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Historic, archived document
Do not assume content reflects current scientific knowledge, policies, or practices
wei — '. of Cntomclopry and Plant Que ■->.. UNITED STATES DEPARTMENT OF AGRICULTURE LIBRARY
BOOK NUMBER
1 EnS23
no.3U
new series
'Im
U. S. DEPARTMENT OF AGRICULTURE,
DIVISION OF ENTOMOLOGY— BULLETIN NO. 54, NEW SERIES.
L. O. HOWARD, Entomologist.
<y?y</i
/4&3</
Principal Insects Liable to be Distributed '
<"'e.
on Nursery Stock.
Prepared Under the Direction op the Entomologist,
NATHAN BANKS,
Assistant Entomologist.
WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1902.
35223c>
LETTER OF TRANSMITTAL.
U. S. Department of Agriculture,
Division of Entomology, Washington, D. C, April °29, 1902. Sir: I have the honor to transmit for publication a manuscript pre- pared by Mr. Nathan Banks, of this office, in which are considered the principal insects liable to be distributed upon nursery stock. The inspection of nursery stock under State laws has become so general throughout the United States that the desirability of some publication of this sort has become very evident. I had the matter in mind last autumn, and at a conference of the official horticultural inspectors for the United States, held at Washington October 11-13, 1901, a resolu- tion was unanimously passed requesting this Department to prepare and publish an article on those nursery pests of the country which are capable of transmission on nursery stock to the injury of the pur- chasers. Since it is desirable that this manuscript shall be put in available shape for distribution to all horticultural inspectors and to all nurserymen and others immediately interested, I recommend that it be issued as Bulletin No. 34, new series, of this Division. Respectfully,
L. O. Howard,
Entomologist. Hon. James Wilson,
Secretary of Agriculture.
CONTENTS
Page.
Introduction - 9
Tabular statement of insects upon the tree in winter 9
Tabular statement of insects feeding on the buds and young leaves in early
spring - 10
Hemiptera (bugs, scale insects, plant-lice) 10
Family Coccidge (scale insects) 11
Table of scale insects - 11
The peach lecanium 11
The oyster-shell bark-louse 12
The scurvy bark-louse 14
Aspidiotus ( circular or round scales) 14
Table of Aspidiotus 15
The San Jose scale 15
The European fruit scale 18
Putnam's scale 19
The cherry scale 19
The walnut scale 19
The greedy scale 20
The grape scale 20
The peach scale 21
The rose scale . 23
Family Aphidre (plant-lice ) 23
Table of plant-lice 23
The woolly apple aphis 24
The black peach aphis 25
Apple plant-lice 26
The plum plant-louse 26
The cherry aphis 27
Family Psyllidae 27
The pear-tree psylla 27
Family Membracidse . 28
The buffalo tree-hopper 28
Lepidoptera ( butterflies and moths ) 29
The apple-tree tent caterpillar 29
The fall web worm 30
The brown-tail moth 31
The leaf-crumpler 32
The white-marked tussock moth 32
The gipsy moth 33
Cankerworms 35
The peach-tree borer 35
The peach twig-borer 36
The bagworm 37
Other caterpillars . .r 38
5
Page.
Coleoptera ( beetles, weevils ) 38
The round-headed apple tree-borer 39
The flat-headed apple tree-borer 40
The sinuate pear-borer 40
The fruit-tree bark-beetle 42
The apple twig-borer 43
Acarina (mites) 43
The pear-leaf blister-mite 43
Insects infesting fruits ...,... = 45
ILLUSTRATIONS.
Page.
Fig. 1 . Lecanium nigrofasciatum 12
2. My tilaspis pomorum 13
3. My tilaspis pomorum 13
4. Chionaspis furfurus 14
5. Aspidiotus perniciosus, on branch 16
6. Aspidiotus perniciosus, female 17
7. Aspidiotus perniciosus, on fruit and branch 18
8. Aspidiotus ostrereformis 19
9. Aspidiotus juglans-regiae 20
10. Aspidiotus rapax 21
11. Diaspis pentagona 22
12. Auiacaspis rosa? 22
13. Eggs of plant louse 23
14. Schizoneura lanigera 24
15. Schizoneura lanigera, work on roots 24
16. Aphis persicse-niger 25
17. Psylla pyricola 27
18. Ceresa bubalis 28
19. Clisiocampa americana 29
20. Hyphantria cunea 30
21. Euproctis chrysorrhea 31
22. Orgyia leucostigma r . .. 33
23. Porthetria dispar, moth 33
24. Porthetria dispar, larva .'■ 34
25. Porthetria dispar, chrysalis 34
26. Alsophila pometaria, moths 35
27. Alsophila pometaria, stages _ . 35
28. Paleacrita vernata, moths . 35
29. Paleacrita vernata, stages 35
30. Sanninoidea exitiosa 36
31. Anarsia lineatella 36
32. Thyridopteryx ephemera?formis, cases 37
33. Thyridopteryx ephemer?eformis, insects 37
34. Tmetocera ocellana, larva 38
35. Tmetocera ocellana, work of 38
36. Saperda Candida 39
37. Chrysobothris femorata 40
38. Agrilus sinuatus, stages 40
39. Agrilus sinuatus, work of 41
40. Scolytus rugulosus 42
41. Amphicerus bicaudatus 42
42. Rhagoletis pomonella 44
43. Rhagoletis cingulata 45
7
THE PRINCIPAL INSECTS LIABLE TO BE DISTRIBUTED ON
NURSERY STOCK.
INTRODUCTION.
In preparing this descriptive catalogue of the insects liable to be transported upon nursery stock, it has appeared that there is a great disparity of views as to what insects should be included. To include only such as are known to be very destructive would exclude a great many species that will be found by anyone who examines a tree in the fall or early spring. To include all the species that are known to be found in any stage upon fruit trees in winter would make the list too bullry. Therefore, all species known to be of more than local interest have been treated. Notes on the species infesting fruits are added at the end. The insects have been arranged according to their natural orders, and in the Hemiptera (bugs, scale insects, plant-lice) according to the families. In the Coleoptera (beetles, weevils) and Lepidoptera (but- terflies and moths), such an arrangement did not seem desirable. No account of the remedies to be recommended or used is given, as these differ greatly, according to locality and conditions, and the various State laws specify certain treatments.
It will be a great help to those interested in the growth and sale of young fruit trees to be able to recognize the appearance of the various insect pests during the winter; therefore, much attention has been paid to this phase of the subject.
In using this bulletin one should remember that, besides the insects here treated, there may be upon a tree other insects of less importance.
TABULAR STATEMENT OF INSECTS UPON THE TREE IN WINTER.
Insects upon the roots:
Forming swellings on apple roots Woolly aphis.
On peach and plum roots Black peach aphis.
Insects upon the bark of trunk or branches:
Plant-lice or aphids Woolly aphis.
Small brown clear-winged insect in the crevices of bark Pear psylla.
Scale insects or bark-lice See Coccidae.
Caterpillars in cases or cocoons Fall webworm, bud moth, apple
Bucculatrix, codling moth, pistol-case and cigar-case bearers.
In nests or bunches of shriveled leaves attached to branches Leaf-crumpler,
and brown-tail moth.
10
Insects upon the bark of trunk or branches — Continued.
In a case or bag hanging from twigs Bagworm.
Clusters of eggs on bark Cankerworms, tussock moth, and gipsy moth.
A belt of eggs around twigs Apple-tree tent caterpillar.
Single small blackish eggs often in groups on twigs or branches Plant-lice.
Smaller reddish eggs Clover mite.
Insects beneath the bark:
Tiny holes usually near a crotch, each covered by a bit of frass Peach
twig-borer.
Small brown beetle within the twig .Apple twig-borer.
Small holes in bark of trunk or larger branches Fruit-tree bark-beetle.
A gummy exudation of sap at base of tree Peach tree-borer.
Discolored spots or cracks and evidences of frass Round-headed and
flat-headed apple tree-borers, and sinuate pear borer.
TABULAR STATEMENT OF INSECTS FEEDING ON THE BUDS AND YOUNG LEAVES IN EARLY SPRING.
Feeding on the buds or young shoots Bud worm, peach twig-borer, leaf-crumpler,
brown-tail moth, pistol-case and cigar-case bearers. Feeding upon the leaves:
Plant-lice Apple plant-lice, plum plant-louse, and cherry aphis.
Caterpillars in tents Apple-tree tent caterpillar.
Hairy caterpillars Tussock moth, brown-tail moth, gipsy moth.
Bare caterpillars Canker worms.
A blister or gall upon leaves Pear-leaf blister-mite.
Small caterpillars within little cases Pistol-case bearer, cigar-case bearer,
leaf-crumpler, and bagworm.
HEMIPTERA (BUGS, SCALE INSECTS, AND PLANT-LICE).
The members of this order obtain their food (which is liquid) by sucking it up a slender tube into the mouth cavity. This tube or beak is composed of several needle-like pieces so shaped and arranged that they inclose a minute channel up Avhich the liquid food is drawn. The beak is inserted in the plant often to some distance beneath the surface. The members of this order do not pass through a pupal or chrysalis stage like the butterflies and moths, but there is an approach to it in the males of the scale insects. The insects of this order to be treated are arranged in four families, which may be separated, for our purposes, as follows:
The insect from above apparently without legs, antenna?, or wings, and fixed to the
host plant; the adult male (not often seen) usually has two wings Coccidse.
I scale insects). The insect shows distinct legs and antenna', and often four wings.
Most of the specimens wingless, and provided with two small tubes or cornicles
(see fig. 16) near tip of body; not hopping when disturbed Aphididae
( plant-lice). Adult always winged, without the cornicles; hopping when disturbed.
The prothorax not enlarged, with hyaline wings Psyllidse.
The prothorax greatly enlarged; wings obscured Membracidae.
11
FAMILY COCCIDiE (SCALE INSECTS).
The scale insects, or bark-lice, are readily known from most insects in that the stages commonly seen are immovably fixed to the bark or leaf, and show no outward sign of legs or other structures. For a short time after birth the}" are active, crawling creatures, arid distribute themselves over the surface of the plant. Having selected a location, they push their long and thread-like beaks deep into the tree and pro- ceed to suck up the sap. As the}^ grow the protected or covered bark- lice secrete a waxy substance that hardens and forms the scale. When the insect molts the old skin or exuvium remains attached to the scale. The shape, color, and position of this exuvium is of great value in identifying the species.
Their small size and similarity of appearance makes their determina- tion difficult, and it is rarely safe to determine the species by a few individuals, but on a moderately infested branch one is apt to find some specimens that are quite characteristic of the species.
The unprotected bark-lice, such as the Lecaniums, secrete no cover- ing scale.
TABLE OF SCALE INSECTS.
1. Soft scales, without a shield-like covering, very convex, on peach or plum.
Lecanium nigrofasciatum.
2. Armored scales, with a shield- like covering and showing an exuvial spot, much
less convex than Lecanium 3.
3. The exuvium shows as a circular spot situated near the center or at least remote
from the edge of the scale; the adult female scale more or less circular, rarely whitish in color Aspidiotus.
4. The exuvium showing as a more or less ribbed, elliptical spot at the end or close
to one edge of the scale; scales usually whitish in color; if not, then of an oyster- shell shape 5.
5. Scale brownish; the female of an oyster-shell shape, male ovate.
Mytilaspis pomorum.
6. The scale whitish, female not oyster-shell shaped, male scale elongate ...7.
7. The female scale plainly ovate, much longer than broad; the male scale having
three longitudinal keels (see fig. 4, d) Chionaspis furfurus.
8. The female scale is irregularly circular, but little longer than broad; the male
scale with one median keel 9.
9. Exuvium orange or bright yellowish; on fruit trees; male with keel rather indis-
tinct Diaspis pentagona.
10. Exuvium pale or dull yellowish; on raspberry and blackberry ; male with distinct keel Aulacaspis rosx.
THE PEACH LECANIUM.
(Lecanium nigrofasciatum Perg. — fig. 1.)
This insect, formerly known as L. persicae, is one of the largest of the scale insects, being about one-fifth of an inch long and two thirds as wide. It is elliptical in outline and strongly convex. It is usually of a dull greenish-brown color, sometimes distinctly marked with darker
12
bands. It is found upon the branches of peach and plum, more rarely on apple, and commonry occurs on the under side of the branch, the upper side of which is covered with a black fungus that grows on the honey-dew dropped b}T the Lecaniums from the branch above. The females pass the winter in the adult condition. The eggs are developed b}^ the latter part of May. The young hatch early in June and con- tinue for fully a month (June 10 to JuljT 15). The young larvas are flat, uniformly pale yellow, and with a thin marginal rim. They become stationary in a few weeks. By the middle of July the male pupee are deA^eloped, and by the 22d the first winged males appear. There is but one brood a year, and the best time for treatment will be during July.
Fig. 1.— Lecanium nigrofasciatum Perg.: aduKs at left, young at right. (Howard).
There is another species of Lecanium (Z. prunastri), less commonly found on plum. The female is much like that of the peach Lecanium, but the insect passes the winter in the larval state, not maturing till May. The young hatch in July, migrate to the leaves, and in the early fall return to the branches, where they pass the winter. It has rarely been found in this country outside of New York State.
THE OYSTER-SHELL BARK-LOUSE.
| Mytilaspis pomorum Linn. — figs. 2 and 3.)
The oyster-shell bark-louse is one of the best known enemies of the orchardist. It is a dark, slightly convex scale, elongate and usually curved in outline, much resembling a miniature oyster shell. When crowded upon the tree they are apt to he less curved and often quite straight. The elongate exuvium is situated at the small end. Its elongate shape and dark color at once separate it from all other com- mon orchard scales. The eggs, which are whitish in color, are deposited in late summer, and occupy the posterior two-thirds of the scale. The female dies, but the scale remains to protect the eggs during the winter. The young hatch in May or early June, crawl out upon the
13
Fig. 2,—Mytilaspis pomorum: a,b, females; c, scales on twig; d, male scale. (Howard.)
Fig. 3.— Mytilaspis pomorum; a, male; c, larva; e, female; b and d, details. (Howard.)
14
twigs and small branches, and locate there permanently. In a day or two the}7 begin the formation of the scale. The male scale is much smaller than the female, elongate, wider behind than in front, and little, if any, curved. It is uncommon on apple, but often found on other food plants. The winged male insect appears in midsummer. There is but one brood a year in the North, but in parts of the South there are apparently two broods; the second one hatching about Sep- tember 1. The 03Tster-shell bark-louse is widely distributed and attacks a great variety of trees, but is especially partial to apple.
THE SCURFY BAEK-LOUSE.
(Chionaspis furfurus Fitch — fig. 4.)
This common orchard scale is readily known by its whitish color and ovate form. The adult female scale is rather flat, irregularly ovate in outline, with the yellowish exuvium at the apex. The life history is
similar to that of the o}^ster-shell bark-louse. The eggs are laid in the early fall and occupy the greater part of the scale. The mother dies and the scale re- mains on the tree during the winter to protect the eggs. The young hatch during the latter part of May or early in June. The male scale, which is often very abundant, is much smaller than the female, snow-white in color, and fully twice as long as broad, with nearly parallel sides and three keels or ridges. The winged male insects issue in Sep- There is but one brood in the North, but probably two or even three in the South. The scurfy bark-louse* is widely distributed and occurs on most orchard trees, but chiefly on apple and pear.
a. 3
Fig. 4. — Chionaspis furfurus: a, b, infested twigs; c, female; d, male. (Howard.)
tember.
Aspidiotus (Circular or Round Scales).
To this genus belongs the most destructive known species, the San Jose scale. The other species, however, often cause much damage. There is a considerable resemblance among the various species, so that it is difficult for any inexperienced person to determine them. The final characters that separate species are based on the structure of the pygidial plate of the adult female scale. To observe this it is necessary that a specimen be boiled in caustic potash and mounted in balsam on a glass slide. When this is examined under a microscope the lobes, spines, hairs, and sinuations of the margin of the plate
15
appear quite distinctly. Thus, the characters that may be used in the field are not final and only comparative, and great care must be exer- cised, especially when only a small amount of material is available, and any doubt can be settled only by sending the material to some competent authority who can mount and microscopically examine the species.
TABLE OF ASPIDIOTUS.
1. Scale of adult female circular, with exuvium central, dark-colored, the exuvium
pale yellowish when dark waxy outer covering is rubbed off; scale not very con- vex, about 2mm in diameter; half-grown scales are nearly black and show a
central nipple surrounded by one or two depressed rings pernieiosus Comst.
Scale of adult female not circular, the exuvial spot at one side of the center; the half-grown scales usually paler and without the central nipple surrounded by depressed ring 2.
2. Adult female scale dark-colored, about 2mm in diameter; exuvial spot orange
or reddish colored A. forbesi, ancylus, and ostreseformis.
Adult female scale paler, or larger, or with white center 3.
3. Scale of adult female about 2mm in diameter, yellowish or pale brownish ,*wTith a
white center, quite flat; on grape uvse Comst.
Scale of the adult female very convex, about 2iu,m in diameter, of a uniform drab
or yellowish-brown color, the exuvial spot showing reddish, but not commonly
exposed rapax Comst.
Scale of the adult female large, nearly 3mm in diameter, flat, and pale-grayish in
color; the exuvium reddish or orange juglans-regise Comst.
In identifying scale insects by means of the above table, scales should be examined from bark or fruit as clean as possible, and where the scales are not crowded and have room to normally develop. When thickly massed they lose their characteristic shape and appearance, and on sooty or dirty bark they are discolored and abnormal.
THE SAN JOSE SCALE.
(Aspidiotus pernieiosus Comstock — figs. 5, 6, and 7.)
The San Jose scale is known to every orchardist by hearsay, but few, however, can distinguish it from allied scales, such as ancylus, forbesi, and ostreseformis. On badly infested trees the scale presents the appearance of dark gray, scurfy patches. The individual scale is about 2mm in diameter, usually nearly circular in outline, of a grayish color, with the central darker nipple surrounded by one or more quite distinct yellowish or pale grayish rings. When the scales are crowded the outline is more or less distorted. In none of the allied forms is the adult female scale as nearly circular as in the San Jose scale. When on fruit or young twigs there is often a reddish discoloration around the scale. Putnam's scale and the cherry scale have a brighter colored exuvium, situate one side of the center. The cherry scale is often much paler than the San Jose scale. The European fruit scale has an exuvium similar to the San Jose, but lacks the darker nipple;
16
moreover, the exuvium is plainly not at the center of the scale. The male of the San Jose scale is about two times as long as broad; broader at one end than at the other, with a large, dark exuvium, showing a central nipple. It is situated toward the small end of the scale. The male of the European fruit scale is not so elongate, and the exuvium is but little darker than the scale and nearer to the small end than in the San Jose scale. The male of Putnam's scale is as elongate as that of San Jose, but has an orange exuvium. The male of the cherry scale is in shape much like that of the San Jose scale, but the exuvium is of a brighter }Tellow, the scale usually being paler than the San Jose.
« 4
Fig. b.—Aspidiotus pcrniciosus: o, infested twig; b, view of infested bark magnified. (Howard and
Marlatt.)
In general the adult female of the San Jose scale may be distin- guished from its allies b}T the more circular scale, with yellow exuvium, when exposed, more centrally located, otherwise with dark nipple; the male by similar characteristics of exuvium and nipple. But the San Jose scale is most easily recognized by its immature scales, which are almost black, circular, and with a central nipple surrounded b^v one or two depressed circular rings. Such a character is not found in any other of the allied scales.
17
The San Jose scale attacks all of our orchard trees, but appears to be most destructive to pear and peach. The insect is represented in winter by partly grown specimens whose development was stopped by the cold weather. They resume growth in the early spring; the males soon appear, mate with the females, and the latter give birth to living young. At Washington, D. C, this time is about the middle of May, and the young continue to appear for about six weeks. The larva crawls off a little way, settles, and within two days begins the
Fig.
-Aspidiottis perniciosus: a, female; b, margin of pygidium magnified. (Howard and Marlatt.)
secretion of its scale. This young scale is at first white with a swell- ing in the center. If it is situated on green tissue it is apt to pro- duce a redness. In a few days the pale scale becomes nearly black, with a central nipple surrounded by one or two depressed rings. This form is very characteristic of the species. In about twenty -five days another brood of males appears, and in thirty days the females become adult. At about thirty -five or forty days of age the females begin to give birth to living young. Since one of these mother scales may have been born six weeks before another, it results that there is a
24842— No. 34—02 2
18
confusion of generations throughout the summer, breeding constantly going on until late fall. The number of broods will thus depend upon the length of the season.
Fig. 7. — Aspidiotus perniciosus: Infested fruit and branch, and enlarged scales. (Howard.)
THE EUROPEAN FRUIT SCALE.
(Aspidiohis oslreseformis Curtis — fig. 8.)
This species can usually be readily separated from the San Jose scale by the characters mentioned under that species, but it is practi- cally impossible, without making a microscopic mount, to distinguish it from Putnam's scale and the cherry scale. The cherry scale, espe- cially when on cherry, is more shining and often shows a grayish margin. The European fruit scale occurs on all orchard trees, but only, so far as known, in certain Northern States. The winter is passed by the partl}T grown specimens, which become mature toward the last of June, and soon begin to give birth to living young. The young continue to appear for several weeks. There appears to be but one brood a year, at least in the Northern States.
19
PUTNAM'S SCALE. (Asjridiolus ancylus Putnam.)
This scale is widely distributed and attacks all orchard trees. In general appearance it is like the San Jose scale, but at once known by the exposed orange exuvium, the less circular scale, and by the half- grown }Toung having no depressed ring around the nipple. It can be separated from the European fruit scale and from the cherry scale only b}7 a microscopic examination of mounted specimens. It is usu- ally much darker than the cherry scale, the exuvium usually a brighter orange, and the scale more conical than that species. Specimens vary, however, a great deal in these points. The insect winters in a nearly full- grown condition. The males appear in April, soon pair with the females, and the latter deposit eggs in the late spring or early summer. The young beg-in to hatch early in July and continue dur- ing the month. There is but one brood a year.
THE CHERRY SCALE. (Aspidiotus forbesi Johnson. )
This scale is similar to Putnam's and to the European fruit scale, but some- times, especially on cherry, it is more shining, and presents a gray rim around the scale, which is commonly natter than the allied species. It attacks all orchard trees, but is rarely com- mon. It winters partly grown, like its allies. The male issues in April. The eggs are laid in April or early May, the young hatching- during Mivy and part of June. There appears to be two broods a year, the males of the second brood issuing during the latter part of July and the young during August and September.
Fig. 8. — Aspidiotus osfreivformis: a, scales on twig; b, natural size; c, immature stage; d, female; e, male; / and g, in- side of scales. (Marlatt.)
THE WALNUT SCALE.
(Aspidiotus juglans-regix Comstock — fig. 9.)
This insect is at once recognized by the large size of the adult female scale, it being the largest of our species of the genus, the scale often being 3mm in diameter (one-twelfth inch), while the San Jose scale is scarcely 2mm in diameter. The adult female scale is irregularly circu- lar in outline, quite flat, and of a pale grayish or dirty- white color. The exuvial spot is reddish or orange and situated one side of the cen- ter. The scale often appears to be less closely attached to the bark than with the other species of this genus. The male scale is elliptical
20
and much smaller than the female. The adult female scale hibernates, and deposits eggs in early spring. The males from them issue early in June. Eggs are deposited again in June, so that there appears to be two or possibly three broods in the South. This species is not abundant, but liable to be found on almost any orchard tree.
Fig. 9.
Aspidiotus juglans-reffix: a, female; b, male; c, pupa; d, e, infested twigs. (Howard.)
THE GREEDY SCALE.
(Aspidiotus rapax Cornstock — fig. 10.)
This is quite a large species, readily distinguished from the others we have treated by its very convex scale and uniform drab or yellow- ish-brown color, except for the dark brown exuvium which often shows near the center. The adult female scale is less circular than most of the other species, and does not always show the exuvial spot, which is at one side and covered with a film of secretion. The male scale is much smaller, and elliptical in outline. The young are nearly circular, with a central nipple often surrounded by a pale gray ring. This scale is veiy abundant in California and has spread somewhat eastward, especially in the South. It attacks various orchard trees, but more commonly the orange. It is a scale that is liable to be found more commonly in the future, and orchardists should be on the lookout for it. The greedy scale, in California, winters in all stages.
THE GRAPE SCALE.
( Aspidiotus uvse Cornstock.)
This is a more or less elliptical scale, with the exuvium rather nearer one end. It has a yellowish or pale brownish color, with a whitish center near the exuvium, the latter of a pale yellow. The scales are often found in a longitudinal row. and rarely infest both sides of the
21
same branch. It winters in the egg stage. The young hatch in May; the males issue in the summer. There is but one brood a year. It is practically confined to the grape, but has been found on a few other plants, and may spread to fruit trees.
Fig. 10. — Aspidiotus rapax. Scales on twigs, and enlarged. (Howard.)
THE PEACH SCALE.
(Diaspis pentagoria Targ. Tozz. — fig. -11. )
The peach scale, sometimes known as the '"whitewash scale,'1 is of a
ig]
gra}rish white color, rather flat and irregularly circular or slightly
Fig. 11— Diaspis pentagona: a, infested branch; h, female; c, male; d, group of males. (Howard.)
ovate in outline, never as elongate as the scurfy bark-louse. The exuvium is often a little way from the margin, and is yellowish or
09
orange in color. Its pale color and elongate exuvium will readily separate it from all other scales on orchard trees. The insect passes the winter with the mature females and the male scales. The males hatch in early spring. The eggs are laid early in May. and the larvae hatch in about ten days. The males again commence to issue by the middle of June, and the females begin egg-laying by the end of June. The second generation is full grown by the middle of August, and these in time soon begin to lay eggs for the brood that will winter as mature females and undeveloped males.
Fig. 12.—Aulacaspi.< r<>.<;r ; l, infested branch; la, female: lb, male. ^ComstockO
The male scale (fig. 11, c. <1) is elongate, about three times as long- as broad, slightly wider behind than in front, with a median keel, and snow white in color. The male scales appear to be most numerous on the lower parts of the branches and near the base of the trunk and often so matted as to make the trunk or lower branches absolutely snow white. The peach scale is becoming common in many of the Southern States and as far north as Pennsylvania. It infests plum, cherry, and peach, and less commonly other plants.
23
THE ROSE SCALE.
(Aulacaspis rosse Sandberg — fig. 12. )
This species is similar to the peach scale, and, indeed, the easiest way to distinguish between them is by their host plants. The peach scale does not affect the host plants of the rose scale, which are roses, raspberry, and blackberry. The scale covering is much more thin and delicate and the exuvium is usually of a paler or duller yellow than in the case of the peach scale. The keel or ridge of the male is more distinct. The life history of this species does not appear to be well known in this country. It winters, as a rule, in the egg as far north as New Jersey; but mature females and immature females and males may be. found in winter. In the early spring one often finds the female scales surrounded by a radiate row of male scales. It is probable that there is more than one brood in a year, at least in the South.
FAMILY APHIDJE (PLANT-LICE).
The plant-lice are small, sluggish insects found on the under surface of leaves or on the bark and roots. Most of the individuals have no wings, but at times one finds some specimens with delicate transparent wings laid roof -like over the body. They all have distinct legs, a pair of moderately long antennae, and usually quite prominent eyes. They occur in colo- nies, and by their numbers often do a considerable amount of damage. The eggs are found on trees in winter situated near the base of twigs and buds. (See fig. 13.) Thejr are minute, oval, or elliptical shining- black objects. During the warm part of the year the females produce living young, so that one individual may, in a few months, be the parent of a large colony. Many of the species secrete a sweetish liquid from two pre-apical tubes or cor- nicles. This liquid is known as honey-dew, and attracts other insects, especially ants.
TABLE OF PLANT-LICE.
Fig. 13.— Eggs of a plant-louse on twig. (Original.)
Plant-lice on the bark or roots :
With a whitish, woolly, or cottony covering.
Without such covering
Plant-lice on the leaves:
With bluish-white mealy powder; on plum .
Dark brown; on cherry
Green, or faintly reddish; on apple.
Schizoneura lanigera. . . Aphis persicse-niger.
Hyalopterus pruni. Myzus cerasi.
Aphis mali and A. sorbi.
24
THE WOOLLY APPLE APHIS.
(Sckizoncura tanigera Hausmann — figs. 14 and 15.) One often notices on the trunk or larger branches of the apple
Fig. 14.— Schiznneura lanigera; a. agamic female; 5, larva: c, pupa; d, winged female. (Marian.)
small, bluish-white, nocculent patches of a woolly substance, which
indicate the presence of this insect. This cottony substance is a wax-like excretion clinging to the posterior parts of a small, reddish -brown wingless aphis. It is not, however, this form on the trunks that causes injury. This aerial form is but the indication that there are other speci- mens, under the ground and feeding on the roots of the tree. It is the latter form that seriously affects the vitality of the tree. Upon the trunk the lice often cause a roughening of the bark, especially on the new growth around scars made b}T prun- ing. On the roots the lice cause hard and large knots, which eventu- ally produce a " club-footed'1 con- dition of the roots. Such trees usually show their weakness by the fewer and duller colored leaves.
The woolly aphis is practically confined to the apple, but there are a few varieties, such as the Northern
Spy, that appear to be immune against its attacks. The lice com-
Fig. 15.—Schizo)icura lanigera; a, b, work on roots; c, a louse. (Marlatt.)
25
nionly found on the trunk and roots in .summer are the wingless, agamic females. They give birth to living young, and continue to do so, possibly for several years. In spring some of the root-lice will crawl up the trunk and continue to breed there till fall. The colonies of lice on the trunk give rise to winged and migratory females. These, when they locate, give birth to wingless male and female lice, and each female deposits a single winter egg in a crevice of the bark. This egg will, in the spring, hatch into a female which will start a new colony of wingless lice on the trunk. Some of these will, in the summer, crawl down upon the roots and continue to breed there. In the north the colonies on the trunk are apt to be killed out by the severe cold weather, but in warmer latitudes many of them live through the winter, particularly if they are protected by a piece of bark.
THE BLACK PEACH APHIS.
(Aphis persicse-niger E. F. Smith — fig. 16.)
This insect, like the woolly apple aphis, does its great injury under- ground. Its ravages on the roots of peach give a sickly appearance to the foliage of the affected tree, the leaves often being light green or
Fig. 16.— Aphis persicse-niger; winged specimen. (J. B. Smith.)
yellowish in color, and their edges somewhat rolled. The wingless lice on the roots are of a dark-brown color. They breed there con- tinuously without producing males or eggs. Early in the spring some of the root-lice crawl up the trunk of the tree and locate on the young twigs. Here the winged form develops and migrates to other trees- to found other colonies. The winged insect is of a shining black or very dark brown color, the tibiae of the legs being mostly yellowish.
26
Toward midsummer man}' of the lice on the twigs crawl down into the ground and locate upon the roots.
APPLE PLANT-LICE.
The foliage of apple trees, particularly of }Toung trees, often appears curled, and sometimes discolored. This curling is produced by colo- nies of plant-lice. These lice secrete a sticky liquid known as honey- dew, which falls on the leaves below. A black fungus grows upon the leaves covered hy the honey-dew, and this checks their growth. There are several of these plant-lice that attack the leaves of apple; two of them are greenish in color, another has a reddish tinge.
The commoner of the two green species is known as Aphis mali Fitch, (probably Aphis annum Oest). Its life history is about as fol- lows: The eggs are laid on the tree in the fall, partly hidden in crev- ices of the bark; the young hatch from these eggs in early spring, and grow into wingless and sexless lice, known as u stem-mothers, " which produce living young; these young become winged, and, in the early summer, migrate to grasses, where they increase during the summer. In the fall they develop a set of winged, sexless lice, which migrate back to the apple and give birth to sexed individuals; these pair, and the female la}Ts her eggs.
The other green species is Aphis mali Koch. It passes its entire life history upon the apple. The eggs are laid in the late fall. They are black, and occur generally on the trunk and branches. In early spring the young hatch from these and grow into stem-mothers. These produce living young for a number of generations. Many of these of the first two generations become winged, fly to other apple trees, and there start colonies. In October sexed specimens are produced, and the female lays the eggs that are destined to pass the winter.
The other apple plant-louse is A. sorbi Kalt. It is distinctly tinged with red, and the wingless forms have a whitish powdering on the body. This species has a life history similar to that of Aphis malt Fitch., but it is not known what plants serve as its summer hosts.
THE TLUM PLANT-LOUSE. {Hyalopterus pruni Fabr. )
This insect winters in the egg state. The young on hatching in spring go to the under surface of the leaf and there multiply rapidly. Their bodies are covered by a bluish-white mealy powder. Winged specimens are occasionally developed which migrate to other trees. They feed on the plum all summer, but some specimens are said to migrate to grass in early summer. In the fall the winter egg is attached to a plum twig, usually at the base of a bud. At times they do considerable damage to young plum stock.
27
THE CHERRY APHIS.
( Myzus cerasi Fabr. )
This aphis often causes the leaves of the cherry to become crumpled and rolled, and on young trees sometimes does serious damage. The winged and wingless insects are both of a dark brown color, and look much like the black peach aphis. The eggs are laid in the fall on the branches at the base of buds and in crevices of the bark. The young hatch from them in the spring when the buds begin to swell, crawl out upon the buds and growing leaves, and develop into stem- mothers, which give birth to living young. This is kept up all sum- mer until the fall, when the sexes appear and the female deposits her eggs. A number of winged migrants are developed in the spring generations, which serve to spread the species. The insects usually become very abundant by June, but in midsummer they are not as
common.
FAMILY PSYLLIDiE.
THE PEAR-TREE PSYLLA.
(Psylla pyricola Forster — fig. 17.)
This insect is closely related to the plant-lice, but readily known by its longer antennas and its ability to hop. Its color is reddish, with
Fig. 17.— Psylla pyricola; greatly enlarged. (Marlatt.)
some black markings, and with clear wings laid roof -like over the body. When disturbed, it hops and flies away.
28
The insect is widely distributed in the East, but usually is not abun- dant enough to seriously injure the «tree. When they become excess- ively abundant they cause the leaves and fruit to dry and fall. The adult insect hibernates in crevices of the bark. These overwintering specimens are brownish-black in color, with bronzy eyes. They emerge from their hiding places in the early spring, mate, and the female begins to lay eggs before the leaves are ont. The eggs are placed singly or in groups in crevices of the bark of the twigs or in old leaf scars, and, when the leaves have unfolded, upon the leaves themselves. The larvae hatch in about two weeks and begin to suck the juices from the leaves and petioles. They at once commence to excrete honey-dew, and when the insects are extremely numerous the amount of liquid secreted
is enormous and fairly rains from the tree. A black fungus grows on the honey-infested leaves and tree, so that the whole soon has a smoked appear- ance. In about thirty days the larva becomes adult. Development contin- ues all through the summer, and there may be as many a live broods if the season be long enough. It is only known to attack the pear.
FAMILY MEMBRACID^E.
THE BUFFALO TREE-HOPPER.
(Geresa bubalus Say — fig. 18.)
Upon young fruit trees, particularly the apple, one sometimes sees a series of oval or elliptical scars that disfigure and weaken the branches and render them liable to other insect attack. These scars are the results of the work of a curious insect, the buffalo tree-Lopper. It is a grass-green, triangular insect that hops and flies away when disturbed. The pronotum of the thorax is enlarged, as with others of this family, to cover the head and most of the abdomen. The anterior corners of the pronotum project laterally into acute angles. In August and September the adult insects may be found on the trees engaged in oviposition. The female cuts the bark with her ovipositor in two nearly opposite curved slits, so that the bark between is cut loose. Beneath each slit she deposits a series of from 6 to 12 eggs. These eggs hatch in the spring. The dead piece of bark falls out and leaves the elliptical scar, which enlarges with the subsequent growth of the twigs and becomes an inviting point for the attack of other insects. There is but one brood each year.
Fig. 18.— Ceresa bubalis: a, insect; b, recent puncture^ c, eggs; e, old scars. (Marlatt.)
29
LEPIDOPTERA (BUTTERFLIES AND MOTHS).
The caterpillars and cocoons of these insects are known to all. The caterpillars differ from the grubs of beetles in that the}^ have on the under side two rows of prolegs — fleshy, wart-like structures that serve to support the posterior part of the body. The injuries caused by these insects are made by the caterpillar. These have biting mouth- parts that nip out tiny pieces of the leaf or wood, which is then chewed and swallowed. The more injurious forms that are liable to be transported on nursery stock may be arranged as follows:
1. Feeding within the trunk Peach-tree borer.
Feeding within the twigs or leaf -shoots. Peach twig-borer.
Feeding upon the leaves 2.
2. The insect covered by a case Bagworm, leaf-crumpler, pistol-case bearer,
cigar-case bearer. The insect not covered 1 >y a case 3.
3. Making tents or nests Apple-tree tent caterpillar, fall web worm, brown-
tail moth, leaf-crumpler, and bud moth. Without tents 4.
4. Hairy caterpillars .Tussock moth, gipsy moth.
Bare caterpillars Canker worms.
THE APPLE-TREE TENT CATERPILLAR.
(Clisiocampa americana Harr — fig. 19.)
Fig. 19. — Clisiocampa americana: a, b, caterpillars; c, egg-mass, d, pupa, c, female, /, male. (Riley.)
The webs or tents of this caterpillar are frequently found on orchard and nursery trees in May and June. The caterpillars use this tent as
30
a common home, where they retire at night and remain during cloudy days. Each clear morning, at about 8 o'clock, they go out along the branches to the leaves for feeding. The amount of damage done will depend a great deal upon the number of tents upon the tree. The eggs are laid in masses of 200 or 300 arranged in a broad belt around the twig. (See fig. 19, c.) Each end of this belt tapers off to the twig, which character serves to distinguish it from similar egg-clusters of certain other moths. Each mass is covered with a glistening sub- stance that protects it from the rain. The young caterpillars hatch during the latter part of April or earl}7 in May, at about the time when the leaves are expanding. They immediately begin to feed on the leaves near by and to unite them into their tent, which is enlarged as the caterpillars grow. The full-grown larva is nearly 2 inches long,
hairy and black
with a white stripe along the back. On each side of
this is a row of short, yel- low streaks; there are also pale lines on the sides of the body. The under side is nearly black. When ready to pupate the caterpillar seeks some protected spot and there spins its yellowish cocoon, and soon changes to a brown chrysalis. The moth, which is brown, with oblique white bands across the forewings, emerges in a week or so and deposits her egg-mass and dies. There is but one brood a year.
THE FALL WEB WO KM.
(Hyphantria cunea Dru. — fig. 20. )
During the summer and early fall webs or tents sim- ilar to those of the apple- tree tent caterpillar are often seen among the terminal branches of fruit trees. These are the work of the fall webworm. The eggs of this moth, 300 to 500 in num- ber, are laid in patches on either side of the leaves in June. The larva' issue from June to August, and at once begin their web. They eat only the upper surface of the leaf, leaving the veins and the under surface untouched. The young caterpillar is pale yellowish, with dark spots along the sides and covered with scattered hairs. The full-grown
Fig. 20. — Hyphantria cunea: moths and cocoons. (Howard).
31
caterpillar is velvety black above, the sides have two yellow stripes, and between them are many blackish patches and dots. The 3^ellowish or brownish hairs are mostly in tufts which arise from tubercles or warts. Some specimens are quite pale; others very dark. In Septem- ber or October the caterpillar is ready to pupate, and descends to the main branches or trunk of the tree. Here it makes a delicate cocoon, within which it changes to a chrysalis. The insect passes the winter in this stage, and the moth emerges the following spring. The latter has white, sometimes spotted wings, and expands about an inch and a half. There is but one brood each year in the North, but from New York city south there are two broods, the caterpillars of the second making their appearance in August.
THE BROWN-TAIL MOTH.
(Euproctis chrysorrhea Linn. — fig. 21.)
This insect, at present confined to certain parts of eastern Massa- chusetts, is such a dangerous pest that all interested in nursery trade
Fig. 21. — Euproctis chrysorrhea. Moths, larvse, and cocoons. (Howard.)
should be able to recognize it. During winter their small but very compact webs or nests attached to the terminal twigs are very promi- nent objects and will aid in distinguishing the species. In midsummer the eggs may be found in patches of two or three hundred attached to the under side of a leaf near the tip of a branch. The egg mass is covered by a dense layer of brown hairs from the tip of the abdomen of the female. The young hatch in August and eat the surface of the leaf. As soon as it is devoured they draw another leaf to it, until
32
in the fall they have quite a tent. On the approach of winter they strengthen their tent and use it to shelter them during the winter. In spring they come out, eat the unfolding buds and tender leaves, and thus do great damage. The full-grown caterpillar is about li inches long, dark brown, mottled, and spotted with orange, and clothed with reddish-brown hairs and two rows of dense tufts of white hair, along the upper side of the body. By the middle of June the cater- pillars are ready to pupate, and each makes a cocoon attached to a terminal branch, or sometimes elsewhere on the tree, or even on some other object. These cocoons are often close to each other, so as to form quite a mass. The moths emerge in a few weeks. They have white wings, and the females a brown tip to the abdomen. There is but one brood each year.
THE LEAF-CRUMPLER.
(Mineola indiginella Zell.)
The presence of this insect is easily recognized in winter by the clusters of brown, shriveled, and parti}" eaten leaves fastened together and to the twigs by silken threads. Within each cluster of leaves is a curved tube, usually sinuate at the small end, and within this tube is the small, brownish caterpillar of this moth. This caterpillar is but half grown. In early spring the larva cuts loose from its fastenings, crawls with its case out upon the branches, and attacks the developing buds and young leaves, thus causing a great deal of injury. The cat- erpillar becomes full fed by the middle of May, and is then of a green- ish color. It pupates in the larval nest, and the moths issue in June or early Jul}". The eggs are deposited in July, singly on the leaves. The young larva, upon hatching, starts to make a little case for itself, which it enlarges when necessary. They feed on all fruit trees, but are partial to apple, and there is but one brood annually.
THE WTHITE-MARKED TUSSOCK MOTH.
{Orgyia leucosligma S. & A. — fig, 22.)
The caterpillar of this moth, which does great damage to shade trees in cities, sometimes attacks apple and other fruit trees. The adult insect is a light-grayish moth, the female wingless, the male with ash- gray Avings, expanding about 1^ inches, and the antennae are feathered. The eggs, 300 to 500 in number, are laid by the wingless female in the fall within a frothy substance, which on drying becomes hard and brittle. The whole is a very prominent whitish mass, often situated partly or wThollv upon the old cocoon. In Ma}' the young larva? hatch and begin eating the foliage. The larva? are full-grown in July, and spin their slight silken cocoons, attached to any convenient spot. The full-grown caterpillar is a very handsome insect, about li inches in
33
length, yellowish, with three blackish stripes along- the body, and a bright- red head. It is clothed with long, scattered hairs, four white
Hf/DfMAN S.C.
Fig. 22. — Orgyia leucostigma. Various stages; eggs at h and k. (Howard.)
tufts on the anterior part of the body, and three long black plumes, two in front and one at the tip of the body. In the North there is
but one brood a year, but from New York city south there are usually two broods, the caterpil- lars of the second appear- ing in early August.
THE GIPSY MOTH.
(Porthetria dispar Linn — figs. 23, 24, and 25. )
Although practically
confined to certain parts
of Massachusetts, this insect is quite liable to spread, and all interested
in orchards and nurseries should be able to recognize this caterpillar.
24842— No. 34—02—3
Fig. 23. — Porthetria dispar: female moth. (Howard.)
34
The eggs to the number of 400 to 500 are deposited in clusters attached to trees, fences, etc. Each cluster is covered with yellow hairs from the body of the female, which causes the mass to resemble a piece of sponge. The caterpillars hatch from April to June, and feed vora- ciously on the leaves, mostly at night. The full-grown caterpillar is about 2 inches long, of a grayish, mottled appearance, with the tuber-
Fig. 24. — Porthetria dispdr. Larva. (Howard.)
cles on the anterior part of the body blue, and those on the hinder part of the body red, all giving rise to long yellow and black hairs. When the caterpillars are about half grown they, begin to crawl down the tree to the ground in early morning, and ascend again for feeding in the B37 Jul}7 they are ready to pupate in a thin cocoon fastened
Fig. 2b.— Porthetria dispar. Chrysalis. (Howard.)
to the trunk of the tree, to a fence, or other convenient object. The pupal period is about ten days, and the moths issue in August. The female moth has whitish wings with several black spots, notably around the outer margin. The male is brownish, with darker undu- late lines and spots. The gipsy moth attacks almost every sort of tree, and there is but one brood a year.
35
CANKERWORMS.
(Figs. 26, 27, 28, and 29.)
These slender, bare caterpillars appear on apple and other fruit
trees in early spring and eat holes in the leaves. As they crawl they
loop up the body, and are thus called "measuring worms" or "inch
worms. " There are two species of the cankerworms, their habits, how-
Fig. 26.— Alsophila pometaria: a, male; b, female. c, d, details. (Riley.)
Fig. 27 .—Alsvpldla pometaria: a, b, f, larva; c, d, segments of same; (Riley.)
e, eggs; g, pupa.
ever, being similar. The eggs are laid in clusters on the tree in the fall and early winter, with the fall species {Alsophila pometaria Harr.); in March or April with the spring species (Paleacrita vernata Peck). The eggs of the former are flattened on top; those of the latter are rounded. The larvae hatch in early spring and at once feed on the
Fig. 28.— Paleacrita vernata: a, male; b, female, c, d, e, details. (Riley.)
Fig. 29. — Paleacrita vernata: a, cater- pillar; b, egg; c, d, segment of caterpillar. (Riley.)
leaves. When full grown the}T descend to the ground and pupate therein, the moths issuing in late fall or very early spring. The females are wingless, and obliged to crawl up the tree to deposit eggs. The males have large, thin, gray wings. There is but one brood each year.
THE PEACH-TREE BORER.
(Sanninoidea exitiosa Say — fig. 30.)
This destructive insect is readily discerned by the presence of a gummy exudation mixed, with f rass and excrement at or near the base of the tree. The parent moth lays the eggs singly (from May to July, according to latitude) on the bark of the tree, usually near the base. The young larva burrows into the bark and mines between it and the
86
sapwood during the summer and fall. It is quiescent during the winter, but resumes feeding in the early spring, reaching full growth by Ma}T or June. The caterpillar is then a little over 1 inch in length, soft, and pale yellowish in color, with a shining, dark-brown head. It transforms to a chrysalis within an elongate cocoon just beneath or sometimes outside of the bark. The moths emerge in Maj^
Fig. 30.— Sanninoidea exiliosa: a, female; b, male; c, larva; d, e, female and male pupse; /, cocoon.
(Marlatt.)
or June. The female has dark-blue fore- wings; the male has clear ones. It primarily attacks peach, but sometimes cherry and plum. There is but one brood each j^ear.
THE PEACH TWIG-BORER.
(Anarsia lineatella Zell. — fig 31.)
The presence of this insect in the winter is quite readily known by bits of frass attached to the bark, often at the crotches of branches or
twigs. Each bit of frass covers the entrance to a small burrow lined with silk, within which the }Toung larva of this insect passes the winter. It is now of a yellow- ish color, with the head and thoracic segments, as well as the last seg- ment, almost black. Early in spring, when the leaves are coming out, the larvae abandon their bur- rows and attack the tender leaf shoots, boring into them from a point a little below the apex, and when one shoot commences to dry the larva leaves it and attacks another, in about two weeks the larva is full grown, and pupates in a slight open cocoon attached to the bark or among the shriveled leaves. The tiny, grayish moth issues in May. Two broods follow this, the larva? boring in the young twigs
Fig. 31.— Anarsia lineatella: a, infested twig; b, same enlarged; c, larva in case, rf, larva en- larged. (Marlatt.)
37
or sometimes in the immature fruit. The larva from the second brood makes the little burrows in the bark in which the insect passes the winter. The peach twig-borer feeds on all stone fruits.
THE BAGWORM.
(Thyridopleryx ephemerxformisHsiw. — figs. 32 and 33.)
The winter cases or bags of this insect, 1^ to 2 inches long, are often seen hanging from the branches of shade trees, particularly arbor-
Fig. 32. — Thyridopteryx-epkemerzeformis. Cases; d, one cut open. (Howard.)
vitae, locust, and basswood, but are not so common on fruit trees, The adult insect is a moth; the female wingiess; the male with four
Fig. 33.— Thyridopleryx ephemerseformis: a, larva; 6, head of same; c, male pupa; d, female pupa, e, adult female; /, adult male— all enlarged. (Howard.)
transparent wings and a black body. The female never leaves her case alive, but in the fall deposits her eggs therein, drops out and dies,
38
Fig. 34.— Larva of bud-moth. (Slingerland.)
the case remaining attached to the tree all winter. In Ma}^ the }Toung hatch, and at once start to make little cases for themselves, which they enlarge as they grow. When read}T to pupate, the caterpillar fastens its case to a twig and transforms to the chrysalis. The male moth appears in August. There is but one brood a }Tear.
OTHER CATERPILLARS.
On the apple tree in winter one may find several other caterpillars in various stages of development. One of them, the pistol-case bearer (Coleophora malivorella Riley), is a small larva with a dark head. It carries with it a case the tip of which is curved over, the whole about one-eighth inch long. It feeds on the buds and leaves in spring. In the fall it fastens itself securely to the twig, and thus passes the winter in an immature condition.
Another is the cigar-case bearer ( Coleophora Jl etc lor r// a Fern.). It has a life history similar to the preceding, but its case is straight, not curved. Both feed on the pear and quince. Small, elongate, white, ribbed cocoons, nearly one-fourth of an inch long, often in clusters, are sometimes seen on apple bark in winter. They indicate the presence of the apple-leaf bucculatrix (B. pomifoliella Clem.). In spring the tiny, delicate moths issue from the cases. The larva? mine the leaves. There are two broods an- nually.
Small, inconspicuous cases, covered with particles of dirt and bark, are, at times, found on the bark of the apple and pear. These con- tain the half-grown larva of the bud-moth {Trnetocera ocellana Schif., figs. 34 and 35). In spring the larva feeds on the buds and young leaves, webbing the leaves in a bunch or nest. They pupate within this nest. The moth issues in Jul}T, and is a grayish insect with a creamy white patch on each fore- wing. During the summer the young larva1 partially skeletonize the leaves, feeding beneath a thin silken web. As winter approaches they migrate to the twigs and form their hibernating cases. There is but one brood a 3^ear.
COLEOPTERA (BEETLES, WEEVILS).
Beetles are easily known by the hard, coriaceous fore-wings that cover and protect the back of the abdomen. Both in the larval and the mature conditions they have biting mouth-parts, and injury is
Fig. 35. — Work of bud-moth larvae in opening twigs. (Slingerland.)
39
sometimes done by both the grub and the beetle. The grubs, to reach the adult condition, pass through a complete change or metamorphosis, like caterpillars, but do not spin a silken cocoon. The grubs do not have the prolegs that are found in caterpillars. The forms to be noticed below may be arranged as follows:
1 . Boring in the twigs Apple twig- borer.
Boring in the trunk or larger branches 2.
2. Making tiny circular holes in the bark Fruit-tree bark-beetle.
Making a sinuate crack or depression - Sinuate pear borer.
piscolored spots on the bark Round-head and flat-head apple-tree borers.
THE ROUND-HEADED APPLE-TREE BORER.
(Saperda Candida Fab. — fig. 36.)
Discolored places on the bark near the base of the trunk may indi- cate the presence of this borer. Sometimes the bark cracks over the burrow and allows the frass or "sawdust" to drop out, and often there
a b c d
Fig. 36.— Saperda Candida: a, b, larva; c, beetle; d, pupa, enlarged. (Chittenden.)
is some exudation of sap. Every unnatural-looking spot near the base of the tree should be examined. The adult of this borer is a grayish, long-horned beetle with two white stripes along its back. They appear in June and July, and lay their eggs in little slits in the bark made by the beetle near the base of the trunk. The larvae or grubs soon hatch and bore beneath the bark, feeding on the sapwood and inner bark, and making flat, shallow cavities, partially filled with frass. The grubs are nearly cylindrical, pale yellowish in color, and when full- grown about an inch long. On the approach of winter they work downward, often below the surface of the ground. In spring they begin to feed again, boring upward. In this manner they feed all summer until cold weather, when they again hibernate. In the spring they resume work, but now they bore more irregularly and further into the tree. In early fall they bore close to the surface, work back
40
a little, and then pupate. Winter is passed in this condition, and in June the beetles cut circular holes in the bark and escape. It thus takes three years to reach maturity. This borer also infests pear and quince, but not so frequently as the apple.
THE FLAT-HEADED APPLE-TREE BORER.
Tig. 37—Chrysobothrisft morata: a, larva: b, beetle; c, head of male; d, pupa, enlarged. (Chitten- den.)
{Clii'L/sohathj'isfeiiiorala Fab. — tig. 37.)
Discolored spots like those caused by the round-headed borer may indicate the presence of this insect. They are. however, often found
farther up the trunk, and even on the larger branches. The adult is a dark, metallic beetle, rather Hat. and about one-half inch in length. The female deposits her eggs in crevices of the bark on the south side of the tree, usually during June and July, but sometimes later. They apparently prefer trees that are weak or dying, but also attack healthy ones. The young larva upon hatching eats through the bark and bores be- neath the surface, leaving a flattened burrow tilled with its frass. Sometimes, when more mature, they bore deeper into the sapwood. The full-grown larva is nearly an inch in length, pale yellowish in color, with the segment next to the head greatly enlarged and flattened. In the spring it bores out nearly through the bark, then moves back a little and pupates. In about three weeks the beetle cuts an elliptical hole in the bark and escapes. There is one brood each year. It attacks apple, pear, cherry, plum, and quince.
THE SINUATE PEAR BORER. (Agril-us simtatus Oliv. — tigs. 38 and 39.)
The larva of this insect bores long, sinu- ate galleries beneath the bark and sapwood of pear, killing tin1 wood and causing the bark above to crack. The elongate bronzy
beetle makes its appearance in May or early June, and lays its eggs in crevices of the bark. The slender, whitish larva burrows beneath the bark, always downward. In the fall the larva becomes dormant, and is then about 1 inch long, quite flat, whitish or yellowish in color,
Fig. SS.—Aririltts sinuatus: a, larva: b, beetle: e, pupa, enlarged. (Origi- nal.)
41
with a brown head, and the segment next to the head much enlarged. In spring the larva resumes feeding and makes broader burrows than in the first year. In late summer or early fall, when full fed, it bores about one-fourth inch into the wood, and there forms an elon-
Fig. 39. — Work of Agrilus sinuatus, reduced. (Smith.)
gate cell parallel with the bark and connected to the outside by an exit hole. Within this cell it winters, pupates in 4-Pr^i an(^ the beetle issues in May or June. It thus takes about two years to reach maturity.
42
THE FRUIT-TREE BARK-BEETLE.
(Scolyius rugvloms Ratz. — fig. 40.)
Small circular holes in the bark of fruit trees indicate this insect, known also as the u peach bark-borer" or " shot-hole borer." The
a led
Fig. 40. — Scolytus r'ugulosus: a, b, beetle: c, pupa; d, larva; all enlarged. (Chittenden.)
adult insect, a tiny black beetle, appears in the latter part of March to the middle of May, and burrows through the bark. Between the bark and sapwood the female makes a burrow and lays her eggs along each
Pig. 41. — Amphicerus bicaudatus: a, beetle; b, pupa: c, larva: d, winter burrow; e, larval gallery;/
work in grape. (Marlatt. i
side. The young upon hatching bore away from the parental burrow, and in about three weeks are ready to pupate at the end of the gallery.
43
In about a week the beetles bore out from their burrows. The result is that the bark is loosened and sometimes the tree girdled. When they attack peach there is a great exudation of sap and a consequent weakening of the tree. There are two and probably three broods a year, but as they start at different times the broods become mixed. It attacks all kinds of fruit trees, and prefers trees that are dying, diseased, or weakened b}r other insects, but healthy trees are not exempt.
THE APPLE TWIG-BORER.
(Amphicerus bicaudatus Say — fig. 41.)
In the fall and winter the adults of this insect bore into twigs of apple and other fruits, as indicated in fig. 41, d. Cutting back from this hole one will find this borer in the adult state — a c}dindrical brown beetle about one-third of an inch long. These holes are their hiber- nating quarters. In the spring the insect works in grape canes, caus- ing the withering of new shoots, as indicated at fig. 41,/*. In the spring the beetles emerge and insert their eggs in diseased or d}Ting twigs of grape, maple, or other plants; the larva bores through the center of the twig until fall, when it pupates. The beetle issues in late fall, and there is but one brood a year. It attacks chiefly appie, pear, peach, plum, and grape.
ACARINA (MITES).
The mites are not insects, although related to them. They are rec- ognized by lacking the distinction between the head and thorax and by the absence of antennae. There are usually four pairs of legs, but in the pear-leaf blister-mite and its allies there are but two pairs. Besides the pear-leaf blister-mite, which is treated below, there are often found upon fruit trees in winter numbers of tiny, roundish, red eggs. These belong to a mite known as the clover mite (Bryobia pra- tensis Gar.). They rarely do damage to fruit trees in the East, but feed on clover and similar plants.
THE PEAR-LEAF BLISTER-MITE.
( Eriophyes pyri Scheut. )
This is a microscopic mite about one one-hundred and fiftieth of an inch long, with a slender body provided with two pairs of legs near the head end. Although each mite is so small as to do little damage of itself, it may become the parent of a vast assemblage capable of doing a great amount of injury. During the winter the mites remain hidden between the bud .scales. Early in spring the mites move to the young unfolding leaves, eat through the under surface, and feed on the interior substance of the leaf. Here the mites increase a thou- sandfold. Some of these mites move out to form new galls, until a
44
Fig. 42.-Rhagoletis pomonella: a, oviposition puncture in apple skin; b, exit hole of larva; c, d, work of larvae in apple; e,f, g, details; h, egg. (Harvey.)
45
leaf becomes thickly spotted with them. Their feeding causes a thickening of the leaf at that spot, commonly called a blister or gall. This blister is at first of a reddish color, but it gradually turns brown, and finally black. In early fall, when the leaves ripen, the mites leave their galls and take refuge in the buds for the winter.
INSECTS INFESTING FRUITS.
Although few of the insects infesting fruit are liable to be trans- ported upon nursery stock, several of them are such destructive pests
as to merit the attention of all interested in horticulture.
* * * * * * *
The codling moth (Oarpocapsa pomonella Linn.) passes the winter as a caterpillar in a cocoon in crevices or under loose pieces of the bark. However, they are not apt to occur on nursery trees. The cocoon is made of whitish silk and partially covered with bits -^
of bark so that it is not easily seen. In early spring they pupate, and the moths issue to lay their eggs on young apples. The larva bores into the apple, usuall}7 from the blossom end, mines to the core, and then, when about full-fed, bores to the surface. It leaves the apple to pupate on the trunk or larger branches of the tree. Some issue in late June or July and again lay eggs on the apple, making a second brood. In the Northeastern States there is but one brood a year. The codling moth also attacks pears and quinces.
The apple maggot {Rhagoletis pomonella Walsh, fig. 42) is a two- winged fly that appears in June and lays its eggs just beneath the skin of apples. The white maggots, upon hatching, burrow throughout the apple in various directions. When full-fed the maggot drops to the ground, under which it pupates and emerges as a fly the next spring.
The cherry fruit-fly {Rhagoletis cingulata Loew, tig. 43) infests cherry in much the same manner as the apple maggot infests apples, and has a similar life history.
The plum curculio (Conotrachelus nenuphar Herbst.) is a small, grayish weevil that passes the winter under the bark of a tree or among rubbish. In spring it deposits eggs within the plum (peach or cherry) and then cuts a crescentic slit in the skin near by. The larva or grub soon hatches and feeds in the fruit, causing it to ripen
Fig. 43.— Rhagoletis cingulata. (Slingerland).
46
prematurely and fall. The grub, when full-grown, passes into the ground and there pupates, the beetle issuing in the fall. The beetle has a peculiar habit of dropping from the tree when disturbed.
The quince curculio (Conotraehelus crataegi Walsh.) is a very similar insect to the plum curculio. It is the cause of knotty or worm}' quinces. The weevil lays her eggs in little pits of the quince eaten by the parent for that purpose. The grubs feed in the quince till the early fall, when they leave it and burrow beneath the ground. Here they pass the winter, pupating in early spring.
The pear midge (Dij:>Ios!s pyrivora Riley) is a tiny, two- winged fly much like the Hessian fly, that appears in the spring and lays its eggs in 3Toung pears. The larva? feed near the core, causing the fruit to shrivel and drop. When full-fed they leave the fruit and pupate about an inch or so beneath the surface of the ground. The winter is passed in this condition, and the flies emerge the following spring.
o
U. S. DEPARTMENT OF AGRICULTURE,
DIVISION OF ENTOMOLOGY— BULLETIN NO. 34, NEW SERIES,
L. O. HOWARD, Entomologist.
Principal Insects Liable to be Distributed on Nursery Stock.
Prepared "Under the Direction of the Entomologist.
NATHAN BANKS,
A sbistq ) j t Entomolcyisi .
.WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1 9 0 2 .
DIVISION OF ENTOMOLOGY.
Entomologist: L. O. Howard.
First Assistant Entomologist: C. L. Marlatt.
Assistant Entomologist.?: Th. Pergande, F. H. Chittenden. Nathan Banks.
Investigators: E. A. Schwarz, D. W. Coquillett, W. D. Hunter, C. B. Simpson.
Apiarian: Frank Benton.
Assistant*: R. S. Clifton, F. C. Pratt, Aug. Busck, Otto Heidemann, A. X. Caudell,
J. Kotinsky. Artist: Miss L. Sullivan.
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nto mo\6gy and Plant Qui,