r United States PepnriiikMii uf \unViilture, nir vi-i'i i i BEE tin i ( v i iiti'ii i vi i UalticoxoMHi ami * i< una I 'nb. i /;/ Chargi Bj \. I.. Qi u\i I Deciduous Fruit Insert Investigation*. The conspicuous, unsightly nests or tents of this insect (fig. -J) are familiar objects in the spring in trees along roadways, streams, fences in neglected orchards, and elsewhere. The gregarious cat- erpillars construct the tents for their protection, and these, at lir-i small, are gradually enlarged as the larvae grow, often h or more in height and diameter, the size varying with the nu sin 1 i . of individuals in the colony. The caterpillars feed upon the foli >f the trees, stripping the leaves from the limbs adjacent to the nest, and if the era) colonies in a ti e, is frequently the during periods of abundant e, >liage may be quite d Leaving the branches as bare as in midwinter. us DISTRIBUTION AND FOOD PLANTS. The tent caterpillar is a native American species occurring quite generally in the United State- from Canada south to Florida and westward about to the Rocky .Mountains. From the Rockies to the Sierras, according to Dyar, the species is replaced by Malacosoma fragilis Stretch, which range- from Canada to Mexico, and this lat- ter form in the Pacific Northwest is replaced by Malacosoma plu- vialis Dyar. The tent caterpillar has been a troublesome pest from the earliest limes. As stated by Fitch, its injuries in Massachusetts in the years L646 and 1649 led the early settlers to term these "caterpillar years." At rather long and irregular intervals the caterpillars have been excessively abundant in different parts of their range, but more particularly in the New England States. This species was among the first to receive attention by the early American entomologi-t-. and the principal feature- in it- life and habits have been known for many years. Throughout its extended distribution the insect is likely to be abundant each year in one or more localities and often over a considerable territory. Scattered nests are to be found usu- ally during any spring, though during some seasons these are but little in evidence. The favorite food of the tent caterpillar is the wild cherry, and this is probably its native food plant. Next to the wild cherry the apple is apparently preferred. In the absence of its favorite food, or under special condition-, it attacks many other plants, as plum, peach, thorn, pear. rose, and other members of this group; also beech, witch-hazel, elm. maple, various species of willows, oaks, and poplars, etc. During period- of unusual abundance trees are more or less completely defoliated, and at a time when they most need the leaves for their growth or for the development of the fruit, and they are materially weakened, though rarely killed. DESCRIPTION AND LIFE HISTORY. The egg. — Eggs are deposited in masses or belts encircling the -mailer twigs, as shown in fig. -J. and at a, fig. 1. Different ^gg masses may vary from one-half to three-fourths of an inch in length and contain from 150 to 250 eggs. The average number of eggs in several egg masses counted by Prof. V. II. Lowe on peach and apple was tbout 223 each. Each egg belt i- deposited by an individual female ind ordinarily represents the entire number which she will deposit. Eggs are placed on end. cemented closely together, the whole oval- shaped mass being finally covered with a layer of light-brown frothy glue, which soon becomes tough, brittle, and glistening. [Cir. 98] .,,. deposited bj the rnotha bj earl) midsummer, ... earhei in the South, the embryonic lar > thai bj fall the} are Drac ticall3f full grown, although remaining within the egg until the n , •■ -Apple-tree tenl MterpUtare i " " ..„"!!... twig at left. ne - haM "^ il.) following spring. With the comii warm spell the larva escape by gnawing through their egg shells, often before there is foliage out for food, and under these circumstances they may feed upon the glutinous covering of the egg mass. The larva. — In the presence of food the larva" begin the formation of their nesl in about two days from hatching, usually selecting the crotch formed by two limits and ordinarily one that is not far from the egg mass. The caterpillars are sociable, those from one egg mass inhabiting one nest and feeding together upon the adjacent leaves. If two egg masses happen to be deposited close together, as on the same or adjacent twigs, the resulting caterpillars may mute in one nest. Wherever they go each larva spins a thread of silk, the young individuals hanging suspended from a silken thread when they drop, as do the cankerworms and many other larvae. The nests, at lirst small and affording but little shelter, are gradually enlarged as the caterpillars grow and soon furnish ample protection. Upon (dose examination the nests of this species will he found to he made up of layers of silk, with room for the larvae between the layer-. According to Fitch these layers are the resull of the caterpillars" habit of lying on the outside of the nest during bright weather, the few restless individuals crawling hack and forth over the resting mass, spinning silk as they go, soon forming a new layer. During rainy and cloudy weather the larvae remain mostly within the nest, hut when the weather is favorable they feed at regular intervals; according to Fitch, in the morning, in the afternoon, and again -dur- ing the night. Upon becoming nearly full grown the larvae wander singly away from the nest, feeding upon such plant- as come to hand. This wandering habit preparatory to pupation results in the scatter- ing of the pupa 1 and greatly increase- the chances of their escape from destruction from their numerous natural enemies. When full grown the caterpillars are about 2 inches long, cylin- drical, deep black in color, with a white stripe along the back and lateral markings, as shown in fig. 1, b. On each side i- a row of oval pale-blue spots, one on the middle of each segment, and on the ante- rior side of each is a broader, deep velvety black spot. The body is sparsely clothed with fine soft yellowish hair- of varying length, thickest perhaps toward the anterior end. where they project forward over the black-colored head. In about six weeks from hatching the larvae become full grown ami wander away from the nest, as stated, in search of suitable places for pupation. The cocoon. — The larva 1 select for pupation any convenient, more or less secluded place, as under loose bark, in grass or brush under trees, along fence-, etc. If close to outbuildings the larvae often make their cocoons in the angles' along the sides, in window casings, etc. The cocoon, shown at <1. fig. 1. i- oval in shape, about 1 inch lone-, md composed exteriorly of coarse, loose, whitish threads of silk [Cir. !>s] ncYmg the tougher parchment-like lining. The silk of the i- intermixed n itli n yellow powdi tancc which readily comes off when disturbed. C i are made more or less singly, though in suitable shelter near the i eral may be found spun together, the larva taking nd vantage of the same • ""»ii- are frequentl} found within the nest, though these will usually l'i'"' •• i" be parasitized. 1,1 Within the cocoon the larva changes to a short, oval, brownish pupa, as shown at c, fig. I. This stage lasts about three ks, the time varying somew hat ; then the moth app< Both sexes of the tent caterpillar moth are shown in ''-• '• li "' female to the left. I' .lull reddish brown, stout- bodied moths, with a wing expanse in the females of about L.5 to 2 ■nches, and in the males of from L.2 to L.3 inches. Obliquely across the brewings of each sex are two nearly parallel whitish lines, as shown n. the illustration. Soon after emergence the sexes mate, and lv deposited on limbs and i •■ I re b Deration hyear, the insects existing in the egg stage throughout the remain- m « s mer Mti.l fall and through the winter, the voung larva? com- ing Prom the eggs in early spring and forming their nests, or tent stated. NATURAl ENEMIES. This species is subject to attack by numerous parasitic and daceous enemies, which undoubtedly exert an important influence in "'"- »« reduced. Very minute, four-winged flies of the order Hymenoptera deposit their eggs within those of the tent caterpillar moth, the resulting larvae or grubs finding sufficient food for their growth and development to parent flies. Four egg parasit been recorded for this species, namely, . ipa u\\ry. Pteromalvs sp., Platygaster sp., and Ah ,,,, Ajshm.' the latter record, however, being undoubtedly incorrect, since this species is parasitic upon scale insects. Larva? and pupae furnish f I for a large number of parasites and hyperparasites. Thus W. V. Fiske records a total of some 2J species of insects which directly or indirectly f I upon the tent caterpillar. Primary parasites which have been recorded from the larva and pupa are: Pimpla ■ , • - . /-. '"•i S P. Cress., /'. n Brulle, ApanU s var - Riley, A. kshm., I. Itivum Say, .! nw clvnocampa Weed, AnomaLi Prov., .1. ant ' Say, Spilot >■>;, . s ( Jn Cress., B V.shm., Diglochh omn ' Walk., •Tech. Bui. So. 6. \. li. ■ s< ,.. ,,. ■_. , ■ [Clt Theronia melanocephala Brulle (?), and the dipteron Frontina in nchii \\"\\\. Among predaceous insects are several species of ground beetles which arc said to feed upon the larvae, among them Calosoma scruta- tor Fab. Among the Hemiptera Mr. A. II. Kirkland has observed several species of Podisus attacking the larvae {Podisus placidus DhL, /'. modestus Dall., and P. serieventris Uhl.) and the rudiviid Di- plodus luridus Stal. Also, according to Professor Bruner, Podisus spinosus Dall. and Perillus claudus Say are enemies of the caterpil- lar-. While most birds, as a rule, do not feed on hairy larva 1 , such a> the tent caterpillar, yet several species are known to include this insect in their diet, as the black-billed and yellow-billed cuckoos, the bluejay, and. according to Mr. E. II. Forbush, the crow, chickadee. Fig. '■',. — Pimpla conguisitor, an important parasite 'of the tent caterpillar: «, Larva, enlarged ; b, head of same, still more enlarged : <■. pupa : \ le their favorite food supply. Collecting the eggs. During the dormant period of trees, when the leaves are off, the egg mas e are fairlj con picuous, and with a lMl1 '' Practice may be readilj found; it is then thai they should be mi ofl Bnd burned. In. infi ted with larva? during the earl) pari ".' ''"' . vr;,r - " r thos e '" the inn liate vicinity, are perhaps more likely to be chosen l.\ the parent moth for the deposition of her eg and such trees at least should be searched if it is not practicable to e f tend the u, "' k to th -chard as a whole. This work may som bined with pruning to good advantage, and a lookoul should be kept not < > 1 1 1 \ for the eggs of this msec! but for the eggs and cocoons of "(her injurious species which pass the winter on i he t rees. I BOl riw PHI • \ i i BP1 I i uts, N iglecl to search out the masses during the \n inter \\ ill resull "i the appearance of the larvse about the time the trees are putting forth foliage. The nests, at 6rs1 small, are soon so increased in size as to attract attention. I f the cater pillars are destroyed as soon as the small nests are detected, this will prevent further defoliation of th.' trees, and the rule ~ln.nl. 1 be adopted to destroy them promptly as soon as discovered. In this work nil,.., oi two practices may be resorted to. namely, destruction bv hand or with a torch. When in convenient reach the nests may be tun, oul with a brush mth g loved ll: "" 1 or otherwise, and the larvae crushed on th, ground, care being taken to destroy any caterpillars which may have remained on the tree. TIu ' use " { ;l to"* to burn out th,' nests will often I... found anient, especially when these occur in th, higher part- of An asbestos torch, such a. advertised by s Ismen, will I,' "f on,, may be made simply by tying rags to the end of a pole Tip. asbestos or rags are saturated with kerosene and lighted ami the caterpillars as far a- possible cremated. Some caterpillars, hov are likely to escape, falling from the nesl upon the application , torch. In using the torch great care is necessary that no impoi ■ h, h, the UNIVERSITY OF FLORIDA s 3 1262 09216 5454 injury be done the tree: it should not be used in burning out nests except in the smaller branches and twigs, the killing of which would be of no special importance. Nests in the larger limbs should be .lot roved by hand, as the use of the torch may kill the bark, resulting in permanent injury. Spraying with arsenicals.— TevA caterpillars arc readily destroyed by arsenicals sprayed on foliage of trees infested by them.' Dr. li Fernald's careful experiments and those of Professor Lowe in deter- mining the amount of poison necessary to kill the caterpillars show that the latter are very sensitive and are killed in from two to three day- by the use of Paris green at the rate of 1 pound to 300 or 100 gallons of water. Orchards or trees sprayed with arsenicals in the spring for the codling moth, cahkerworms, or similar insects will be kept practi- cally free from tent caterpillars, and this species rarely requires at- tention at the han.K of the up-to-date commercial fruit grower. It will he troublesome in the scattered trees around the home or in the small orchard which is not regularly sprayed. On such trees the nests will likely he in evidence every spring, and during occasional years the caterpillars may he excessively abundant, completely de- foliating the trees. Even in the small home orchard of a dozen or more tree- it will he found highly profitable to adopt a system of spraying which will control not only tent caterpillars but such serious pests as the codling moth, cankerworms, various bud and leaf feeding insects, and will greatly reduce injury from the curculio. Any of the arsenical insecticide- may he used, a- Paris green, Scheele's green, arsenate of lead. etc. The former two are used at the rate of 1 pound to 150 or 200 gallons of water, and the latter at the rate of -2 pounds to 50 gallons of water, the milk of lime from an equal amount b\ weight of stone lime, as poison used, being added to neutralize any caustic effect of the arsenical on the foliage. Pref- erably, however, the poisons should !»e used in Bordeaux mixture, thus effecting a combination treatment for insect- ami fungous dis- eases. On -tone fruit-, such a- cherry, peach, and plum, arsenicals are likely to cause injury to foliage and must be used with caution if at all. On such tree- the arsenate of lead i- preferable, a- it i- 1 injurious to foliage, and on all tret- -ticks much better. In spraying for the tent caterpillar only, application- should be made while the caterpillars are yet -mall, a- these succumb more quickly to poiso than when more nearly full grown, and prompt treatment stops fur- ther defoliation of the tree-. Approved : James Wilson, Seen tary of Agricultx Washington, D. ('.. December ■/. /."< OS j o