient and safe kind. A satisfactory kind should be practically free from salt (NaCl) and by-products, should contain no free arsenic, and should have as much as 50 per cent actual lursenate of lead. This arsenical may be prepared at home from the ingredients used in its commercial manufacture, as arsenate of soda and acetate of lead. Except where used on a considerable scale it will, however, be ad- visable to employ a reliable commercial product. In purchasing the ingredients for the homemade ^rsenate of lead the dealer or manu- facturer should be required to furnish a guaranteed analysis of the ingredients and to indicate the exact amounts of each, by weight, which should be employed to produce complete combination. ABSENITE OF LIME. Arsenite of lime is the cheapest of the ars^cal poisons and has proved to be satisfactory on. apples when properly prepared. The Kedzie formula is as follows: White arsenide, 1 pound; sal soda crys- tels, 4pounds; wafer^ 1 gallon. All of the mgredi^nts are boiled to- gether in an iron vessel for fifteen minutes or until the arsenic dis- solves, leaving only a small quantity of muddy sediment. Any water lost by evaporation should be replaced. This constitutes a stock solu- tion, and 1 piut is approximately equal in arsenic (íonteíít to 4 ôiïÎQces of Paris green. Wheá desired for use 1 or IJ pints is added to each 50 gallons of the Bordeaux mixture or water. When vised in Water there must be added the milk of lime made from slaking 3 or 4 pounds of good ôtone Ume wtich is necessary to produce the arsenite of lime. A still cheaper method (Taft'sfoîteula) is to boil together foi forty minutes 1 pound of white arsenic and 2 pounds orf lime in 2 gallons of water, which is sufficient for 300 to 400 plions of spray liquid. There is always danger of incomplete union of the arseni« and lime and injury to the foliage may result ; 3 to 4 pounds of fr^h- siaked lime should always be added to the spray tank before usiiig. . , ■ - ' ■ ■ -, . • i SCHEELE'S OREEN. Scheele's green is very similar to Paris green, but cheaper, as it does not contain any acetic acid. It is a finer powder, remaining in suspension longer,, and is used in the same way and at the same strength recommended for Paris green. SPBAYING APPARATUS. , The orchardist can hot expect best results in fighting the codling moth and other insects and diseases of the apple unless he be pro- vided with efficient spraying apparatus. Principally three types of spray pumps are used in ordiards, namely, the barrel piuup, the 4-^6 YïlABBOOK GF THE ^EP^JITMENT DP ÀGSICTJLTtJBE^ hand-power tank outfit, and the gasoline sprayer. In the first the pump, according-to its design, is fitted to the end or side of^a 50-gallon barrel, which is placed in a wagon, or (less usually) car- ried on wheels or on a sled. The pump should be fitted with two 20 or 25 foot leads of hose, bamboo extension rods, and double nozzles, and if of proper construction there should be no trouble in obtaining suitable pressure for effective work. Barrel pumps are used mostly in small orchards.' Tank outfits are desirable for larger orchards, and consist of half- round tanks holding from 100 to 300 gallons, flat on top and fitted to the wagon in place of the wagon bed. Hogshead tanks of 100 to 200 gallons each placed upon one end of the wagon are also used. The barrel type of pump may be employed with these tanks, but it is preferable to use the large tank pumps made for the purpose, with double cylinders and with suction hose. Such a pump (see PL LIV, fig. 2), if properly run, gives excellent pressure with two 20 or 25 foot leads of hose, and with double or even triple nozzles. When the orchard interest warrants, however, a gasoline or other power outfit should be used which will niaintain a pressure of 125 to 150 pounds, with several leads of hose and double, triple, or quad- ruple nozzles. A high pressure results in a fine, mist-like spray, pene- trating to all parts of the tree, insuring a thorough and even distribution of the poison. (See PI. LIV, fig. 1.) A common defect in many outfits is that the hose is not of sufficient length ; it should be long enough to admit of spraying on all sides of a tree before leaving it. Inadequate provision for agitating^'the liquid in the tank is another common defect. This results in uneven distribution of the poison. Extension rods 10 to 16 feet in length are indispensable, and a derrick or platform should be provided on the wagon on which one or more men may stand to spray the higher parts of the tree while men on the ground are spraying as high' as may be reached. One of the most important features of the spray- ing outfit is the nozzle. The Vermorel type, with medium to small apertures, is best. The orchardist should not make the mistake of fitting an otherwise good outfit with poor nozzles. SCHEDULE or APPIilCATIONS. FIRST APPLICATION.—^This should be made as soon as the petals or blossoms have fallen, and has for its object the placing in the calyx cavity of each little apple a dose of poison to be later eaten by the larva as it seeks to enter the f tót. This is much the most im- portant of all treatments. At this time the young apples are mostly upright on the stems, and much more effective work may be done by spraying from above downward. Between the extension rod and the nozzle^ for this spraying, an elbow fitting should be used, or the cham? Yearbook U. S. Dcpt. of Agriculture, 1907. PLATE LIV.