U. S. Department of Agriculture). ing summer were eaten off (see Plate VI, c), and raspberry plants near by had also been stripped. Two species of cutworms were responsible, and when reared, the adults proved to be Agrotis uni- color Walker (formerly Noctua eland estina Harris) and Noctua fennica Tausch. In May, 1926, similar injury occurred on grafts set in young orchard trees in Wallingford, and was caused by the dingy cutworm, Fcltia subgotJiica Haworth. In May, 1922, rasp- berries in East Haven were injured by cutworms, and from the material two moths were reared, Par agrotis messoria Harris and P. tessellatus Harris. The same season larvae of Noctua c-nigrmn INSECT PESTS OF NURSERY STOCK 131 Linn, injured strawberry plants in a field near New Haven. As the injury is seldom noticed until too late, treatment is ineffec- tive. In certain cases a liberal application of lead arsenate may protect the plants. (Bulletin 247, and Report for 1922, pages 373, 375 ; Bulletin 275 and Report for 1925, page 324; Bulletin 285, and Report for 1926, page 2,^6). New York Weevil {ItJiycerus noveboracensis Forst.) Though the injury is not common, occasionally young pear and plum trees are injured by this weevil, which eats into the bases of new shoots, sometimes nearly severing them. In a young orchard in Wallingford in 1908, injury by this weevil was quite prominent Fig. 18. Imported currant worm. Fig. 19. Round-headed borer. the last week in May. The insect is a snout beetle about half an inch in length, gray or slightly reddish, marked with quadrate black spots. Spraying with lead arsenate proved an effective remedy. (Report for 1908, page 845). Leopard Moth. See page 120 Apple Tree Borers There are two common species of borers which attack apple trees in Connecticut. They are known as the flat- and round- headed borers. The round-headed borer, Saperda Candida Fabr., usually attacks the main trunk of the trees near the base. The adult is one of the long-horricd beetles and may be easily recognized by two straight white lines running lengthwise on its back (see Fig. 19). The eggs are laid during the summer, and the young borers tunnel just 132 CONNECTICUT EXPERIMENT STATION BULLETIN 292 under the bark until winter. The following year they tunnel into the sapwood and the third year feed directly in the solid wood. By this time the borers are quite large and do much damage to young trees, often killing them. The best remedy is to cut them Out with a knife. Often a wire with a barb near the end is very useful to push into the tunnels and draw out the borers. The insect sometimes attacks other trees beside apple, quince being a favorite host, as well as Crataegus and mountain ash. The pres- ence of borers may be noted by sawdust on the ground at the base of trees, which the borers have pushed from their burrows. (Report for 1907, page 333). The flat-headed apple tree borer is the larva of a Buprestid bee- tle, CJirysobothris fcmorata Fabr. As a rule, this insect attacks only trees that have been weakened by some other cause. It attacks a large variety of trees and has often been found in dry cordwood. The borer seldom produces any visible castings, but its presence may be noted by a darkened and depressed area over the gallery. The larva when full grown is about an inch long and has a broad, flat head, from which it derives its name. It normally lives but one year in the tree, although under certain conditions it may live two years. The remedy is to cut out borers when found and to keep trees in good condition by proper cultivation and fertilization. (U. S. Farmers' Bulletin 1270, page 73). Oriental Peach Moth (Laspeyresia molesta Busck) This pest from the Orient is believed to have been brought into the United States on flowering cherries from Japan and has now spread throughout the Atlantic States as far north as Massachu- setts and as far west as the Mississippi River. It has also beer found in Ontario, Canada. There are three generations each sea- son, and the larvae live through the winter in inconspicuous cases on the bark. The larvae tunnel in the twigs (see Plate V. b). causing the tips to die and the lateral buds to develop and form thick bushy tops. Though primarily an orchard pest, it often at- tacks nursery trees. No good remedies are known. (Reports for 1925, page 280; 1926, page 234). Peach Borer (Synanthedon exitiosa Say) The adult of the peach borer is a wasplike moth. It lays its eggs in midsummer, and the borers hatching from then live in the trunks and often the larger roots until the following June or Juty, when they pupate in their burrows. The adults emerge to lay eggs for the next generation. This borer is sho\rn on Plate VI, d. INSECT PESTS OF NURSEKV STOCK 133 The only satisfactory remedy on nursery trees is to cut open the burrows and kill the borers. A small piece of wire is very useful to insert into the burrows to pull the borers out, saving consider- able cutting of the trunk of the tree. The injury may easily be seen by masses of gum at the base of the tree. This gum is often full of small particles of wood which the borer pushes from the burrow. Older peach trees may be treated with paradichloroben- zene, but this treatment is not safe on nursery trees. (Report for 1909, page 359). Shot Hole Borer {Scolytus rugiilosus Ratz.) This insect attacks most of the fruit trees which are normally grown in Connecticut. The injury is caused by the larva of a small beetle which lays its eggs under the bark of weakened and sickly trees, rarely attacking vigorous, healthy trees. The eggs Fig. 20. Shot-hole borer. hatch into small white grubs which bore just under the bark and slightly into the wood. The larvae live over the winter in these galleries and during the following summer transform to the adult stage and emerge from the trees, leaving small round holes in the bark. The bark of the infested trees looks as though it had been riddled by shot, and this fact gives the insect its common name. Occasionally the beetles tunnel at the base of small twigs, which may weaken the tree to such an extent that the grubs may live under the bark. This insect is shown in Fig. 20. The only remedy is to cut out infested trees or branches and burn. Much can be done to prevent injury by removing sickly trees in or near the nursery and keeping all fruit stock in a vig- 134 CONNECTICUT EXPERIMENT STATION BULLETIN 292 orous growing condition by the application of nitrogenous fer- tilizer and by cultivation. Imported Currant Borer {Sesia tipuliformis Clerck) The adult is a clear- wing moth which appears in June, and the female lays eggs singly on the bark. The young larvae enter the stem and bore upward or downward in the pith, kilHng the stem. They are nearly full grown when winter approaches and hibernate in the burrows. The following May, each larva tunnels outward but leaves the burrow covered by a thin layer of bark. It then pupates in the burrow, and in June the moth emerges, leaving the pupa skin projecting from the cavity. There is only one brood each season. Infested canes appear sickly and should be cut oft and burned before June i to kill the borers before the moths emerge. (Fruit Insects, page 339). Fig. 21. Green apple aphid. Eggs 011 twig; aphids on leaf. Green Apple Aphid (Aphis point DeG.) This insect probably causes more injury to apple trees in the nursery than any other insect attacking apple trees in Connecticut. This was particularly true during the early summer of 1927, when these insects were very numerous and caused much injury by stopping growth and distorting young apple trees in Connecticut nurseries. The insect passes the winter in eggs laid on twigs. The eggs are yellowish-green when laid, becoming glossy black. The young aphids hatch early in the spring, as soon as the buds begin to open, and start to feed on the young, unfolding leaves. No eggs are laid during the summer generations, the young aphids being born alive, and are ready to feed immediately. There are from 9 to 17 broods INSECT PESTS OF NURSERY STOCK 135 produced during the season, following which the sexual individuals appear and deposit the overwintering eggs. This aphid is shown on Plate VII, b, and in Fig. 21. Thorough spraying of the trees when the buds are opening in spring, using lime and sulphur at the rate of one part to nine parts of water, plus one pint of nicotine sulphate to every one hundred gallons of water, will be found of great value. Some of the miscible oils are also very good for this purpose, if the direc- tions of the manufacturers are followed. Spraying at this time with either of these sprays will also help in the control of San Jose scale. During the summer, after the leaves have become curled, it is almost impossible to hit the aphids with any sprays. It is therefore necessary to dip the tips of the branches — where most of the aphids are found — in a pail of spray material con- sisting of one pint of nicotine sulphate to one hundred gallons water. It is very important that about four pounds of soap, pre- viously dissolved in hot water, be added to the mixture. Other aphids may often be found on apple stock, but the above treatment is effective on all kinds of plant lice. Woolly Apple Aphid {Eriosoma lanigcrum Haus.) This aphid differs from other aphids in the fact that it attacks its host plants both above and below the ground, and those that are above ground are covered by a white wax secretion resembling cotton (see Plate VII, c). These aphids often cluster in wounds, such as scars, cankers, and other injuries. The root form of this insect causes the roots to be deformed and covered with small galls. The life history of this aphid is rather intricate but may be briefly outlined as follows : The eggs are laid in the crevices of the bark on elm trees in September and hatch in early spring. The aphids hatching from these eggs are wingless females and their young are also wingless, but the next brood produces winged adults which migrate to apple and somiCtimes to pear, quince, mountain ash and Crataegus. There are three summer broods, and in Au- gust winged females appear which migrate back to elm and lay winter eggs. The aerial form may be controlled by spraying with kerosene emulsion or with nicotine sulphate and soap. The underground forms are harder to kill, as it is almost impossible to make spray permeate the ground sufficiently to kill the aphids. Carbon disul- phide emulsion has been used with some success. One-half pound of carbon disulphide emulsion in four gallons of water poured into a shallow trench around the trees will kill the underground forms. (Report for 1924, page 308). 136 CONNKCTICL'T EXPICRI.M KNT S'lATION BULLETIN 292 Black Cherry Aphid {Myzus cerasi Fabr.) The black cherry aphid is often very abundant on sweet cherry stock in nurseries. It is a black insect with a rounded abdomen, giving it a more or less globular appearance. The eggs are laid upon cherry twigs in the fall and hatch early in the spring, often before the cherry buds open. They are able to withstand freezing, and as soon as warm weather comes and the buds open, they begin to feed and reproduce. This usually takes place in two or three weeks. Later broods become mature in less than a week. Some of the individuals of the later broods become winged and migrate to pepper grass, where they continue to repro- duce until fall. They then migrate back to cherry and lay the over- wintering eggs. Not all of the aphids migrate from cherry, and some can usually be found on it all summer, although during the latter part of the season they may not be very plentiful. Control measures given for green apple aphids will be found useful for the cherry aphids. (See page 135). (U. S. Farmers' Bulletin 1128, page 20). Currant Aphids There are several species of aphids causing injury to currant foliage. Their life histories are very similar and the same control measures would be equally effective on all species. Perhaps the most common species in Connecticut is called the currant aphid, Myzus ribis Linn., which causes the terminal leaves to become much distorted, and little pits or pockets are formed on the under side of the leaves. The upper surface becomes more or less reddish m color, which is noticeable some distance away. When plants are heavily infested, these leaves fall, causing the plants to make a poorer growth. The stem mothers hatch from eggs on currant twigs soon after the leaves develop in spring. Some of the young from the stem mothers develop wings and migrate to motherwort, hedge-nettle, and other related plants. The wingless forms remain on currants and continue reproduction. In each generation some winged in- dividuals appear which migrate, but v/ingless forms are found on bushes until late summer. Early in October, migrants return and deposit the sexual females, which. wlT,en mature, mate with the winged males, and eggs are laid upon the twigs. Spraying with nicotine sulphate and soap when the buds are opening will kill the stem mothers, or a later spray of the same material, directed upward to hit the aphids on the under side of the leaves, will hold the insects in check. (U. S. Farmers' Bulletin 1128, page 28). INSECT PESTS OF NURSERY STOCK 137 San Jose; Scale (Aspidiotiis perniciosus Comst.) A number of years ago this insect was considered one of the most destructive scales infesting nursery stock. It is thought to have been introduced from China and was first found in this coun- try in San Jose, CaHfornia, about 1870. Since that time it has been spread through the principal fruit and nursery districts of the United States. The general use of dormant and summer sprays, together with its natural enemies, has so reduced its numbers that it is not con- sidered so serious a menace as formerly. Occasionally, however, nursery trees are nearly killed by this insect. This is particularly true of fruit stock which has been heeled in for a few years ; it invariably becomes infested with scale and must be destroyed. Apple, pear, and peach trees are its favorite food plants, but other fruit trees, as well as shrubs and shade trees, are often attacked. The scale or covering beneath which the insect lives is circular, about the size of a pin-head, grayish in color, with the central por- tion raised, and is shown in Fig. 22, and on Plate VII, a. The best method of control is to spray the trees while dormant with a lime-sulphur solution, using one part to nine parts of wa- ter, or with one of the many miscible oils now on the market, fol- lowing the manufacturer's directions. (U. S. Farmers' Bulletin 1270, page 62). Oyster-Shell Scale. See page 123 Scurfy Scale {Chionaspis furfura Fitch) Apple and pear trees, as well as other common deciduous trees and bush fruits, are often attacked by the scurfy scale, which re- tards the growth and sometimes causes the death of the trees if the infestation is severe. This insect is a native of the United States, but is most common in the New England and Middle At- lantic States. It is easily recognized by its dirty-white color and pear-shaped scale in the female, and the white elongated scale of the male, as shown on Plate VII, f. The insect winters in the egg stage, the eggs being found under the female scales. The eggs and the young scales are purplish, tinted with red, and hatch the last week of May. In the North there is but one brood each season, but farther south there may be two or three broods. A dormant spray of lime and sulphuf, or a miscible oil, applied as for San Jose scale, will usually control the scurfy scale. (U. S. Farmers' Bulletin 1270, page 65). 138 CONNECTICUT EXPERIMENT STATION BULLETIN 292 Leaf Hoppers on Apple There are two species of leaf hoppers commonly found on apple stock in Connecticut nurseries. They are quite similar in appear- ance but their life histories, as well as the injury they cause to growing- apple trees, are quite different. The leaf hopper causing the most injury to young apple trees is known as the apple leaf hopper, Empoasca mali LeBaron, shown in Fig. 23. The other is commonly known as the rose leaf hop- per, Empoa rosae Linn. The injury caused by the former is very noticeable on young trees, where it attacks the tender terminal leaves, causing them to become reduced in size, curled, and mis- shapen. The effect of feeding by the insects is to make the tips and edges of the leaves brown and dry. Fig. 22. San Jose scale. Fig. 23. The apple leaf hopper, in its different stages. (After Wash- burn, 9th Report State Entomolo- gist of Minnesota). The life history of the apple leaf hopper is as follows : The adults pass the winter under fallen leaves or any other convenient shelter. When the weather becomes warm in the spring, they leave their hibernating quarters and go to the young apple leaves to feed. Later the eggs are laid under the lower epidermis of the leaves and hatch in a short time. Three generations are pro- duced each year, the last, one hibernating. The so-called rose leaf hopper makes the apple leaves appear more or less stippled or mottled. Leaves seriously infested by this insect are unable to function properly, and in extreme cases fall to the ground, interfering with the proper growth of the trees. This insect is believed to have been introduced from Europe, perhaps on nursery stock, and is now widely distributed through- out the United States. Among its food plants, besides apple, are grape, raspberry, currant, gooseberry, blackberry, elm, oak, and others, though rosaceous plants are preferred. INSECT PESTS OF NURSERY STOCK 1 39 The leaf hopper passes the winter in the egg stage. The eggs are deposited beneath the bark of apple and rose, producing tiny, raised, blister-like spots. They hatch in early spring, and the young are mature early in summer. The eggs for the second brood are deposited in the veins of the leaves. There are two broods each season. Control measures are the same for both species : A spray of one pint of nicotine sulphate in a hundred gallons of water in which four pounds of soap have been dissolved will be found very effec- tive if applied when the first generation is still young. The spray must strike the underside of the leaves where the young leafhop- pers feed. (U. S. Farmers' Bulletin 1128, page 26). Tarnished Plant Bug (Lygns pratensis Linn.) This insect injures peach stock by puncturing the tip of the tender new shoots, sucking out the juices, and probably injecting Fig. 24. Tarnished plant bug: adult at left: last stage of nymph at right. Enlarged about four times. (After Chittenden, Bulletin 43, Bureau of Entomolog)', U. S. Department of Agriculture). some poisonous substance into the tissues, which soon die. This injury is called "stop-back" or "bush-head." Pear and apple trees, and many flowering plants are also injured by the tarnished plant bug. The female lays eggs in the tender shoots or in the petioles or veins of the leaves. The young bugs are yellowish-green and pass through five stages before the mature winged form appears. Both nymph and adult are shown in Fig. 24. There are probably several generations each year, and all stages may be found from May until November. All weeds and rubbish around the field should be destroyed by burning or plowing. Spraying heavily with nicotine solution and soap will probably kill the nymphs. (Missouri Bulletin i/O, page 17). 140 CONNECTICUT EXPIvKI.M 1-:NT STATION BULLE^TIN 292 Pear Leaf Blister Mite (Eriopliyes pyri Pag.) The pear blister mite attacks the foHage of apple and pear but rarely causes any serious injury to apple foliage. On pear it is often a serious pest, causing" a slowing up of tree growth, making undersized pear stock. It produces on the foliage small reddish or greenish galls or blisters which, after a time, turn brown, spotting the leaves with dead areas, as shown on Plate VII, e. When the galls are abundant, the tissues become dead, and the injured leaves have a brownish, shriveled appearance and often drop. This mite is of European origin, but is now widely distributed wherever pears are grown. The winter is passed in the adult stage under the bud scales. The adults are very small, elongate, whitish insects. In spring when the leaves are unfolding, the mites enter the leaves through the lower epidermis, and their activities soon produce their char- acteristic galls, in which they live and multiply. After reaching maturity, the mites desert the old galls, make new ones, and pro- duce a new generation. The process continues until cold weather, when the adults migrate. to the bud scales for the winter. Spraying while the trees are dormant with lime-sulphur solution as for San Jose scale will hold this mite in check. Summer sprays are of doubtful value, the mites being inside the leaves and pro- tected from the action of the sprays. (Report for 19 lo, page 700). European Red Mite (Paratetranychus pilosus Can. & Fanz.) The work of the European red mite was first noticed on orchard trees in Connecticut in 1920. Since then it has caused consider- able injury to orchard trees throughout the State. The presence of mites on the foliage is usually indicated by the leaves turning brown, if the infestation is severe. A light in- festation gives the foliage a sickly color and interferes with the proper functioning of the leaves. The mite has been found on apple, cherry, plum, peach, pear, rose, and elm, although most of the real injury in Connecticut has been noticed on apple. The eggs of the European red mite may be found on the branch- es and twigs of infested trees during the late fall and winter, as are shown on Plate VII, d. They are reddish in color and .15 mm. in diameter. When plentiful, they give the twigs the appear- ance of being covered with brick dust. The eggs hatch dur- ing the latter part of April or early in May, and the young mites make their way to the young leaves, where they begin to feed. They reach maturity in about three weeks and begin to lay eggs for the next brood. There are several broods in a season. INSECT PESTS OF jN'URSERY STOCK I4I The best-known remedy is to spray in early spring, just before the eggs hatch, with one of the miscible oils. Lime-sulphur may be used, but is not as effective as an oil spray. Care must be taken to spray thoroughly, hitting all the eggs. If many of the eggs are missed in spraying, they will hatch and breed fast enough, under favorable conditions, to give rise to a serious infestation later in the summer. If mites become plentiful during the sum- mer, a spraying of linseed oil emulsion will be effective, using one gallon of linseed oil and one and one-quarter pounds of soap to one hundred gallons of water. (Bulletin 252). INSECTS INJURING DECIDUOUS SHADE AND FOREST TREES Key A. Feeding upon the leaves : 1. Mining in leaves of larch Larch Case Bearer, p. 142 Mining in leaves of locust Locust Leaf Miner, p. 143 Making blotch mines in birch leaves. Imported Birch Leaf ]Miner, p. 143 2. Skeletonizing the leaves 3 Devouring the leaves, except the larger veins 5 3. On poplar and willow 4 On birch Birch Skeletonizer, p. 144 On elm Elm Leaf Beetle, p. 144 4. Small, dark blue or green beetles ; mostly bright green, 2-4 mm. long Willow Flea Beetle, p. 145 Mostly dull blue, 4-5 mm. long. Imported Willow Leaf Beetle, p. 145 Larger beetles, 7-10 mm. long, light brown, marked with black longitudinal lines, on poplar Cottonwood Leaf Beetle, p. 145 Marked in the form, of irregular black dots, Spotted Willow Leaf Bettle, p. 145 5. Forming webs or nests 6 Not forming webs or nests 7 6. Large loose webs on ends of branches in late summer. Fall Webworm, p. 120 Small close webs on twigs of poplar Poplar Tent Maker, p. 146 7. Feeding upon broad-leaved deciduous trees 8 Devouring leaves of larch Larch Sawfly, p. 146 S. Larger, hairy caterpillars, non-loopers 9 Smaller, smooth caterpillars which loop in crawling, Cankerworms, p. 120 g. Conspicuously marked with black, white, or yellow tufts of hairs, Tussock Moths, p. 121 Caterpillars gray or brown, Avith two rows of dorsal tubercles ; first five pairs blue, remaining six pairs red.. Gipsy Moth, p. 122 142 CONNECTICUT EXPERIMENT STATION BULLETIN 292 B. Tunneling in the Wood : 10. Larvae white, without legs il Larvae white with dark brown spots, with legs, Leopard Moth, p. 120 11. Round-headed larvae 12 Flat-headed larvae in white birch Bronze Birch Borer, p. 147 12. Tunneling in base of linden Linden Borer, p. 148 Tunneling anywhere in trunk of black locust. Locust Borer, p. 148 Tunneling in trunk and branches of poplar and willow, Poplar and Willow Borer, p. 149 C. Sucking Insects : 13. Green or white, woolly plant lice, visible on leaves 14 Small red objects, hardly visible on leaves Mites, p. 150 14. Green plant lice on leaves Green Aphids, p. 150 White woolly plant lice on beech leaves. Beech Woolly Aphid, p. 151 15. Scale insects fixed on bark 16 Large brown plant lice on bark of twigs Willow Aphids, p. 151 16. Hemispherical or globular, brownish or greenish scale insects on twigs 17 Pear-shaped, white, gray or brownish scales 21 17. Scales hemispherical 18 Scales globular, on oak Oak Gall Scale, p. 151 18. Scales brown, without white wax secretion ■ 19 Scales brown, with conspicuous secretion of white wax 20 Scales greenish-j^ellow, in pits on the bark of English oak. Pit-making Oak Scale, p. 151 19. Scales large (6-8 mm.) on tulip tree Tulip Tree Scale, p. 152 Scales small (2-6 mm.), reddish-brown, on maple. Terrapin Scale, p. 152 Larger than preceding, often clustered on many different kinds of trees and shrubs European Fruit Lecanium, p. 123 20. Chocolate brown with white wax fringe in crevices of bark on elm European Elm Scale, p. 153 Medium brown on twigs of maple; white ovisac develops and becomes very prominent under posterior portion of body. Cottony Maple Scale, p. 153 21. Gray or dirty white on elm twigs Elm Scurfy Scale, p. 154 Gray or brownish, often same color as bark, on a great variety of trees and shrubs Oyster-shell Scale, p. 123 Larch Case Bearer {Coleophora laricella Hubn.) The young larvae of the larch case bearer tunnel out the outer half of each needle, and when it is completely hollowed out, cut it off at the base of the excavated portion and use the latter as a case, living in it and carrying it about while feeding. They spend the winter in these cases, fastening them to the twigs by silken threads. When warm weather comes in the spring, the larvae dislodge their cases and migrate to the leaves, upon which they feed. They also cut off other needles to enlarge their cases and continue to do this until May, when they pupate within the cases. The adults INSECT PESTS OF NURSERY STOCK 143 emerge the latter part of May and lay their eggs upon the leaves during the early part of June. The adult is a small moth with a wing expanse of about 9 mm. It is silvery grayish-brown in color with narrow front and rear wings having a long fringe. There is no practical method of controlling this insect in for- ests or large plantations, but on shade or ornamental trees spray- ing is effective. If the trees are sprayed with lime-sulphur at the rate of one part to seven parts of water before the new leaves start in the spring, many larvae will be killed in their hibernating quarters. Spraying with arsenate of lead seems to have no effect upon this insect. (Report for 1923, page 288). Locust Leaf Miner (Chalepus dorsalis Thunb.) The adult of this insect is a beetle about one-fourth of an inch in length, with head, legs, and an area along the middle of the wing-covers, black ; the thorax and remaining portion of the wing- covers are orange-red. The eggs are laid on the under sides of the leaves in May, and the larvae are miners within the leaves, and pupate there. The beetles emerge from the mines in July and fly about, soon laying eggs for the second brood, which reaches maturity in the fall. The beetles hibernate under the dead bark of trees, cracks and crev- ices, and under rubbish. Though the black locust is the preferred food plant and is therefore the most severely injured, this insect also attacks dogwood, elm, oak, beech, cherry, and several other species of trees. Locust trees may be protected from this insect by spraying with lead arsenate to which a little molasses has been added. (Ohio Bulletin 332, page 231), Imported Birch Leaf Miner (Fenusa pumila Klug) The adult of this insect is a small black sawfly which has some- how been introduced from Europe. First noticed in Connecticut in 1923, the adults were reared and identified in 1924, and the insect has now spread throughout New England and eastern New York. There are apparently three generations each year, the win- ter being passed as pupae in the ground. The larvae make blotch mines on the tender or terminal leaves, as are shown on Plate VIII, a, especially on sprouts or low trees of the gray birch, the paper birch, and the European white birch. Several larvae in a leaf unite in mining the entire leaf. No remedy is known. (Report for 1924, page 340). 144 CONNECTICUT EXPERIMENT STATION BULLETIN 292 Birch Skeletonizer (Bucculatrix canadensisella Chambers) This is a native American insect of periodical abundance, and there is an annual generation which hibernates in ribbed cocoons on old leaves on the ground. The adult moths emerge and lay eggs in June and July. The eggs hatch in 15 days, and the young larvae for the first three instars (on the average, about four weeks) mine in the leaves. They then emerge and feed upon the under side of the leaves, skeletonizing them. They molt in white, circular or oval flattened cases on the leaves. The chief food plants are the gray, paper, yellow, and European white birches. The larvae and their work are shown on Plate VIII, b. The remedy is to sprav with lead arsenate. (Bulletin 288). Elm Leaf Beetle {GaleruccUa xanthomelaena Schr.) The work of the elm leaf beetle is found in the nurseries of the State nearly every year. Some seasons it is serious and must Fig. 25. Larvae and work of the elm leaf beetle. interfere with the growth of the trees. It is another insect of European origin but has been in this country for nearly ninety years, and is distributed generally throughout the eastern United States. In the early nineties many fine old elms were destroyed by this beetle in southern New England. The beetles live over the winter in houses, barns, church bel- fries and out-buildings. They leave their winter quarters in early spring, mate, and, as soon as the leaves unfold, eat small round holes in them. In May or early June, the females lay small clus- ters of yellowish eggs on the under side of the leaves. Each female may lay five or six hundred eggs. In about a week the eggs hatch and the young larvae or grubs feed on the under side of the leaves, as shown in Fig. 25, and on Plate IX, b, become INSECT PESTS OF NURSERY STOCK 145 full grown in about three weeks, and crawl down the trees to pupate on the ground. The pupa stage lasts about ten days. Then the adult beetles emerge and lay eggs for the second generation, which seldom does much damage in Connecticut, and go early into winter quarters. There is no reason why this insect should be a serious pest in nurseries because it is easily killed by an application of arsenate of lead spray, using two pounds to fifty gallons of water. The best time to apply this is soon after the eggs have hatched, which is around the first of June. (Bulletin 155). Willow Flea Beetle (Crepidodera helxines Linn.) This is a small, bright green or occasionally blue, metallic, jump- ing beetle, with rather prominent punctures on the wing-covers, and about one-tenth of an inch in length. It is often rather abundant on willows in nurseries, and the beetles eat many round holes in the leaves. It lives through the winter in the adult stage, but its life history is not well known. Spraying the foliage with lead arsenate is the remedy. (Kentucky Bulletin 120, page 61). Imported Willow Leaf Beetle (Plagiodera versicolora Laich.) This insect has recently become established in the United States in the vicinity of New York City. It was first found in Connecti- cut at Greenwich in 192 1. At that time the beetles and larvae were quite numerous and were defoliating willows. Since then the insect has spread over the State and can be found in nearly all nurseries where willows are grown. The beetles appear late in April or early May and feed for some time ; then deposit eggs. The beetles are moderately stout, about one-eighth of an inch long, and of a dark, metallic-blue color. When the eggs hatch, the young, bluish-black grubs feed on the under side of the leaves, often skeletonizing them. This insect and its work is shown on Plate IX, c. Spraying with lead arsenate is effective. (Report for 1921, page 195). Cottonwood Leaf Beetle {Lina scripta Fabr.), Spotted Wil- low Leaf Beetle {Lina lapponica Linn.) These insects are well-known pests of poplars and willows. In Connecticut most of the injury is done to Lombardy and Carolina poplars. Both species of beetles cause injury, but Lina scripta is the more common in this State. 146 CONNECTICUT EXPERIMENT STATION BULLETIN 292 The life history, habits, and the control measures are about the same for both species, so they may be treated together in this paper. The beetles appear early in the spring when leaf growth starts, and begin to feed on the foliage. In a short time oviposition takes place, and the reddish-yellow eggs are laid in clusters on the under side of the leaves. From these hatch small black grubs which skeletonize the under surface of the leaves. As they grow larger they eat out ragged holes in the leaves and often leave only the midribs. When full grown they pupate on the leaves and soon the adults emerge. There are three broods in a season. Spraying with arsenate of lead, using three pounds to a hundred gallons of water, will control this pest. An effort should be made to spray the under side of the leaves, as the young grubs feed only on the lower surface until they are about half grown. The smooth surface of the poplar and willow leaves causes the spray to roll off or collect in drops, but this may be overcome by adding a spreader like calcium caseinate, mixing one pound with a hun- dred gallons of the spray mixture. (Ohio Bulletin 332, pages 259, 261). Fall Webworm. See page 120 Poplar Tent-Maker {Melalopha inchisa Hubn.) The caterpillars feed gregariously upon the foliage of various kinds of poplars and willows and make small nests upon the twigs which resemble those of the brown-tail moth. Unlike them, how- ever, the caterpillars do not remain in the webs through the win- ter. There are probably two generations each year, as the moths are present in March, April, and May, and again in July and August. The full-grown caterpillar is about an inch and a half long, dark brown, with narrow yellow stripes extending lengthwise. The head and legs are black, the under surface of the body honey- yellow. The fourth and eleventh segments each bear a closely set pair of high, pointed tubercles dark brown in color and some- what hairy. Spraying with lead arsenate is the remedy. (Report for 1911, page 310). Larch Sawfly (Lygaeonemafus erichsoni Hart.) The larch sawfly was first noticed in this country in J\'Iassachu- setts in 1881. Since that time it has caused considerable injury to larch plantations. In Connecticut it has been reported from the INSECT PESTS OF NURSERY STOCK 147 northern parts of the State where larch grows naturally. Both the adults and the larvae injure trees, the adults injuring the ter- minal twigs by inserting eggs, and the larvae eating the leaves. The adult female selects the young, green, terminal shoot in which to deposit eggs, causing it to die or severely injuring and distorting it. The eggs are laid in May and hatch in about ten days. The young larvae feed on the leaves and are full grown in three or four weeks. They then make cocoons under rubbish on the ground, where they spend the winter. The adults emerge the following spring. Larvae and cocoons are shown on Plate IX, a. On small trees in nurseries, injury may be prevented by spray- ing with three pounds of arsenate of lead in fifty gallons of water. In woodlands the insect is hard to control because of the size of the trees and the difficulty in spraying. In Connecti- cut the best time to spray is early in June soon after the eggs have hatched. (Report for 1915, page 125). Fig. 26. Worl: of the bronze birch liorcr. Canker WORMS. See page 120 Tussock Moths. See page 121 Leopard Moth. See page 120 Bronze Birch Borer {AgrUns anxius Gory) Many cut-leaf white birches in Connecticut have died during the past few years as a result of the attack of the bronze birch borer. The European white birch, Betiila alba, is the species chief- ly injured. Our native birches are seldom, though occasionally attacked bv the insect. 148 CONNECTICUT EXPERIMENT STATION BULLETIN 292 Thinning of the foHage in the top of the tree is an indication of the presence of the borer. Later, the top branches die, and the following season the process continues until the tree is killed. A careful examination shows ridges or swellings on the branches one- half to one inch in diameter before anything is wrong with the foliage. Where the beetles have emerged there may be semi- circular exit holes. Injured wood is shown in Fig. 26. There is one annual generation each year. The larvae live through the winter in cells just under the bark and pupate early in May. The beetles emerge late in May or early in June and lay eggs in the crevices of the bark. The small larvae hatching from the eggs tunnel first near the bark and, as they grow larger, into the wood. Infested trees should be cut and burned before June i to pre- vent the flight of the beetles from infested trees to healthy ones. As the adults feed to some extent upon the foliage, spraying with lead arsenate early in June is recommended. (Report for 1922, page 359). Linden Borer (Saperda vestita Say) This insect often causes serious injury to young linden trees. In nurseries many have been injured at the base so that they break in wind-storms. See Plate X, b. The adult beetle is black, covered by a dense olive pubescence, and usually has three black spots on each wing-cover, though these are sometimes absent. The beetles appear during the sum- mer and after feeding on the green bark of growing shoots, leaf stems, and on the under side of leaves, they begin to lay their eggs. The females with their jaws make slight incisions in the bark where they lay their eggs. The grubs on hatching mine under the bark and into the wood. The injury takes place at or near the ground — never more than a foot from it — and some- times in the larger roots. The only remedy is to kill the borers. This may be done with a pointed knife or a wire. The borer may be extracted by means of a small wire with a barbed point like a harpoon. (Report for 1915, page 186). Locust Borer (Cyllens robiniae Forst.) The adult is one of the long-horned beetles about three- fourths of an inch long, black in color, with bright yellow bands extend- ing across the body. The insect is very destructive to our com- mon locust, Rohinia pseudoacacia, and also to the rose acacia, Rohinia hispida. The beetles appear in September, when they may be found feeding on the blossoms of goldenrod. Eggs are INSECT PESTS OF NURSERY STOCK 149 laid about that time in clusters or singly, on the roughened bark of trunks and branches. The young larvae hatching from them tunnel into the bark, where they spend the winter. In spring they resume feeding and go into the heart-wood. An enlarge- ment forms at the entrance of the burrow, and in time the trunks of young trees become much deformed ; on older trees the branch- es are injured. Successful and practical measures for the control of this insect have never been found. If only a few trees are involved, the larvae may be dug from their burrows. Repellent washes applied to the trunks of trees during the egg-laying period have proven expensive and only moderately effective. (Ohio Bulletin 332, page 316). Poplar and Willow Borer (Cryptorhynchus lapathi Linn.) This insect is one of the snout beetles or weevils and is about one-third of an inch long, dark gray in color, except the tips of the wing-covers, which are paler. (See Fig. 27). Injury is Fig. 27. Poplar and willow borer, twice enlarged. caused by both adults and larvae. The adult punctures the bark of the trees and the grubs bore into the trunk and branches. The injury, shown on Plate X, a, is greatest to nursery stock and newly set trees ; after the trees are older and well established, less in- jury occurs. The winter is passed in the larval stage within the host plant. The adults appear late in July and are most abundant in August. Mating and egg-laying take place about ten days after emergence. Infestation is indicated by dead patches of bark, dead or dying trees or limbs with irregular swellings or galls formed over tun- nels. One remedy is to cut out and burn all infested wood before May or June, to prevent the grubs from reaching maturity. Prob- ably the insect can be controlled by thoroughly coating the bark in July with arsenate of lead. Painting the trunks of trees early in April with Carbolineum or some other repellent has also been recommended. (Ohio Bulletin 332, page 319). 150 conni-xticut experiment station lulletin 292 Sucking Insects Mites Though "mites" or "red spider" are not insects, there are sev- eral species which injure the leaves of trees, causing them to turn dull and brown the latter part of the season. Mites belong to the Order Acarina (Class Arachnida) and usually have four pairs of legs, thus differing from insects (Class Insecta) which usually have three pairs of legs in the adult stage. In mite infestations pale, brownish spots are noticed on the leaves, which may later cover the entire foliage. When these spots are examined with a magnifying glass, tiny globular eggs, egg- shells, mites, and their cast skins may be seen. One of the common mites in nurseries, especially on oak and maple, is Paratefranychus bicolor Banks. The European red mite, Paratetranychus pilosus C. & F, (see page 140), which is an important pest 6f fruit trees, also occurs on elm and probably on other kinds of shade trees. The common "red spider" of green- houses, Tctranychus bimaculatus Harvey (telarius Linn.) may injure the foliage of almost any tree species. With T. bimaculatus, evidently the adults hibernate, but with P. bicolor and P. pilosus, reddish or brownish eggs are laid in the fall on the bark of the trunk and branches. On hatching in spring, the young mites find their way to the leaves. The remedies are: a dormant spray of a miscible oil (i - 15) to kill the overwintering eggs ; a summer spray of linseed oil emul- sion to kill the mites. This emulsion may be made as follows : I gallon raw linseed oil 1.5 pounds soap flakes I gallon water Dissolve the flakes in the water, stir in the linseed oil, and di- lute to make 100 gallons. (Bulletin 252). Green Aphids There are many species of green aphids attacking deciduous trees during the growing season. In fact, nearly every tree species has one or more species of aphids infesting its leaves. The aphids may occur in the winged or wingless forms. They suck the sap through their long pointed beaks and excrete a sticky sub- stance called "honey dew," which drips upon the foliage, giving the leaves a varnished appearance. In the honey dew a black fungus or sooty mold grows, giving the leaves a blackened appear- ance. Ants feed upon the honey dew and are usually present on INSECT PESTS OF NURSERY STOCK I5I aphid-infested trees, but the ants do no harm to the trees. The presence of aphids may be noticed also in some cases by the curled leaves or the abnormal dropping of the leaves. Aphids may be killed by spraying with a contact spray like nico- tine solution and soap, but they must be hit by it. As they are mostly on the under leaf surface, the spray should be directed there. Applications should also be made before the aphids are de- structively abundant and before the leaves are curled or seriously injured. Beech Woolly Aphid (PJiyllapJiis fagi Linn.) Trees of the European beech, Fagus sylvatica, especially the pur- ple-leaved form, are usually infested in Connecticut by a white woolly aphid which appears on the under side of the leaves in early summer. The woolly appearance is due to slender wax fila- ments secreted by the aphids. They may be controlled like other aphids with a spray of nico- tine solution and soap. Willow Aphids Large reddish brown aphids are often present in large num- bers on the twigs of willows, where they lay eggs late in the sea- son. These belong to the genus Chaiiophorus, two species — vim- inalis Monell and nigrae Oest. — occurring in Connecticut. There is also an even larger species, Longistigma caryae Harris, which occurs on oak, hickory, maple, elm, poplar, linden, and sycamore. The remedy is that given above. Oak Gall Scale (Kermes sps.) Hard, globular scales occur on oak trees in nurseries and are usually gray or brown in color. There are several species, some smooth and shiny, some dull, and some pubescent. The partially grown females winter in the crevices of the bark, and some spe- cies in the spring go to the leaves. The young appear in Juh' or August. The bodies of the females often remain on the twigs for nearly a year after they die. Shown on Plate XV, e. Spraying the dormant trees in early spring with a miscible oil (i - 15) is effectu-e. Pit-Making Oak Scale (Asterolccanium variolosiim Ratz.) This scale infests several species of oak but is most frequently encountered on English or golden oak, Ouercus robur. It has a 152 CONNECTICUT EXPERIMENT STATION BULLETIN 292 smooth, glassy, convex shell about one-sixteenth of an inch in diameter and is of a beautiful greenish-golden color. A little pit is formed around each insect, from whence its common name arises. It is also called the golden oak scale. It is believed to be single-brooded, but this point has not been determined for Con- necticut. The insect passes the winter in the egg-stage under the old shells, and the young appear in May and June. The in- sect is shown on Plate XI, c. A dormant spray of a miscible oil (i - 15) is probably the best means of control. (Ohio Bulletin 332, page 306). Tulip Tree Scale {Tourney ella liriodendri Gmel.) This is our largest soft scale, the females being brown, hemi- spherical, and nearly one-third of an inch in diameter, shown in I Fig. 28. Tulip tree scale. Fig. 28, and on Plate XI, d. The males are oval, gray, and flat- tened, and about an eighth of an inch in length. The scales usu- ally occur on the lower branches of the tulip tree, and there is a single generation each year, the young appearing in September. The remedy is to spray as soon as the leaves fall, using a miscible oil or a nicotine solution. (Report for 1921, page 176). Terrapin Scale (Lecanium nigrofasciafum Pergande) This is a small, oval, and very convex soft scale, reddish-brown in color, which infests the small twigs of maple trees (see Plate XI, b), especially the red and silver maples. On large trees it is more apt to be on the lower branches, and though not particularly a nursery pest, it is occasionally found on the nursery trees of larger size. The eggs are formed under the old shells in June and hatch late in June or early in July. Only the females live through INSECT PESTS OF NURSERY STOCK 153 the winter, and they are in a partially grown state. The scales suck the sap from the twigs in fall and spring, becoming mature about June i. The remedies are contact insecticides, especially miscible oils ( I - 15), applied when the trees are donnant. (Report for 1921, page 183). European Fruit Lecanium. See page 123 European Elm Scale (Gossyparia spuria Mod.) This is a chocolate-brown scale, oval in shape, with a fringe of white wax around the margin, shown on Plate XI, a. It usually occurs in the crevices of the bark of trunk and larger branches. There is one generation each year, the insect hibernating on the bark in a partially grown state. The young appear in June. The standard contact sprays will kill this scale at almost any time of the year, though more thorough applications can be made when the trees are dormant. (Report for 1905, page 235). Cottony Maple Scale (Ptdvinaria vitis Linn.) This insect is perhaps the most conspicuous of all the scale insects on account of the abundant secretion of wax surround- ing the eggs. During the winter it occurs on the bark and resem- bles any other large, brown, soft scale, but about the time the trees begin to grow, the posterior end of the insect becomes raised, and the egg-sac begins to protrude, as shown on Plate XI, e. When fully developed it is as long as the insect itself and resembles a tuft of cotton. Each female deposits about three thousand eggs, which hatch in late June or early July. The young at first go to the leaves and establish themselves mostly on the under side along the midrib and veins. Before the foliage drops, they return to the twigs and settle on the bark for the winter. In Connecticut this insect has occurred abundantly only in the vicinity of Stamford and attacks silver and red maples, though all other kinds are also infested in some portions of the Middle West, where there are periodical outbreaks every eight or ten years. It occurs in Connecticut nurseries on a variety of trees, shrubs, and vines, but is seldom sufficiently abundant to cause injury. It is perhaps the most common on maple. The remedy is to spray the dormant trees in early spring, using one of the miscible oils (i - 15). (Report for 1921, page 179). 154 CONNECTICUT EXPIiiaMliNT STATION BULLETIN 292 Elm Scurfy Scale (Chionaspis avwricana Johnson) This scale, which occurs on the twigs and branches of ehn. is dirty-white or gray in color and somewhat resembles the oyster- shell scale. It passes the winter in the form of purplish eggs under the old shells, and there are two generations each season. Small branches are killed in severe infestations, and the general vitality of the tree is lowered. Spraying the dormant trees with liquid lime-sulphur (i -8) or with one of the miscible oils (i - 15) will control this insect. (Ohio Bulletin 332, page 290). Oyster-Shell Scale. See page 123 INSECTS INJURING SHRUBS AND VINES Key A. Feeding upon the leaves : 1. Conspicuous caterpillars, bearing horns or spines 2 Conspicuous caterpillars, without distinct horns or spines 4 2. Caterpillars with horns or fleshy protuberances 3 Caterpillars 2-3 inches long, covered with branched stinging spines, pale green with reddish band along each side, lo Caterpillar, p. 155 Caterpillars one inch long or less, each end with a pair of promi- nent tubercles bearing stinging spines ; color brown with green saddle Saddle-back Caterpillar, p. 155 3. Green caterpillars with single horn on tail, on grape or Virginia creeper Sphinx Caterpillars or Horn Worms, p. 156 Brown caterpillars with fleshy protuberances on each side of tho- racic segments, on Dutchman's pipe vine, Pipe-Vine Caterpillar, p. 156 4. Large fleshy caterpillars. 3-4 inches long, bluish-green, with promi- nent tubercles, usually feeding on rosaceous plants, Cecropia Caterpillar, p. 156 Smaller (1-2 inches), finely cross-striped with black, white and orange, feeding upon Virginia creeper. Eight-spotted Forester, p. 157 5. Small, green, slug-like caterpillars on rose.... Rose Sawflies, p. 157 Larger, gray, slug-like caterpillars on Lonicera, Honeysuckle Sawflies, p. 158 B. Borers in stems : 6. White grub, about one inch long, tunneling in lilac or privet, Lilac Borer, p. 158 Very small, flat-headed white grub, forming swellings on rose stems Rose Stem Girdler, p. 158 C. Forming galls on leaves : 7. Shiny, semi-transparent galls on leaves and tendrils of grape, Grape-vine Tomato Gall, p. 158 Small pocket galls on leaves Eriophyid Mites, p. 159 INSECT PF.STS OF NURSERY STOCK 155 D. Sucking sap from leaves or bark : 8. Scale insects protected by shells, mostly on bark 9 Green plant lice on leaves Aphids, p. 150 9. Female scale, circular or nearly so 10 Female scale, pear-shaped, dark gray, on Euonymus, Euonymus Scale, p. 159 10. Female scales, 2-3 mm., snow-white, exuviae marginal, light yel- low, eggs purple, on rose and blackberry Rose Scale, p. iS9 Same size, scale whitish but more or less covered with bark of host, exuviae marginal, orange-yellow ; on cherry, privet, and Catalpa bungei White Peach Scale, p. 159 Female scales less than 2 mm., dark gray, exuviae central, yellow, San Jose Scale, p. 137 lo Caterpillar {Antomcris io Fabr.) This caterpillar is from two to three inches long when fully grown, pale green, with a reddish and white stripe along each side, each segment bearing a number of tubercles arranged crosswise in a row, as shown on Plate XII, c. Each tubercle has a number of spreading, stinging spines which cause an intense itching or rash on coming in contact with the human skin. Apparently there is only one generation each year, and the insect passes the winter in its cocoon among the leaves on the ground. The moths emerge in June and July. The female has a wing-spread of about three inches, and the male about two and one-half inches. The ground color is yellow with reddish markings, and in the female the entire fore wings are tawny. On each rear wing in both sexes there is a bluish eye spot margined with black, and with a white dash in the center ; between the spot and the wing-margin are two con- centric rings, one red and the other black. The caterpillar feeds upon many kinds of shrubs and trees. Spraying with lead arsenate is the remedy. (Ohio Bulletin 332, page 270). Saddle-Back Caterpillar {Sihine sfiniulea S. & A.) The caterpillars of this species are often gregarious and feed upon a large number of plants. They are nearly an inch long, without true legs, and are brown and green in color. Both ends of the body and the long tubercles are brown, but the middle of the body looks as though covered by a bright green blanket with an oval opening on the back, as shown on Plate XII, a. This gives it the common name "saddle-back." On the prominent brown tubercles, and laterally on the smaller green ones, there are branched, stinging spines which to the touch are quite painful for an hour or two. The reddish-brown moth has a wing-spread of about one and one-half inches. There is one generation annually. Spraying with lead arsenate will prevent defoliation. (Report for 1914, page 188). 156 connecticut experiment station bulletin 292 Sphinx Caterpillars or Horn Worms Grape vines, Virginia creeper, and Boston ivy are often eaten by caterpillars of this group. Most of them may be distinguished by the sharp horn on the back near the tail, as shown in Fig. 29, and several species belonging to different genera may be encoun- tered. All belong to the family Sphingidae. The abbot sphinx, Sphecodina abbolti Swains., has in place of the horn a shiny spot or tubercle. This caterpillar is brown, veined Fig. 29. A sphinx caterpillar or horn worm. with a darker brown, but a form occurs having a large green patch on the dorsal portion of each segment. All sphinx moths have large bodies and long narrow wings. They fly at dusk, poise with vibrating wings before deep-throated flow- ers, and for this reason are called "humming-bird moths." Hand picking is the usual remedy, but if the caterpillars are in- juriously abundant in nursery or vineyard, spraying with lead ar- senate will prevent defoliation of the vines. Pipe- Vine Caterpillar {Papilio philenor Linn.) Wherever the Dutchman's pipe, Aristolochia sipho, is grown, the leaves may be eaten by the pipe-vine caterpillar. This caterpillar is velvety dark brown or black, marked with orange spots and bearing a number of long black and orange protuberances, and is shown with cocoon on Plate XII, d. When fully grown it is two inches or more in length. The adult is a swallow-tail butterfly having a wing-spread of 3-3.5 inches, velvety black with metallic bluish or greenish reflections. There are two generations each year. Spraying the vines with lead arsenate is probably the best rem- edy. (Holland's Butterfly Book, page 315). Cecropia Caterpillar (Samia cecropia Linn.) This is one of the largest caterpillars commonly found feeding upon nursery stock and is from 3-4 inches long when full grown INSECT PESTS OF NURSERY STOCK 157 and about three-fourths of an inch thick. It has a pecuhar bluish- green color with a cross row of tubercles on each segment; those on the second, third and fourth segments are red, the other dorsal ones yellow, with pale blue tubercles along the sides near the breathing pores. (Shown on Plate XII, e). The cocoon is brown and fastened lengthwise to a twig. The moth has a wing-spread, of 4-6 inches, is gray and prettily marked with black, red, and creamy-white, with a lunule on each wing. There is only one generation each year, and it passes the winter in the cocoon. The caterpillar feeds upon spiraea and other plants of the rose family, but is also found upon box-elder and willow. Hand-picking is perhaps the only remedy needed in Connecticut, but where abundant, the caterpillars may be controlled by spray- ing with lead arsenate. (Ohio Bulletin 332, page 266). Eight-Spotted Forester {Alypia octomaculata Fabr.) The caterpillars of this insect occasionally defoliate Virginia creeper and also feed upon grape, barberry, and rose. They feed in July, and are between one and two inches in length. Their general color is brown with a bluish tinge. Each segment is nar- rowly banded crosswise with black and white, with a broader band of orange dotted with small black dots. Head and cervical shield are orange with black dots. The moth is black with two round yellow spots on each fore wing and two smaller white spots on each rear wing. The insect passes the winter in the chrysalid stage in the soil, and there is only one annual generation. Caterpillars and moths are shown on Plate XII, b. Hand-picking and spraying with lead arsenate are the remedies. (Report for 1916, page 118). Rose Sawflies {Caliroa aethiops Fabr. and others) Small, greenish slugs often feed upon rose leaves, skeletonizing them. Several species may be involved, one of the most common being named above. This has only one annual generation, but some of the other species probably have more. The adults are four-winged flies, and on account of the toothed ovipositor in the female they are called sawflies. The larvae or slugs are easily killed by spraying with lead ar- senate, with nicotine solution and soap, or fresh hellebore applied as a spray or dust. (U. S. Farmers' Bulletin 1252). 158 CONNECTICUT EXPERIMENr STATION BULLETIN 292 Honeysuckle Sawflies (Abia americana Cress., and A. inflata Nort.) The leaves of various species of bush and dimbing honeysuckles are sometimes eaten by the larvae of at least the two species of sawflies named above. In one case the climbing honeysuckle on a wire fence was defoliated. The larvae were grayish-green with orange spots, and presumably there is only one generation each year. Defoliation may be prevented by spraying with lead arsenate. '• Lilac Borer (Podosesia syringae Harris) Lilac and privet are often injured by white grubs burrowing in the stems. Sometimes the stems break over, and in other cases they remain standing and present an unthrifty appearance. The adult is a wasp-like, clear-wing moth of the family Sesiidae, and there is one generation each year. (See Plate XIH, a). The best means of control is to cut out and burn the infested stems. (Report for 1905, page 260). Rose Stem Girdler (Agrilus viridus var. fagi Ratz.) Recently an European insect has appeared in Connecticut, called the rose stem girdler, which causes the formation of swellings on the stems of various species and varieties of rose, as shown on Plate XHI, b. Rosa rugosa and R. hugonis have been noticed with- these swellings, which are the result of the plant making an at- tempt to heal the wounds around the galleries of the larvae. The adult is a metalHc, coppery beetle, about one-third of an inch long, which lays eggs singly on the bark in June and July. The larva is a slender white, flat-headed grub. The only known remedy is to cut and burn the infested stems in winter or early spring before the beetles emerge. (Report for 1925, page 325). Grape-vine Tomato Gall (Lasioptera vitis O.S.) The leaves, peduncles, tendrils, and tender shoots of grape vines are often marked and seriously distorted by irregular water thickenings or swellings which are sometimes red and sometimes green, as shown on Plate XV, b. The adult is a two-winged fly~ which places its eggs on or in the succulent tissues. The larvae develop in cells in the center of the galls. The only known method of control is to clip off and burn the infested tips. (Report for 19 16, page 146). INSECT PESTS OF XURSERY STOCK I 59 Eriophyid Mites (Family Eriophyidae) The leaves of shrubs and young trees often exhibit minute galls, usually on the upper surface, caused by mites of the family Erio- phyidae. A common form makes elongated pocket galls on the pearl bush, Exochorda grandiflora. Other forms are found on elder, birch, maple, and elm. These mites do not seriously affect the vitality of the host but render its appearance unsightly. (Shown on Plate XV, d). Probably the best control is a dormant spray of liquid lime- sulphur in early spring just before the leaves appear. Aphids (Family Aphididae). See page 150 EuoNYMus Scale (Chionaspis cuonymi Comst.) Some kinds of Euonymus, as well as bitter-sweet, are infested and seriously injured, even sometimes killed, by this scale. The females are pear-shaped, dark gray, and occur on leaves or tender shoots. The males are smaller, elongate, with parallel margins, and are snowy white. There are said to be two broods each year, the insect passing the winter as eggs under the shells of the mother » scale. This scale is shown on Plate XV, a. {' The remedies are to prune off and burn the worst-infested !■ stems. The remaining portions may then be sprayed in early April !{{ with a miscible oil (i - 15), or in summer with kerosene emulsion J- containing 15 per cent or more of kerosene. J)| (Report for 1921, page 185). ;; Rose Scale (Aulacaspis rosae Bouche) j\ Rose, blackberry, and some other plants are often infested by ^ a whitish scale, nearly circular, and a little less than one-eighth of an inch in diameter. These are the female scales which, during ' the winter, cover purple eggs. The male is long and narrow, with ■ three ridges lengthwise, and is also white. This scale is shown j on Plate XIV, a. Cutting and burning the worst-infested stems is recommended; then spray while the plants are dormant, using either liquid lime- sulphur (1-9) or a miscible oil (i - 15). (Ohio Bulletin 332, page 295). ! White Peach Scale (Aulacaspis pentagona Targ.-Tozz.) This has also been called the West Indian peach scale, and though closely related to the rose scale, is much less conspicuous on account of the bark, dirt, and extraneous matter on the shells. l6o CONNECTICUT EXPERIMENT STATION BULLETIN 292 In Connecticut it has been found on cherry, privet, and Catalpa Bungei, but is not beheved to be an important or serious pest. It is shown on Plate XIV, b. Spraying with a miscible oil or with lime-sulphur when the plants are dormant is believed to be an effective means of control. (Report for 1913, page 240). San Josfe Scale. See page 137 INSECT PESTS OF EVERGREEN TREES AND SHRUBS Key A. Chewing insects devouring leaves and buds : 1. Larvae devouring the leaves 2 Larvae mining v^rithin the leaves 3 2. Larvae an inch or more in length, w^hite, buff, or green, dotted, striped or mottled with brown or black, feeding gregariously, without webs, on pines Pine Sawflies, p. 161 Larvae one-half inch long, striped lengthwise with light and dark brown, webbing together the twigs of juniper, Juniper Webworm, p. 161 3. Minute larvae mining within the leaves of arborvitae, Arborvitae Leaf-Miner, p. 161 Maggots mining within the leaves of box. Boxwood Leaf-Miner, p. 162 4. Destroying the terminal buds of pine, causing crooked growth, European Pine Shoot Moth, p. 162 Destroying the terminal buds of spruce Spruce Budworm, p. 162 B. Attacking roots or stems : 5. Gnawing the bark of the stems of coniferous seedlings, Pales Weevil, p. 163 Gnawing the bark of the roots of hemlock and Taxus, Otiorhynchid Weevils, p. 163 Eating off the roots of seedlings White Grubs, p. 164 6. Boring in the leaders of white pine, causing them to wilt in July, White Pine Weevil, p. 164 Boring in the stems of rhododendron. Rhododendron Borer, p. 165 C. Sucking juices from leaves or bark: 7. Woolly aphids : wax secretion prominent 8 Wax secretion slight, forming cone-shaped galls on spruce, Spruce Gall Aphids, p. 165 8. Cotton-like tufts of wax in axils of leaves and white patches on bark of white pine Pine Bark Aphid, p. 166 Cottony wax secretion on leaves of larch, Larch Woolly Aphid, p. 166 Cottony wax secretion on leaves of Douglas fir, Douglas-Fir Woolly Aphid, p. 166 9. Elongated white scales on pine leaves Pine Leaf Scale, p. 166 Circular scales on leaves of juniper Juniper Scale, p. 167 10. Lace-like insects on under side of leaves of rhododendron and Kalviia Rhododendron Lace Bug, p. 167 Red spiders on leaves Spruce Mite, p. 167 INSECT PESTS OF NURSERY STOCK l6l Pine Sawflies (Family Tenthredinidae) Different kinds of pine trees are sometimes defoliated by sawfly larvae which usually feed gregariously and are whitish, greenish, or buff, variously dotted or otherwise marked with black or brown. They have the habit of coiling the tail around a leaf as a means of holding on to the food plant. One of the commonest species in nurseries is the imported pine sawfly, Diprion simile Hartig. The larvae are slightly more than an inch long, greenish yellow, more or less striped dorsally with brown, and the sides curiously spot- ted and reticulated, as shown on Plate XIV, c. This species feeds upon the white, Bhotan, Scotch, Austrian, Korean, Mugho, and several other kinds of pines, and there are two full generations each season. Some of the brown cocoons are fastened to the twigs and some are placed upon the ground under the trees. Other spe- cies feeding on pine in Connecticut are: Neodiprion lecontei Fitch, on white, jack, red, Scotch, Austrian, and Mugho pines; N. pinetum Norton, on white pine, and N. pimis-rigidae Norton, on pitch pine. The remedy is to spray with lead arsenate. (Report for 1915, page 118). Juniper Webworm (Dichomeris marginellus Fabr.) Juniper twigs are webbed together by the larvae of this insect, which feeds upon the leaves inside the nest. (See Plate XIV, d). Low juniper in ornamental plantings is often defoliated, but ap- parently Juniperus hihernica is greatly preferred. The caterpil- lars are about half an inch long, light brown, with longitudinal stripes of darker brown. The adult is a moth with a wing-spread of 15 mm., dark brown, with white front and rear margins on the fore-wings. The larvae pupate in the webs, and the moths appear early in June, but the life history has not been carefully worked out, and it is possible that there is more than one generation each year. Spraying heavily with lead arsenate is a satisfactory remedy. (Report for 191 5, page 137). Arborvitae Leaf-Miner {Argyresthia thuiella Pack.) Small larvae mining in the leaves often give a brown or dead appearance to arborvitae. (See Plate XVI, b). The adult is a tiny moth which lays eggs on the leaves in June. There is one annual generation, and the insect spends the winter in the cocoon in the mine. Though remedial measures are of somewhat questionable value, it is thought that a heavy application of nicotine solution and soap or of fish-oil emulsion may kill some of the eggs or larvae and thus prevent severe injury to the foliage by the insects. (Report for 1921, page 157). l62 CONNECTICUT EXPERIMENT STATION BULLETIN 292 Boxwood Leaf Miner (M onarthropalpus buxi Labou) The adult of this insect is a yellow midge or two-winged fly which lays eggs in the leaves in May, and the maggots feed and develop between the upper and lower epidermal layers, causing a blistering and distortion of the leaves, often called galls. (Shown on Plate XVI, a). The foliage is usually thin on infested plants. The maggots live over winter in the leaves and pupate in spring. The remedy is to spray the plants with a cheap molasses, one part in four parts of water, with the addition of nicotine sulphate, one part in 500 parts of the spray material. The first application should be made when the adults first begin to emerge from the infested leaves, and the plants should be kept covered for three weeks. One application each week will answer in fair weather, but the plants should be sprayed after each rain. (Report for 1923, page 312; Maryland Bulletin 272). European Pine Shoot Moth (Rhyacionia (Evetria) hiioliana Schiff.) This is a serious pest of all kinds of pines in Europe and is now present in Fairfield County, Connecticut, where it seems to prefer the red pine. The adult is a small orange moth which in August lays eggs singly on the newly formed terminal buds which are ready for next year's growth. The young larvae soon eat their way into the buds and excavate cells in which they spend the win- ter. The following spring the larva leaves its winter home and bores into the next bud, and thus destroys as many buds as may be needed for food. It also attacks the young shoots, feeding on one side, causing them to become curved and deformed. When ma- ture, the larva pupates in an excavated shoot, and three weeks later the moth emerges. Apparently there is only one generation each year. Distorted and crooked growth called "bayonet shoots" follows the attack of this insect. No remedy is known other than to prune and burn the infested buds and shoots. (U. S. D. A. Bulletin 170). Spruce Budworim {Harmologa fumiferana Clem.) Spruce and balsam trees are often severely injured by this in- sect. The moths emerge in June and July and the females lay upon the needles their eggs, which hatch in ten days, but the larvae do little or no feeding until the following spring. They pass the winter in protective cases which they spin in crevices on the tree or 'Other convenient shelters. The young caterpillars feed for about three weeks in the spring at the base of needles upon the terminal shoots, moving about freely. The severed needles are INSECT PESTS OF NURSERY STOCK 163 loosely attached to the twigs by the silk threads spun by the larvae. When fully grown each larva is about three-fourths of an inch long, and it then pupates upon the tree. The adult moth is gray with brown markings and white spots. There is only one annual generation. Spraying heavily with lead arsenate will doubtless prove effec- tive in the nursery and on small ornamental trees. (Manual of Tree and Shrub Insects, page 285). Pales Weevil (Hylobiits pales Herbst) This insect is a Curculionid or snout beetle less than half an inch in length. In color it varies from dark reddish-brown to black, and usually has gray or whitish hairs so arranged as to form small spots on the wing-covers. This beetle is believed to be responsible for the failure of much of the forest planting where conifers are used and has also injured seedlings in nurseries by eating off the bark of the stems, thus in effect girdling the young trees. Nearly all kinds of coniferous trees are attacked, and the feeding is done at night. There is only one generation each year, and the beetles hibernate in the soil at the base of the trees. The eggs are laid and the larvae feed in pine stumps and logs. As a control measure, seedlings or nursery stock should not be grown in close proximity to pine logs, stumps, or lumber. (Harvard Forest Bulletin 3). Otiorhynchid Weevils {Otiorhynchus sulcatus Fabr. and 0. ovatus Linn.) Ta.vus plants are occasionally injured in nurseries by the grubs or larvae of Otiorhynchus sulcatus Fabr., a black snout beetle with faint gray spots, half an inch in length, commonly called the black vine weevil, and shown on Plate XVIII, b. A case of injury occurred in a nursery in 1913: The smaller roots had been devoured, and the larger ones and the main stem had been girdled. In 1909, hemlock trees from 12 to 18 inches tall showed signs of unthriftmess, failed to grow, and some of them dropped their leaves. At the roots were grubs, pupae, and adults of Otiorhynchus ovatus, commonly known as the strawberry crown girdler. This species is about one-fourth of an inch long and is brown without color markings. This smaller species had girdled the main stem and larger roots. Treating the soil with an emulsion of carbon disulphide, as is done to kill the grubs of the Japanese beetle and the Asiatic beetle, may be recommended in severe infestations. (Report for 1909, page 370; 191 3. page 230). 1 64 CONNECTICUT EXPERIMENT STATION BULLETIN 292 White Grubs {Phyllophaga or Lachnosterna sps.) The larvae of May or June beetles occasionally eat off the roots of coniferous trees in nurseries. There are probably several spe- cies involved, and most of them require three years to complete the life cycle. The injury is usually the most severe the third sea- son, when the grubs are large and voracious. Shown in Figs. 30 and 31. In some cases it may be possible to treat the soil about the plants with an emulsion of carbon disulphide. (Report for 1912, page 288). Fig. 30. White grub and its adult, the common June beetle. Fig. 31. Pine seedling with roots eaten off by white grubs. White Pine Weevil (Pissodes strobi Peck) The white pine weevil probably causes more injury to white pine trees in Connecticut than any other insect, and perhaps more than all other insects together. It also injures spruce trees. There is one annual generation, and the beetles hibernate somewhere dur- ing the winter and appear on the pine trees about May i. They make punctures in the bark of the leaders or terminal, shoots of the preceding season's growth. In some of these punctures eggs are laid and soon hatch. The grubs feed in the cambium and sometimes in the pith, becoming mature in about six weeks, when they excavate cells in the wood in which they pupate. Late in July and continuing until September, the adult beetles emerge. The infested leaders wilt in July and later turn brown and die. In time a lateral branch will grow upright and take the place of INSECT PESTS OF NURSERY STOCK 165 the leader, but this makes crooked and ill-shaped trees. The injury caused by this insect is shown in Fig. 32 and on Plate XVIII, c. Trees may be partially protected by spraying the leaders about May I with either lead arsenate or liquid lime-sulphur (i -9). (Report for 1919, page 144). Fig. 32. Pupal cases, larval cells, and exit holes of the white pine weevil. About twice natural size. Rhododendron Borer (Sesia rhododendri Beut.) Serious injury to rhododendrons in ornamental plantings has been caused by the rhododendron borer in Connecticut, though the work of the insect has not been very noticeable in nurseries. The adult is a wasp-like clear-wing moth v/hich lays eggs in late May or June on the twigs. The larva soon after hatching tunnels into the sapwood of the stem, where it forms irregular galleries from j! one to two inches long, usually just below a crotch. Larvae are j- yellowish- white, about half an inch long, and usually become full ]■, grown by October but remain in their galleries through the winter •'' and pupate there in the spring. Two weeks later the moths ap- > pear, and there is only one annual generation. !: The injured stems cannot supply the necessary moisture and the jil leaves turn brown and die. The stems are often broken at the jil point of injury. Rhododendron maximum is perhaps more se- ;J| verely injured than other species, but hybrid rhododendrons are !j also attacked. The injury is shown on Plate XVII, a. i There is no remedy except to cut out the borers and to prune i off and burn infested stems and branches. ; (Report for 1922, page 347). i i Spruce Gall Aphids {Adelges, Chermes, sps.) One of the commonest pests in nurseries is the spruce gall aphid, Adelges abietis Linn., which forms cone-shaped galls at the base of the new growth on Norway spruce, and sometimes black, red, and white spruce trees are infested to a less extent. There are two broods each season, the winter being passed by the immature females on the twigs. They reach maturity and lay on the leaves masses of eggs which hatch soon after the new shoots appear in May. The young aphids crawl to the base of the shoots and at- l66 CONNliCTICUT EXPliRIMENT STATION BULLETIN 292 tach themselves where the irritation resulting from their feeding causes the needles to swell at the base until they touch each other. Thus pockets are formed in which the young aphids are enclosed, and the result is one continuous gall, shaped like the cone of the tree. These galls break open in August, and the aphids go to the leaves and soon transform to mature females which lay eggs for the second brood. One of the galls is shown on Plate XVII, c. Larger terminal galls on the Colorado blue spruce are formed by Gillettea cooleyi Gill., (see Plate XVII, b), and a form known as variety cozveni Gill, is the woolly aphid common upon the leaves of Douglas fir. Another species, Adelges (Chermes) strobilobius, is known as the larch woolly aphid, and is common on larch foli- age in midsummer. The remedy is to spray the trees early in April with a miscible oil (i - 25), to kill the overwintering females. The summer forms on leaves may be killed by spraying with nicotine solution and soap. (Report for 1926, page 223). Pine Bark Aphid [Adelges (Chermes) pinicorticis Fitch] Small, cotton-like tufts of wax in the axils of the leaf clusters are common on small white pine trees, and on larger ones large white patches on the bark are often seen. The pine bark aphid is the cause, but its life history is not fully known. Eggs hatch about May I, and the young settle along the twigs and suck the sap from the bark, soon becoming covered with slender filaments of wax, giving them the appearance of small tufts of cotton, as shown on Plate XVIII, a. Trees can be entirely cleared of this insect by a thorough spray- ing in June with kerosene emulsion, and probably nicotine solu- tion and soap will prove equally effective. (Report for 1919, page 155). Pine Leaf Scale (Chionaspis pinifoliae Fitch) Often small pine trees show elongated white scales on the leaves. This is the pine leaf scale which infests Mugho, Austrian, jack, red, Scotch, stone, and white pines, sometimes killing them. There are two generations each year, and purple eggs under the female shells carry the species through the winter. These eggs begin to hatch in May, but the hatching period is a long one, and the two broods are not distinct but overlap. Illustrations of this scale are shown on Plate XV, c. Control measures for this insect have not been given a thorough trial in Connecticut, but it can doubtless be held in check bv dor- INSECT PESTS OF NURSERY STOCK 167. mant spray applications of liquid lime-sulphur (i -9), or of mis- cible oil (i - 15) in April, and of nicotine solution and soap be- tween June I and August i. (Report for 1921, page 181). Juniper Scale {Diaspis carueli Targ.-Tozz.) Small, circular, whitish scales 1-2 mm. in diameter are often present and sometimes very abundant on the leaves of juniper, resulting in a yellow and sickly appearance. Spraying with a miscible oil (1-25) in spring, before the new growth starts, will probably control this insect. (Report for 1920, page 212). Rhododendron Lace Bug (Leptobyrsa rlwdodendri Horvath) This is a sucking bug belonging to the family Tingidae and com- monly called lace bug. It is on the under side of the leaves of rho- dodendron, especially R. maxima, and Kalmia latifoUa or moun- tain laurel. Apparently there is only one brood each year. The eggs are laid along the midrib, and there is much brownish dis- coloration from the excrement. The injured leaves show whitish spots on the upper surface. (See Plate XX, d). Spraying the under sides of the leaves with nicotine solution and soap when the bugs are present has been efitective. (Report for 1921, page 200). Spruce Mite (ParatetranycJius ununguis Jacobi) Spruce trees and other evergreens are often severely injured by Inites. Such injury is noticed somewhere in the State each year, though it is usually more severe and more widespread in seasons of drought. The leaves are peppered with small whitish spots, covered with brownish eggs and egg-shells, and are usually more or less webbed together. The greenish-yellow living mites and their cast skins are also abundant. Spraying in spring before the new growth starts with a mis- cible oil (1-15) to kill the eggs, and the application of liquid lime-sulphur (1-50) or linseed oil emulsion to kill the mites in midsummer, are recommended. Some of the oil preparations are apt to remove the bloom from some of the varieties of blue spruce. (Report for 1922, page 340). l68 CONNECTICUT EXPERIMENT STATION BULLETIN 292 INSECTS INJURING PERENNIAL PLANTS Key Chewing Insects : 1. Attacking the leaves 2 Attacking the stem or root 5 2. Devouring the leaves 3 Mining vi^ithin the leaves of columbine, Columbine Leaf-Miner, p. 168 3. Perforating or devouring portions of the entire thickness of the leaves 4 Minute jumping insects feeding on surface of leaves of seedlings, Garden Spring-Tail, p. 169 4. Feeding at night, hiding during the day: Larvae with true legs, curled up in soil around base of plant. Climbing Cutworms, p. 130 Gray or brown slugs without legs, hiding under rubbish and leav- ing a slimy trail Garden Slugs, p. 170 5. Cutting off the stem near the surface of the ground: Larvae curled up in soil near the plant Cutworms, p. 169 Striped larva boring lengthwise in stem Stalk Borer, p. 170 Pink larva burrowing in rootstocks of iris.. Iris Root Borer, p. 171 Sucking Insects : 6. Visible insects attacking leaves or shoots at tip 7 Reddish mites with eggs and shells injuring leaf surface, Red Spider, p. 150 Microscopic, glassy mites, curling leaves of larkspur and some other plants Cyclamen Mite, p. 172 7. Exceedingly active flying bugs, with nymphs on leaves 8 Rather inactive plant-lice on leaves or stems Aphids, p. 150 8. Greenish-yellow bugs ; adult with four black stripes, on terminal leaves Four-lined Plant Bug, p. 172 Grayish or brownish bugs on terminal leaves, Tarnished Plant Bug, p. 139 Columbine Leaf-Miner {Phytomyza aquilegiae Hardy) In June, whitish serpentine mines begin to appear in the lower leaves of columbine. There are often several miners in a leaf, and the mines may continue to increase in size until the entire leaf is involved. Later the small leaves around the flower stalks are infested. There are several generations, the winter being passed as pupae in the ground. The eggs are laid in the under sides of the leaves and hatch in less than a week. The larvae mine between the upper and lower epidermal layers of the leaf, becoming mature in about two weeks, and emerge from the mines through crescent-shaped openings. They attach themselves to the leaf and pupate. In two weeks the adults emerge. They are small, dark brown flies about 2 mm, long. Injured leaves are shown on Plate XX, a. INSECT PESTS OF NURSERY STOCK 169 Cultivating the ground around the plants in late fall or early spring will reduce the infestation. Removing and destroying the mined leaves when the infestation first appears will aid in the con- trol of this pest. (Report for 1894, page 145 ; New Jersey Department of Agri- culture, Circular 36, page 13). Garden Spring-Tail (Sminthurus hortensis Fitch) Small seedling plants, particularly in hotbeds or cold frames, are often injured in early spring by minute, purplish, jumping insects which eat off the surface tissue from the leaves. These tiny in- sects are purple, spotted with yellow, and jump like fleas. Each has a globular-shaped body and rather large head with narrow neck. A forked tail-like appendage used in jumping extends rear- ward from the under side of the body, as shown in Fig. 33. Fig. S3- Garden spring-tail. Fig. 34. Cutworm and characteristic injury to plant. This insect may be controlled by spraying or dusting the plants with nicotine. (Bulletin 6, Tobacco Experiment Station, page 86 T). Cutworms (Noctuidae, several species) Perennial plants, especially the seedlings and tender shoots, are often cut off near the ground by cutworms, as shown in Fig. 34. There are also other kinds of cutworms which climb and feed upon the leaves. Most of the cutworms are single-brooded and live through the winter as partially grown larvae. The adult moths emerge and lay their eggs in late summer. All cutworms are the larvae of rather inconspicuous gray or brown moths of the family Noctuidae, and there are perhaps a dozen or more species that are classed as cutworms. Injury from the climbing cutworms may be lessened by spraying the foliage with lead arsenate. The cutworms, which cut off the 170 CONNECTICUT EXPERIMENT STATION BULLETIN 292 stems of plants, can best be controlled with a poisoned bait distrib- uted about the field a few days before the injury becomes serious. A formula for this bait is as follows : Wheat bran 5 lbs. White arsenic or Paris Green 4 oz. Cheap molasses i pint Orange or lemon i fruit Water 7 pints Cut the fruit into small pieces and mix together to form a rather dry mash and scatter around the field. Garden Slugs (Family Limacidae) The leaves of garden plants are often eaten by slugs, which are closely related to snails but without the usual shell. One of the commonest species is the gray field slug, Agriolimax agrcstis Linn., and another and more striking species is the giant or spotted gar- den slug, Umax maximus Linn., shown in Fig. 35. Fig. 35. Spotted garden slug, natural size. (After Kingsley, Riverside Natural History). These animals feed at night on the tender leaves of garden and greenhouse plants, eating holes through the leaves or notches in the margins. They hide under rubbish during the day and leave a slimy trail wherever they crawl. Plants may be protected by spraying or dusting with lead arse- nate. As a rule, beds may be protected by surrounding them with a layer of air-slaked lime, but fine soot or coal ashes will answer the purpose, as the slugs do not like to crawl through such dry material. (Report for 1918, page 333). Stalk Borer {Papaipema nchris Guen.) The stalk borer may be found in any kind of herbaceous stem and attacks vegetables, annual and perennial flowering plants, and weeds. (See Fig. 36). Among the perennials it is often found in hollyhock, lily, larkspur, peony, and chrysanthemum. There is a single generation each year, and the insect passes the winter as an egg on the stem of dead grass. The eggs hatch in May and the INSECT PESTS OF NURSERY STOCK 171 larvae begin to tunnel in grass stems, later migrating to other plants. By August or early September, the larvae mature and pupate in the burrows ; a month later the adults emerge. The moth has a vi^ing-spread of about one and three-eighths inches and is brown, with conspicuous white discal spots on the fore wings. Larva and adult are shown on Plate XX, b and c. Heretofore the only remedy has been to cut out the borer, burn the infested stalks, or inject carbon disulphide into the burrow and plug the opening. Burning the grass and weeds around the fields Rl Fig. 36. Stalk borer. in late fall or early spring is now known to have a tendency to re- duce the number of stalk borers by killing the eggs. (Report for 19 19, page 180. New Hampshire Technical Bul- letin 34). Iris Root Borer (Macrouoctua onusta Grote) The rootstocks of iris plants are injured by a pink larva tunnel- ing in them, often devouring the entire rootstock and killing the plant. This is the larva of a brown moth with a wing-spread of about two inches, which probably has only one generation each year. The adults emerge in September or October and la}' eggs upon the iris leaves. These eggs hatch in spring, and the young borers find their way into the rootstock, where they feed and in- crease in size, becoming fully grown in August. They then pupate in the ground, and later the adults emerge. Larva and moth are shown on Plate XIX, b and c. Gathering and burning the leaves in late fall or early spring to destroy the eggs is the only remedy known. (Report for 1918, page 331). 1/2 CONNECTICUT EXPERIMENT STATION BULLETIN 292 Red Spider (Tetranychus bimaculatus Harv.) See page 150 Cyclamen Mite {Tarsonemus pallidus Banks) This mite often injures larkspur and several annual plants in the garden, as well as cyclamen, snapdragon, and chrysanthemum in the greenhouse. The new leaves become thickened and more or less curled, as shown on Plate XIX, a. Buds are also distorted and fail to open properly. The mites are almost too small to be seen by the naked eye, but under the magnifying glass they are white and glassy. Frequent and thorough spraying with nicotine solution and soap, one part in 500 parts of water, if started when the injury first appears, will control this pest. This treatment should be repeated each week and, in severe cases, twice each week. (Report for 1914, page 176). Aphids (Family Aphididae). See page 150 Fig. 2i7- Four-lined plant bug and injured currant leaf. Four-Lined Plant Bug (Poecilocapsus lineatus Fabr.) This greenish-yellow bug is about three-eighths of an inch long in the adult stage and has four black stripes on its back. In early spring when first hatched, it is bright red, with large black spots on the thorax. The eggs are laid by the adult bugs late in June or early July, but do not hatch until the following spring. The young nymphs feed for about three weeks and reach the adult or winged stage about the middle of June. There is but one gen- eration each year. This insect has a wide range of food plants, being particularly injurious to dahlia, rose, currant, gooseberry, and mint. INSECT PESTS OF NURSERY STOCK 1 73 It gets its nourisliment by sucking the juices from the tenderest leaves near the ends of the shoots. The injured leaves turn brown in spots, which later become transparent, and in heavy infesta- tions the entire leaf turns brown. (See Fig. 37). The adults are shy and very active when alarmed and very dif- ficult to capture. As they fly readily, they are not easily killed by sprays. The nymph, having no wings, may be killed by a spray of nicotine and soap, and some of the adults will hkewise be hit and killed. (Report for 1914, page 189). Tarnished Plant Bug {Lygus prate)isis Linn.) See page 139 PLATE I. '■^^■■j^^r^W^^f.. a. Adult female and egg-mass of fall cankerworm. Twice natural size. b. Egg-mass of fall cankerworm on t\,vig. Four times enlarged. __sd_ c. Apple leaf parth' devoured by cankerworms. d. Leopard moth larva in its burrow. Natural size. PLATE II. Nests of fall web-worni. (After Slingerland). c. White-marked tussock moth caterpillar. Natural size. b. Hickory tussock moth. Fully grown caterpillar on leaf. Natural .^ize. d. Gipsy moth caterpillar. Natural size. e. Gipsy moth egg-mass and pupa. Natural size. f. White-marked tussock moth. Nat- ural size. Female moth and egg-masses. PLATE III. igi5jS4?i&*«'^-G. a. Oyster-shell scale on poplar. Natural size. I). European fruit lecanium on blackberry. Natural size. c. Nest of tent caterpillar. d. Egg-mass of fent caterpillar on twig. Natural size. e. Tent caterpillars, partially grown. Natural size. PLATE IV. a. Apple and thorn skeletonizer ; apple leaf eaten by caterpillar, and cocoon. Somewhat reduced. b. Japanese beetle; adults twice enlarged. c. Rose leaves eaten by Japanese beetles. Natural size. PLATE V. fer- IK^ ^^m ^^^ HH^ ^0:fc%^ ^^j^mm »w^i ^^^^Hn r^^BV rriS Ifwfl I^^^H^^^H^kA IB :■<- ^ ■B ^^^^KS^: ""^^ ^ ->- \j Bj^v '-•■■- -''^^^ tri^^'^- ' .X Bl:. \ V. :^HM V^ 3^S# '*-' tUPIL ^ 1 P r a. Bircli leaf injund by the rose chafer. Xatural size. b. Peach twigs injured by larvae of the Oriental peach moth. Xatural size. PLATE VI. b. Yellow-necked caterpillars. Natural size. a. Red-humped caterpillar. Enlarged one and one-half times. c. Budded fruit trees, showing where buds were destroyed by climb- ing cutworms. Natural size. d. Peach borer in base of young tree. PLATE Vll. a. San Jose scale on peach twig. Twice natural size. b. Green aph:d= mm apple leaf. Natural size. c. Wooll:/ ari-.ids u;; f.vig;, showing galls and white flocculent ap- pearance. d. Eggs of European red mite. Ten times enlarged. Scurfy scale on currant; males at left: females at right. e. Leaf showing v^-ork of pear leaf blister mite. Xatural size. PLATE VIII. a. Leaves of gray birch injured by the imported birch leaf miner. b. Larvae of birch skeletonizer on leaf of gray birch. Slightly enlarged. PLATE IX. <^ 31^ a. Larvae and pupae of the larch sawfly. Natural size. b. Elm leaf licetle larvae and their work. Natural size. c. Larvae, pupa and adult of imported willow leaf beetle and injur}- to willow leaves. Slightly enlarged. PLATE X. a. Work of poplar and willow borer. Natural size. b. Linden borer, natural size, and its injury to }^oung linden trees, erreatlv reduced. PLATE XL a. European elm scale. Natural size. b. Terrapin scale. Xatural size. c. Pit-making oak scale. Natural size. d. Tulip tree scale. Natural size. e. Cotton}' maple scale. Natural size. PLATE XI!. b. Eight-spotted forester. Adults and larvae, natural size. a. Saddle-back caterpillar. Twice enlarged. c. lo caterpillars. Natural size. d. Pipe-vine caterpillar. Natural size. e. Cecropia caterpillar. Natural size. PLATE XIII. a. Lilac borer, showing adult pupa case and injured privet stem. Natural size. b. Galls of rose stem girdler, twice enlarged. PLATE XIV. a. Rose scale, twice enlarged. b. White puach scaiL, uvice enlarged. Imported pine sawfly larvae feed- ing on leaves. Natural size. d. Work of juniper webworm. PLATE XV. a. Euonymus scale, mostly males. A tew larger, gray females are present. b. Grape-vino tomato gall. c. Pine leaf scale, twice enlarged. e. Oak gall scale. d. Mite galls on leaves of Exochorda. PLATE XVI a. Boxwood leaf miner. White spots on leaves indicate infestation. Lower epidermis has been removed from two leaves, showing maggots. Natural size. b. Work of arbor vitae leaf miner, twice enlarged. PLATE XVU. a. Rhododendron borer. Appearance of mfested stems showing adult. Natural size. b. Gall of blue spruce. Natural size. c. Spruce gall. Natural size. PLATE XVIII. a. Pine bark aphid in small tufts on twigs and leaves. Natural size. b. Otiorhynchus sulcatus Fabr. Larva, pupa, and adult. Twice enlarged. c. Exit holes of white pine weevil. Natural size. PLATE XIX. a. Larkspur leaves curled by cyclamen mites; healthy leaf at left. Somewhat reduced. c. Iris root borer, b. Adult of iris root borer. Natural size. Natural size. PLATE XX. Adult of stalk borer. Natural size. Work of columbine leaf miner. Natural size. c. Immature stalk borer in corn. Natural size. Rhododendron leaves injured by rhododendron lace bug, which may be seen on lower surface at right. Leaf at left shows appearance on upper surface. University of Connecticut Libraries 39153028896652