Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. ‘UNITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 805 Contribution from the Bureau of Entomology L. O. HOWARD, Chief Washington, D. C. _ PROFESSIONAL PAPER December 15, 1919 TWO LEAFHOPPERS INJ URIOUS TO APPLE N oe STOCK By A. J. ACKERMAN, Scientific Assistant Deciduous Fruit Insect Investigations ‘CONTENTS Page : Introduction . . .....- - 1 | The Rose Leafhopper ... . The Apple Leafhopper f 2 History ....«=« >» s History ... . 2 Synonymy . . » « » * Distribution .. 2 Origin and Distribution . . Food Plants .. . 3 Food Plants ... . - Character of Injury ....e.-. 4 Character of Injury. ... Extent of Injury and Influencing Description of Stages . .. PACLOLS ches ou a er athe ae een RS Life History and Habits. . Description of Stages. . .... =5 Summary of Seasonal History Allied Species ... 2: ose » 6 Natural Enemies. . . . . « Life History and Habits. . ... 7 | Remedial Measures. .... » Summary of Seasonal History . . 19'| Summary ..... «222» Natural Enemies. . ... +» . . 20! Literature Cited . ..... ‘WASHINGTON GOVERNMENT PRINTING OFFICE 1919 UNITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 805 (A Contribution from the Bureau of Entomology L. O. HOWARD, Chief Washington, D. C. PROFESSIONAL PAPER December 15, 1919 TWO LEAFHOPPERS INJURIOUS TO APPLE NURSERY STOCK. By A. J. ACKERMAN, Scientific Assistant, Deciduous Fruit Insect Investigations. CONTENTS. Page. | Page. MMETOGUCHON A Me eek eee ects ale ae i) Dire: rose leafhoppensseee- els ous el Soe 20 Mheappleleafhopperss. 2 sacha. oe Moe ee 2 TTS COTY Malpas cia vafeia ae leialeinsictewlo sient 20 ASCOT Yeo Wa sess sarseie as etre lainie salcie te 2 SYMON YAN A eee meer acta se leincens eee eae 21 Distrib Wtloney eee eee seeiteee ae sen 2 Origin/and distributions 22-222 ess... 21 ROOGNDLATIES pit en ease ei cisiale a iteteie lao 3 Hood? plants wrens slotis siecle joe ce eee eee 21 Character lim Ub yaa see ee sweet slele 4 Characterohinyunyeeeeces seen eseee aces 22 Extent of injury and influencing factors 5 Description of/stagesses sence see eee 22 Desceriptionjof stages. se. 6 22sec. a. 5 ifemhistonysandshabitsessseseseceeseses- 23 FAITICAISECTESS Meu Bye Lt ea ani wey hee 6 Summary of seasonal history...-.......- 28 Life history and habits. .../.-./.....2-- 7 Naturalenemiessiseyseses. 5 ese. ce ae 28 Summary of seasonal history...........- LOG MREmMedialym CasuTe sees ecm: meen arse vyel uae 29 Natural enemiesceenoee scuececsouue aoe. + PAU Weg 00 COKEN AArpies 4 Ae aR ape anal asia Rt ae ph CY 33 TeiperaturecibedMscehe.-- jase sce weecepmede sects 34 INTRODUCTION. Serious injury to apple nursery stock due to the attack of leaf- hoppers attracted the writer’s attention while engaged in the investi- gation of nursery fruit insects at West Chester, Pa. An examina- tion of the injury showed the presence of two species of leafhoppers, the common apple leafhopper! and the rose leafhopper.2. Further study proved that each species produced a distinct type of injury, that caused by the apple leafhopper being by far the more serious. The conflicting nature of the entomological literature regarding the char- acter of injury caused by these two species and their habits led the writer, under the direction of Dr. A. L. Quaintance, of the Bureau of Entomology, to undertake a study of their individual life histories and the means for their control. 1 Empoasca mali (Le Baron); order Hemiptera, suborder Homoptera, family Cicadellidae. 3 EHmpoa rosae (Linn.); order Hemiptera, suborder Homoptera, family Cicadellidae. 132816°—19——1 2 BULLETIN 805, U. S. DEPARTMENT OF AGRICULTURE. The destructiveness, habits, food plants, and life history of each species are treated separately herein. A detailed account of the ex- perimental work carried out for the control of these two species to- gether with the most efficient remedy is included. The data on biology and control were obtained at West Chester, Pa., during the seasons of 1915 and 1916, supplemented by field ob- servations at several points in southeastern Pennsylvania, and western Maryland. THE APPLE LEAFHOPPER, Empoasca mali (Le Baron). HISTORY. This species was originally described by Le Baron (1) in 18531 under the name Tettigonia mali, and it was recorded by him as in- jurious to fruit trees in Illinois. In 1862 the genus Empoasca was erected by Walsh (2) with a description of three new species, but no mention was made of mali. Carlos Berg (3, p. 273), in 1879, described a leafhopper from Argentina as Typhlocyba phytophila, and this name later was considered by Gillette to be a synonym of Empoasca mali. In 1883 Forbes (4) sent specimens of a green apple leafhopper to Uhler who determined them as belonging to the genus Empoa; subsequently these insects were described by Forbes (5) as a new species, Empoa albopicta. Woodworth (6) transferred HEmpoa albopicta Forbes to the genus Empoasca in 1889 and called it Empoasca albopicta. The first reference to this species under its correct name, Empoasca mali, was made by Gillette (7) in 1890. Osborn (8) and later Gibson (17) mentioned it as injurious to potatoes, and Gillette (9), in 1898, gave the food plants and distribution. Frequent references to this insect have been made in American entomological literature under the name of ‘‘the apple leafhopper”’ and ‘‘the currant leafhopper,’ by Britton (12), Brues (13), and Gar- man (16) among others. It has been often referred to as the most injurious leafhopper, both to apple and to various field crops. Wash- burn (15), in 1908, was the first writer to treat of this insect at any length. He published a record of the seasonal history, food plants, injury, and control of the apple leafhopper as a nursery pest in Min- nesota. In 1910 R. L. Webster (18) made a detailed study of the life history and control of this insect on apple nursery stock in Jowa. In 1915 Webster (20) published an account of Empoasca mali, treating it as a pest of potatoes. DISTRIBUTION. There are no records showing that the apple leafhopper occurs in Europe. In America, outside of the United States, it has been re- ported from Okanagan, British Columbia, from Nova Scotia, several 1 Figures in parentheses refer to ‘‘ Literature cited,” p. 34. TWO LEAFHOPPERS INJURIOUS TO APPLE NURSERY STOCK. 3 points in the Province 01 Ontario, from Mexico, Porto Rico, and Cor- rientes, Argentina. In the United States this species is widely dis- seminated, doubtless due to the variety and abundance of its host plants. From speci- mens in the collection of the United States National Museum, and from the collec- tion, correspondence, and notes of the Bu- reau of Entomology, 1 ubeppeamasta, lea kieey Fic. 1 uae he ee ye ent in almost every IG. -—Vi1stripution oO e® ae ealhopper ™m State in the Union. cn ey (See fig. 1.) Itis found in greatest abundance throughout the east- ern humid area of the Upper Austral Zone. poasca mali) in FOOD PLANTS. The food plants of Empoasca mali (Le B.) are very numerous and varied. In nurseries this insect prefers apple but it also feeds in great abundance on Norway maple and various oaks. Among field crops it is partial to alfalfa, clover, potato, and beets, in about the order named. A list of all host plants reported, upon the majority of which the writer has noted this insect feeding, follows: Acer negundo, box-elder. Acer platanoides, Norway maple. Althea rosea, hollyhock Amygdalus persica, peach. Apium graveolens, celery. Avena sativa, oats. Beta vulgaris, beets. Betula sp., birch. Cannabis sativa, hemp. Castanea sp., chestnut. Corylus americana, hazelnut. Crataegus sp., hawthorn. Cydonia oblonga, quince. Dahlha sp., dahlia. Gramineae, grasses. Hamamelis virginiana, witch-hazel. Hicoria pecan, pecan. Juglans nigra, black walnut. Juglans sp., walnut. Medicago sativa, alfalfa. Phaseolus vulgaris, beans. Populus sp., poplar. Prunus virgiamiana, choke-cherry. Prunus pissardi, purple-leaved plum. Prunus spp., cherries and plums. Pyrus baccata, Siberian crab. | Pyrus communis, pear. Pyrus malus, apple. Quercus spp., oaks. Rheum rhaponticum, rhubarb. Rhus cotinus, smoke-tree. Ribes oxyacanthoides, gooseberry. Ribes rubrum, currant. Rubus spp., blackberry and raspberry. Rosa spp., roses. Secale cereale, rye. Solanum tuberosum, potato. Sorbus americana, mountain ash. Sorghum sp., sorghum. Syringa sp., lilac. Tilia americana, American linden. Trifolium sp., clover. Ulmus americana, American elm. Viburnum sp., snowball. Vitis spp., grapes. Zea sp., corn. a BULLETIN 805, U. S. DEPARTMENT OF AGRICULTURE. CHARACTER OF INJURY. The injury caused by the apple leafhopper to nursery apple trees is due to the feeding of the nymphs and adults on the underside of the tender terminal leaves from which they extract the plant juices. As a result of this attack the leaves become undersized and curled (Pl. I, B), causing a decided check to the growth of the new wood. The curling begins at the apex and extends toward the base of the eaves, the lower surface always being rolled in. This type of injury differs from aphis leaf-curl in that aphids roll the leaves more tightly and curl them from the sides instead of from the tips. During the progress of the injury produced by Empoasca mali the leaves become wrinkled and the loss of sap finally causes the tips to dry up and turn brown. (See Pl. II, fig. 2.) The nymphs, because of their greater numbers and due to the fact that they spend the entire nymphal period on a few leaves only, cause more serious injury than do the adults. The latter feed only for a short time, being principally engaged in egg-laying, and during this period they fly from one tree to another. Injury by the feeding of the adults, therefore, is of little importance when compared with the local- ized injury produced by thenymphs. Consequently, the stunted ter- minal growth is most apparent at the time when the nymphs are most abundant on the foliage. As the nymphs gradually disappear the terminal shoots seem to revive and develop normal leaves above the stunted ones. (See Pl. I, A.) At the time of infestation by the next brood of nymphs, however, a similar check to the new terminal growth is produced, Thus retardation in growth occurs periodically throughout the season corresponding to the periods of infestation by the successive nymphal broods, while intervening between each infes- tation there is a short period during which the terminals maintain a normal growth. Although the different broods of nymphs over- lap slightly the successive checks in terminal growth usually are well defined. In the vicinity of West Chester, Pa., there are three broods during the season and three corresponding checks in the terminal growth. The first growth-check takes place during the latter part of June when the first nymphal brood is feeding; a second and a third check appear during the latter part of July and August, respectively, at the time when the second and third broods of nymphs are most active on the foliage. The first brood is the most abundant on apple and consequently causes more injury than do either of the two fol- lowing broods. Adults of the first brood do not confine their activ- ities to apple alone, as many scatter to other host plants to feed and Oviposit. Bul. 805, U. S. Dept. of Agriculture. PLATE I. THE APPLE LEAFHOPPER (EMPOASCA MAL!). A, Terminal leaves of apple shoot outgrowing injury by the leafhopper; B, curled condition of terminal leaves caused by the leafhopper. PLATE Il. Fig. |1.—CAGES USED FOR REARING THE APPLE LEAFHOPPER IN NURSERY, WeEsT CHESTER, PA. Fic. 2.—TERMINAL LEAVES OF NURSERY APPLE TREES CURLED BY THE APPLE LEAFHOPPER. THE APPLE LEAFHOPPER. Bul. 805, U. S. Dept. of Agriculture. PLATE III. aR \w \ NK SF Mu SS ~| OL) OGG AU ye ly! Te EDEL 1 ep / Oo My U 10, THE APPLE LEAFHOPPER. A, First nymphal stage; B, second stage; C, third stage; D, fourth stage; E, fifth stage; F, side view of fifth stage; G, adult; H, front view of head of adult; J, eggs in tissue on underside of apple leaf; J, curled condition of terminal leaves due to attack by the apple leafhopper on apple. TWO LEAFHOPPERS INJURIOUS TO APPLE NURSERY STOCK. 5 As a result of the continued checking of the growth, due to the in- festation of the apple leafhopper, nursery apple trees often require an additional year’s growth before they become of marketable size. EXTENT OF INJURY AND INFLUENCING FACTORS. The extent of injury varies according to the age of the nursery stock and according to the differences in the character of growth of apple varieties. Seedlings and the initial growth of buds and grafts are very seriously injured. Nursery stock at this stage is in its most critical period of growth and is injured very easily. Furthermore, any injury at this stage is not readily outgrown. After the first year’s growth the more vigorous varieties become partially immune to serious injury and succeed in maintaining a satisfactory growth, while slow-growing and tender-leaved varieties are at all times badly injured by the attack of this insect. This is easily understood since, even under normal conditions, the latter make but a very ordinary growth and are entirely unable to with- stand a serious check. Among the varieties most severely injured in Pennsylvania nurseries Red Astrachan, a particularly slow grower during the first two seasons, ranks first, followed by Smith’s Cider, Starr, Early Harvest, Summer Rambo, Delaware Winter, Wagoner, Golden Russet, Early Ripe, Wealthy, and Alexander. DESCRIPTION OF STAGES. Eaa. PIT: The egg is elongate, subcylindrical in form, very delicate, slightly curved from end to end, somewhat rounded at both ends but more so at the anterior one. When first deposited 1 is rather transparent but in a few days it changes to a pale yellow color, while a small white cap forms at the anterior end through which the red eyes of the immature nymph are perceptible. Average length of 15 eggs 0.82 mm., width 0.25 mm. NYMPH. Pl. II, A-F. First instar.—Color pale white, changing to a light yellowish green after feeding. Eyes dull red. Small pale spines on the dorsal side of the head, thorax, and abdomen; the latter with four spines to each segment arranged in two longitudinal rows along each side, one spine situated dorso,laterally, the other ventro-laterally. Posterior margin of metathorax blunt. First two segments of antennz pale, the remainder dusky. Average length of 16 specimens 1 mm. Second instar.—General color light yellowish green. Eyes lose some of their red color. Posterior border of metathorax sharp in outline. First two segments of antenne light yellow, remainder dusky. Average length of 16 specimens 1.30 mm. Third instar.—General color pale yellowish green. Eyes almost pearl white. Body more robust than in first two stages. Wing pads appear as lateral buds extending 6 BULLETIN 805, U. S. DEPARTMENT OF AGRICULTURE. to the hind margin of the first abdominal segment. Spines darker and more prominent. Average length of 16 specimens 1.85 mm. Fourth instar.—Head and thorax yellowish green; abdomen yellow in color. Eyes pearl white. Wing pads extend to hind margin of second abdominal segment. Spines prominent. Average length of 16 specimens 2.1 mm. Fifth instar—Head and thorax pale green; abdomen yellow. Eyes dull white. Wing pads extend to or nearly to the hind margin of the fourth abdominal seg- ment. First two antennal segments green, remainder dusky. Body broader than in previous stage. Average length of 16 specimens 2.6 mm. ADULT. Pl. II, G, H. General color of adult pale green; face with a white median longitudinal line in older specimens but composed of a series of white spots in newly hatched individuals; median line extending from a point midway between the ocelli to a point half-the distance to lower margin of clypeus; two short white diagonal bands on each side of median line, the lowerone the smaller; ashort white line, often merely twospots, beyond the diagonal and just above the antenna; a faint white line midway between the ocellus and eye; antenne 1 mm. in length, arising near the lower frontal border of the eyes; clypeus one-third longer than broad; lorze narrow, not reaching the tipsof clypeus, con- cave below eyes; genz almost as long and half as broad as clypeus, with one or two faint white spots. Vertex dark green with a median white line, narrowest in middle, its length equal to distance between the ocelli; a white band on each side, dorso-lateral and diagonal to median line. Two ocelli present, marked by two white spots and situated on frontal margin of vertex, their distance apart equal to twice that from the eye to the ocellus; eyes dull white, reddish brown after death. Pronotum pale green, hind margin very pale, with eight white spots along the frontal margin, the last spot at each end small and often fused with the one next to it so as to form only six spots; mesonotum with two parallel white longitudinal lines centrally located and con- nected by a traverse one in the form of a letter H, a faint white diagonal line present on each lateral margin; scutellum small with a large white triangular area in the center and a small spot on each side along the frontal margin. Abdominal segments yellow- ish green with transverse yellow stripes on their hind margins, anal segment dark green. Wings semitransparent, pale yellowish green. Legs green, tarsi dusky at the tips. Sexual appendages ciliated in both sexes. Average length of 16 specimens 3.12 mm. ALLIED SPECIES. Three other species of Empoasca were found associated with E. mali on the foliage of nursery apple trees at West Chester, Pa. These species were determined by the late Otto Heidemann, of the Bureau of Entomology, as follows: HE. birdi Goding, FE. flavescens (Fabricius), and FE. unicolor Gillette. Birdi and flavescens are very closely allied species, the former being considered by Gillette to be merely a color variety of the latter; these two species resemble mali quite closely and they may be easily mistaken for it. Unicolor, on the other hand, differs markedly from any of the above three and is readily distinguished from them. Birdii differs from mali by its smaller size and paler color, by the presence of smoky markings on the elytra, and by the three white spots on the pronotum. No attempt was made to study the life history and habits of birdw but they are probably much the same as those of mali. From TWO LEAFHOPPERS INJURIOUS TO APPLE NURSERY STOCK. 7 field observations it was-found that this species hibernates in the adult stage in woodlands near the nursery at West Chester. The adults become active in the spring about a week earlier than mal, confining their feeding at first to the foliage of skunk cabbage. From this plant they scatter to grasses and weeds beneath the apple trees in the nursery a few days prior to the first appearance of mali. During the early spring they prefer to feed on any low green vegeta- tion in the nursery row, and never become abundant on the foliage of apple until about mid-season. At this time they appear in num- bers associated with mali on the terminal leaves. The extent of damage caused by birdia is small compared with that caused by the common apple leafhopper, and for this reason little attention has been paid to it heretofore. Flavescens differs from birdw by the absence of the characteristic white markings of the pronotum and the smoky bands crossing the elytra. This species is allied very closely to birdii in appearance, and proba- bly im habits and life history, but it is less abundant on the apple. Unicolor is readily separated from mali by the absence of the conspicuous white markings of the face and the notum, by its greater length and robustness, and by the presence of a pale white spot on the middle of the anterior margin of the pronotum and a blue blotch on the scutellum. Tew field observersations were obtained in regard to the habits of umcolor. The nymphs of the first brood were found on apple at approximately the same date and about as abundantly as those of malt at Hagerstown, Md. The adults of this species do not confine their attack to the terminal leaves, being found more frequently on the lower part of the trees. This species was taken in scant numbers on apple in the vicinity of West Chester and the injury caused by it was negligible. LIFE HISTORY AND HABITS. METHODS OF StTuDyY. In studying the life history of the two species of apple leafhoppers concerned in this bulletin all data were obtained under outdoor conditions by rearing the insects on young apple stock in the nursery row. Seedlings were planted out early in the spring of 1915 and again in 1916 on a plot of ground at one end of a few nursery rows. Riley cages and arc-light globe cages (Pl. II, A) were used for obtaining records of the length of the egg stage, the extent of repro- duction per female, and the longevity of adults of the different broods. The globe cages were well shaded from the sun by means of large muslin covers over their tops, while ventilation was obtained both from above and below. With the use of such cages practi- cally normal conditions were secured for the rearing of the leafhopper 8 BULLETIN 805, U. S. DEPARTMENT OF AGRICULTURE. material. The plants were encaged before the hibernating adults made their appearance in the nursery, thereby preventing outside infestation. Special cages were constructed for experiments in determining the length of the nymphal stages. Various types of cages were tried in an effort to secure one in which the nymph could’ be reared under as nearly normal conditions as possible. The type of cage finally decided upon was made as follows: A piece of thin sheet-cork was cut about 2 inches square, in the cen- ter of which a 1-inch square hole was made. White muslin cloth was stretched tightly over one side of the cork and glued fast so as to cover the center hole. Heavy wadding cut to the shape of the cork, but leaving the center open, was glued to the otherside. With the muslin side out, the cage was then placed over a newly hatched nymph on the lower surface of a leaf. A square of stiff cardboard of the same size as the cork was placed on the upper side of the leaf, and the cardboard, leaf, and cage were fastened together by paper clips. The young nymph within the cage received ventilation from both sides, through the porous wadding and through the muslin top. The leaf tissue was protected against injury by the cardboard on its upper surface and by the wadding on its lower surface. The nymph was examined daily by removing the paper clips and lifting the cage slightly; in this manner a record of the molts was obtained. Although this cage was a little heavy when used on the small leaves of seedlings, it proved satisfactory when fastened to the larger leaves of two-year trees. For this reason the nymphal stages were obtained by transferrmg newly hatched nymphs from globe cages to the cork cages on uninfested leaves of older trees in the nursery row. NUMBER OF GENERATIONS. There are three generations of the apple leafhopper at West Chester, Pa. These generations overlap slightly but they are easily distin- guished by the resultant injury caused by each. The first generation, covering the period from the time of egg deposition by the overwin- tered females to the death of the first-brood adults, extends from the last week in May to the first week in August. The second generation covers the period from the first week in July until the latter part of September. The third generation, including the hibernating adults, lasts from the first week in September until the early part of July of the following season. Adults of this generation hatch during the first week in September and remain on the trees until late in November when.they seek shelter for the winter. In the spring of the following year overwintered adults are found on the trees from the last week in May until death, which occurs during June and early July. TWO LEAFHOPPERS INJURIOUS TO APPLE NURSERY STOCK. 9 Forbes and Hart (10) in 1900 mentioned the occurrence of four or more generations in Illinois. In 1908 Washburn (15) suggested that there were two and possibly three generations in Minnesota. R. L. Webster (18) in 1910 recorded four generations at Ames, Iowa. EK. H. Gibson, of the Bureau of Entomology, has noted as many as five generations in southern Missouri, and six in southern Mississippi. THe Eaa. The eggs are laid singly in the sides of the mid-vein and occasionally in the smaller veins of the terminal leaves. They are deposited in pockets just under the epidermis, usually lying in a longitudinal position. It is very difficult to locate the eggs as they are the same color as the tissue in which they are embedded, while the epidermis under which they are hidden is covered by the pubescence of the leaf. When the pubescence is removed, the tissue covering the egg appears slightly distorted and eventually becomes discolored. In making dissections of the leaf tissue the delicate egg is often crushed, where- upon the egg contents may be mistaken for the plant juice in the vein. When ready to hatch, the immature nymph pushes its head through the anterior end of the eggshell and forces a tiny hole in the thin epidermal leaf-covering, slowly drawing its body free from the enveloping tissue. Eggs of Hmpoasca mali have been found in the leaves of the follow- ing host plants: Apple, pear, peach, plum, cherry, quince, alfalfa, beet, and potato. Adults of all three generations deposit summer eggs in leaves in the manner mentioned above. Washburn (15) stated in 1908 that the last-brood adults of this species deposit winter eges under the bark of nursery apple trees in Minnesota, and that the nymphs hatch- ing therefrom the following spring attack the lower leaves of the trees. Webster (18) in 1910 made similar observations in Iowa. At West Chester, Pa., the apple leafhopper certainly does not pass the winter in the egg stage. Several experiments were made in the attempt to obtain winter eges by confining numerous pairs of third-brood adults in cages, but all proved unsuccessful. Field observations for two seasons on several thousand trees also substantiate the above view. However, winter eggs of the rose leafhopper (which will be treated later) were found in abundance in this locality, the nymphs of which confine their feeding to the lower leaves of the trees. THe NympH. The newly-hatched nymphs are very small, wingless, white in color, and of the same form as the adults. Immediately after hatching they settle down to feed, inserting their minute beaks in the leaf tissue and sucking the plant juices. A day or two after taking food into 13281622 199 10 BULLETIN 805, U. S. DEPARTMENT OF AGRICULTURE. their bodies the young nymphs change to a pale green color, which is the characteristic color during the remainder of their nymphal life. The nymphs pass through five stages of development before they reach maturity, molting and increasing in size at the completion of each stage. The nymphs are very agile in their movements and run in a zig-zag or sidling manner; only fourth and fifth stage nymphs are able to hop. The first nymphs of the season appear on the trees about June 1, and the nymphal infestation is at its height about three weeks later. THe ADULT. The adults are very active, especially on warm, sunny days, when they rise from the trees in swarms at the least disturbance. During flight the hoppers seldom rise over the tops of the trees but fly sidewise to the next nursery row. Records have appeared stating that this insect is strongly attracted to artificial hght, but this view is contrary to observations made by the writer. Among the leafhoppers found swarming around electric lights the two allied species F. flavescens and EH. birdii were far more abundant than this species. The overwintered adult leafhoppers become active during the warm days abovt the middle of May. Upon leaving their hibernating places they immediately disperse to apple blocks in the nursery. The first adults of the season appearing on apple stock in the nursery were found on May 18; by June 1 they become quite abundant on the foliage in this section. For several days they confine their activities to feeding on the underside of the terminal leaves. After feeding for about a week the adults mate and soon begin depositing the first- brood eggs. Adults of all three generations have the same habits on apple. Third-brood adults feed on apple foliage in the fall until cold weather sets in. Prior to going into hibernation they collect on the lower leaves of the trees and on several varieties of low-growing weeds in the nursery row, being especially abundant on sorrel (Rumez sp.)- LONGEVITY OF OVERWINTERED ADULTS. Data on the length of life of the adult apple leafhoppers were ob- tained with great difficulty, due to their activity. A Riley cage was used in this experiment in which 50 adults were confined on a young apple tree. The newly transforming nymphs were removed from the foliage from time to time to prevent confusing them with the adults. During the progress of the examinations a few adults made their escape.