Orchard injury by the hickory tiger-moth

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scientific knowledge, policies, or practices.

UNITED STATES DEPARTMENT OF AGRICULTURE

Contribution from the Bureau of Entomology
L. O. HOWARD Chie:

Washington, D. C. PROFESSIONAL PAPER. February 4, 1918

ORCHARD INJURY BY THE HICKORY TIGER-
MOTH.

By Dwicut Isety, Scientific Assistant, Deciduous Fruit Insect Investigations,

ae

CONTENTS.

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INTRODUCTION.

The injurious stage of the hickory tiger-moth, [Zalisidota caryae
Harris,’ is a gregarious summer caterpillar (Pls. I, IL) which, al-
though a general feeder on deciduous trees and shrubs, causes occa-
sional injury in orchards of pomaceous fruits and cultivated walnuts.
While in this respect it is a minor pest, its injury, where it occurs,
is severe and conspicuous and is the source of frequent inquiries to
the Bureau of Entomology and to entomologists in the field. The
writer’s attention was frequently called to the work of this cater-
pillar while stationed at North East, Pa., during the seasons of 1914,
1915, and 1916, and there, incidental to the major projects then
under investigation, the seasonal history and habits of this insect
have been studied and the necessary remedial measures determined.?.

HISTORY.

Injury by the hickory tiger-moth was first described by Harris in
3841 (1) in the earliest important work on economic entomology pub-

21 Order Lepidoptera, family Arctiidae.
2The writer was assisted in 1915 by E. R. Selkregg and in 1916 by James K. Primi:

11190°—18

~~

2 BULLETIN 598, U. S. DEPARTMENT OF AGRICULTURE.

lished in America. Since then frequent reports of local outbreaks have
been recorded in entomological literature. Complaints have been
made to the Bureau of Entomology regularly since 1870, and speci-
mens and records of injury have been received annually since 1904.
Yet in spite of this constant occurrence there appear to be no records
of very great destructiveness. The nearest approach to a general
outbreak recorded occurred in 1907, when the bureau received numer-
ous complaints from New England as well as scattered reports
from other parts of the United States and from Canada. When
Harris (1)? first described the adult, larva, and pupa as Lophocampa
caryae, he gave in addition a brief account of the larval feeding and
cocoon-making habits, and listed hickory, elm, and ash as food plants.
Fitch (2) in 1855 gave a further account of larval habits and added
butternut, sumach, and slippery elm to Harris’s list of food plants;
and during this same year the species was listed by Walker (8) and
figured by Herrich-Schiffer (4). In 1882 it was listed by Grote (5).
Few biological data were added until Beutenmiiller (6) in 1890

listed 32 food plants of the hickory tiger-moth. The same year Dyar—

(7), in discussing head measurements of lepidopterous larve, re-
corded nine larva stages of H. caryae. Soule (8) in 1891 first
described the egg and gave life-history records from egg to pupa,
but recorded only seven larva stages. Packard (9) in 1893 also
described the egg and larva stages and of the latter recorded only
five. Eliot and Soule (11) in 1902 gave a popular account of the
life history similar to the previous one by the junior author, and this
later account is the most nearly complete record of its biology.
From 1905 to 1908, inclusive, the period when inquiries made to
the Bureau of Entomology regarding this insect were most frequent,
there were a number of brief references to it by economic ento-
mologists in the northeastern United States. These references were
brief and added little to the published records except to note its eco-
nomic importance. Patch (12) mentions it as a late summer feeder,
Felt (13 and 15) records it as of economic importance in New York,
Sanderson (14 and 19) records it.among apple insects of New Hamp-
shire, Britton (16) refers to it as abundant in Connecticut, and
Gibson (17) records an unusual outbreak for two years in several
Canadian Provinces. Dr. L. O. Howard states that this species was
unusually abundant in Greene County, N. Y., in September, 1917.

COMMON NAME.

This insect was called the hickory tussock moth by Harris (1),

and until a comparatively recent time this name has been used. Com-.

stock (10) called it the hickory tiger-moth. The latter name would

1 Reference is made by number to ‘“ Literature cited,” p. 13.

~~

ORCHARD INJURY BY HICKORY TIGER-MOTH, 3

seem preferable, since the insect belongs to the family of tiger-moths
(Arctiidae) and not to the family of tussock moths (Lymantriidae).

SYNONYMY.

Lophocampa caryae Harris, 1841.

Halesidota annulifacia Walker, 1855.
Phegoptera porphyrea Herrich-Schiffer, 1855,
Halisidota caryae (Harris) Grote, 1882,
Halisidota caryae (Harris) Packard, 1890.

DISTRIBUTION.

The hickory tiger-moth is distributed over the northeastern United
States and the adjacent Canadian Provinces. According to rec-
ords of the Bureau of Entomology and literature, its range ex-
tends from the Atlantic Ocean west to Missouri, Minnesota, and
Saskatchewan, and from the Canadian Provinces bordering the
United States south to North Carolina and southern Ohio. Records
have been taken from the following States and Canadian Provinces:
Maine, New Hampshire, Vermont, Massachusetts, Connecticut, New
York, Pennsylvania, New Jersey, North Carolina, Ohio, Michigan,
Tilinois, Wisconsin, Missouri, Quebec, Ontario, Manitoba, and Sas-
katchewan. It is probably much more frequent in New England
and the Middle States, however, since more than 75 per cent of the
reports of destructiveness have come from this region.

DESCRIPTION OF STAGES.

EGG.
(Pl. II, fig. 4.)

The egg is nearly globular, flattened on the side of attachment, 0.75 mm. in
diameter. The surface is glassy and in color it is a robin’s-egg blue when
first deposited. A brown ring appears on the upper surface about the second
day, and in a few days the egg appears olive brown when viewed from
above, although when viewed from the side it is greenish. In about two weeks,
just before hatching, it becomes leaden blue. Infertile eggs do not change
in color, but dry up in a few weeks. Eggs are deposited in a broad patch of
50 to 400 on the underside of the leaf. The writer has found one patch of
525 eggs.

“LARVA.
(Pll. Pill, sis: £,.2)53>)

Full-grown larva.—Length, 32 to 38 mm. A striking grayish-white and
black hairy caterpillar. It is covered with short spreading tufts of grayish
white hairs, with a dorsal row of contiguous black tufts which appear like a
velvety crest. These tufts occur on the first eight abdominal segments and a
small one may be seen on the ninth. There also may be a pair of slender black
pencils arising from the first abdominal segment, and another pair arising

from the seventh. These pencils may be very long, may be inconspicuous, or

absent altogether. The head and feet are black. The hair arising from the
thoracic segmeuts is ionger than that of the rest of the body and when the

4 BULLETIN 598, U. S. DEPARTMENT OF AGRICULTURE.

larva is at rest covers the head. The spreading side tufts | give the larva a

- depressed appearance. :

First instar (Pl. II, fig. 1).—Width of head, 0.46 to 0.50 mm; total length.
1.5 mm.; when full fed, 3 mm. The head is shining black and is much wider
than the thorax of a newly hatched larva. The body is cylindrical, pale green-
ish white, and marked with black setiferous tubercles. Dorsally the tubercles
appear as follows: On the first thoracic segment, a large dorsal plate and two
very small tubercles on either side; second thoracic segment, one large com-
pound tubercle on either side near the cephalic margin and a very small me-
dian tubercle near the caudal margin; third thoracic segment, 2 conspicuous
tubercles on either side; first to eighth abdominal segments, 3 conspicuous
tubercles on either side arranged in a triangle, two of them being near the
cephalic and one near the caudal margin; ninth abdominal segment, 1 large
‘compound tubercle on each side; tenth abdominal segment, 1 large plate cover-
ing most of the dorsal aspect of the segment. On all the thoracic segments anc
on third to ninth abdominal segments there are 38 small tubercles on each
side; on abdominal segments 1 and 2 there are 4 on each side; and on ab-
dominal segment 10 there is 1 one each side. All the lateral tubercles and
lateral-dorsal tubercles bear 1 white seta. Black sete are all dorsal, 4 arising
from each thoracie segment, 1 from each of the 4 median abdominal tubercles,
and 6 from the anal plate. :

Second instar.—Width of head, 0.65 mm.; total length, 5 to 6 mm. when full
fed. This instar differs chiefly from the preceding in the abundance of long
whitish hairs which arise in considerable numbers from all the tubercles. The
tubercles are larger and contrast strikingly with the color of the body.

Third instar—Width of head from 1.12 to 1.16 mm.;- total length, 10° mm.
when full fed. More hairy than the preceding instar.

Fourth instar (Pl. II, fig. 2).—Width of head, 1.7 mm.; total length, 13 to
14 mm. The dorsal tubercles are nearly obscured by the hair arising from
them. :

Fifth instar.—Width of head, from 1.88 to 2.19 mm., average 2.1 mm.; total
length. 18 to 19 mm. Tufts at sides of each body segment becoming conspicu-
ous. and the black pencils may appear in this instar.

Sixth instar—Width of head, from 2.91 to 3.09 mm., average 3.0 mm.;
total length when full fed. 22 to 25 mm. The side tufts have become so con-
spicuous that they give the larva an almost flattened appearance. The black
dorsal tufts are not yet touching and do not yet form a conspicuous crest.

Seventh instar (Pl. IT. fig. 3) —Width of head, from 3.43 to 3.52 mm., average
3.46 mm.; total length. 27 to 32 mm. Practically the same as the preceding.

Bighth instar.—Width of head, from 4.10 to 4.30 mm, average 4.2 mm.;
total length, 32 to 40 mm, This larva is very much like the preceding if it
has yet to pass through another instar, or if this instar is the last it is like
the mature larva previously described.

Ninth instar (Pl. 1).—Width of head. from 4.7 to 4.9 mm., average 4.8 mm.;
total length, 35 to 42 mm. This instar differs conspicuously from the imma-
ture forms because of the striking black crest. 3

COCOON.
(Pl. ITT, fig. 3.)

The cocoon is usually ellipsoidal, sometimes slightly flattened on one side,
. depending on the material which surrounds it. In length it averages 23 mm.
-and in width 15 mm. The larva mixes most of its gray hairs into the silk,
making the cocoon very hairy. In color it is dirty gray.

ey

OTOL La RT IE LI

ORCHARD INJURY BY HICKORY TIGER-MOTH. 5

PUPA.
(Pl. III, fig. 2.)

‘Length, 10 to 138 mm; width of thorax, 6 mm; width of abdomen, 7.5 mm.
The abdomen is much stouter than the thorax and there is a slight constriction
between them; the wingpads extend to the fifth abdominal segment; on the
esudal end is a transverse row of spines recurved at the end. Color when
newly transformed, yellowish, but soon becoming reddish brown; margins of
segments and spiracles darker,

IMAGO.
(Pl. III, fig. 1.)

The following is Harris’s original description of the moth (1):

* * * very light ochre-yellow in color; the fore-wings are long, rather nar-
row, and almost pointed, are thickly and finely sprinkled with little brown dots,
and have two oblique brownish streaks passing backwards from the front edge,
with three rows of white semitransparent spots parallel to the outer hind
margin; the hind-wings are very thin, semitransparent, and without spots; and
the shoulder covers are edged within with light brown. They expand from
one inch and seven-eighths to two inches and a quarter or more. The wings
are roofed when at rest, the antenne are long, with a double narrow, feathery
edging, in the males and a double row of short, slender teeth on the under-side,
in the females; the feelers are longer than in the other Arctians, and not at all -
hairy; and the tongue is short but spirally curled.

FOOD PLANTS.

The hickory tiger-moth is usually recorded as a general feeder on
the foliage of deciduous trees and shrubs. No less than 49 host
plants from wedely separated families have been listed by various
observers. However, this wide range of food plants is confined to

the nearly mature larva. The number of food plants upon which

larve can develop from egg to pupa is much smaller and, as far as
the writer has observed, is restricted to trees of the walnut and
hickory family and to pomaceous fruits.

The writer has reared larvae from egg to pupa on Japanese walnut,
English walnut, black walnut, apple, and pear. In the field, colonies
have been found frequently on all of the above and also on butter-
nut, quince, and once on white hickory. In spite of its name walnut
and not hickory seems to be its favorite food plant. An egg mass
was found on a sour-cherry leaf, but a colony of larvae were never
found feeding on cherry in the field. Miss Soule (8) records finding
an egg mass on a thorn leaf (Crataegus sp.).

The lots of larvee which were fed on black walnut, Ii apanese walnut,
English walnut, pear, and apple all reached the pupa stage and
appeared normal. In the early larva instars the development was
about the same. The later instars on Japanese walnut developed

Ge: BULLETIN 598, U. S. DEPARTMENT OF AGRICULTURE.

somewhat faster than any of the others, and nearly all of them
attained the ninth instar before pupation, although those hatching
very late passed through only eight instars. Those reared on apple
developed more slowly and passed through only eight stages, while
the larve on pear passed through either eight or nine. The length
of stages of larvee feeding upon these plants will be given in detail
in the discussion of seasonal history. -

In confinement larve would feed on the foliage of many trees
upon which they could not mature. Attempts to rear larve from
hatching to pupation on sour cherry (Early Richmond variety),
red oak, and slippery elm were unsuccessful. Those fed on oak
and cherry passed through the early molts with regularity, but
growth was slower than that of those reared on walnut and apple,
and finally stopped altogether. A few larve that were started on oak
and cherry at the beginning of the second stage reached the seventh,
but were undersized and unhealthy in appearance. Elm was more
distinctly unfavorable than either oak or cherry. Larve placed upon
elm immediately after hatching failed to pass even the first molt, and
those transferred from walnut as late as the fourth stage failed to
pass the seventh.

Table I gives a list of the food plants recorded in entomological
literature and in the records of the Bureau of Entomology with the
authority for the previously published records. In this list nomencla-
ture of the native species is according to Gray’s Manual of Botany,
seventh edition (1907), and the nomenclature for imported species is
that of Bailey’s Standard Cyclopedia of Horticulture.

TABLE I.—A list of native and imported food plants of the hickory tiger-moth
(Halisidota caryde).

Acer saccharinum L. Silver maple. (Beutenmiiller 1890.)

Acer pseudoplatanus L. Sycamore maple. (Beutenmiiller 1890.)
Acer rubrum L. Red maple. (Beutenmiiller 1890.)

Acer negundo L. Boxelder. (Beutenmiiller 1890.)

Acer saccharum Marsh. Sugar maple. (Beutenmiiller 1890.)
Aesculus glabra. Welld. Buckeye. (Beutenmiiller 1890.)
Alnus rugosa (Du Roi). Alder. (Beutenmiiller 1890.)

Betula a. var. papyrifera Marsh. Paper birch. (Beutenmiiller 1890.)
Betula populifolia Marsh. Gray birch. (Beutenmtller 1890.)
Carpinus caroliniana Wall. Hornbeam. (Beutenmiiller 1890.)
Carya sp. Hickory. (Harris 1841.)

Carya alba (1.) White hickory. (Beutenmiiller 1890.)

Carya glabra (Mill.). (Beutenmiiller 1890.)

Castanea dentata (Marsh). Chestnut. (Beutenmiiller 1890.)
Celtis occidentalis L. Hackberry. (Beutenmiiller 1890.)
Crataegus sp. Thorn. (Soule 1891.)

Cydonia ohlaraua Mill. Quince.*

+Copfirmed by writer.

ORCHARD INJURY BY HICKORY TIGER-MOTH. 7

Fagus grandifolia Ehrh. Beech. (Beutenmiiller 1890.)
Frazinus sp. Ash. (Harris 1841.)

Hamamelis virginica L. Witch-hazel. (Beutenmiiller 1890.)
Juglans cinerea L. Butternut.” (Fitch 1855.)

Juglans nigra L. Black walnut.2 (Fitch 1855.)

Juglans regia lL. English walnut.’

Juglans sieboldiana Maxim. Japanese walnut.*

Larix decidua Mill. Tamarack. (Fitch, according to Felt, 1905.)
Lariz laricina (Du Roi). Larch. (Fitch, according to Felt, 1905.)
Ostrya virginiana (Mill.). Hop hornbeam.’

Prunus serotina Ehrh. Black cherry.” (Beutenmiiller 1890.)
Prunus virginica L. Chokecherry. (Beutenmiiller 1890.)
Prunus cerasus. Sour cherry. (Lintner 1891.)

Platanus occidentalis lL. Sycamore. (Beutenmiiller 1890.)
Platanus orientalis L. Syeamore. (Beutenmiuller 1890.)
Pyrus communis L. Pear. (Lintner 1891.)

Pyrus malus L. Apple. (Beutenmiiller 1890.)

Quercus alba L. White oak. (Beutenmtller 1890.)
Quercus palustris Muench. Pin oak. (Beutenmiller 1890.)
Quercus rubra L. Red oak. (Beutenmiiller 1890.)

Rhus sp. Sumach. (Fitch 1855.)

Rosa sp.’

Rubus sp. Raspberry. (Eliot and Soule 1902.)

Tilia americana L. Basswood. Beutenmiiller 1890.)

Tilia alba. White linden. (Beutenmtller 1890.)

Tilia europea. European linden. (Beutenmiiller 1890.)
Salix sp. Willow. (Eliot and Soule 1902.)

Ulmus sp. Elm. (Harris 1841.)

Ulmus americana L. American elm. (Beutenmiller 1890.)
Ulmus campestris L. English elm. (Beutenmiiller 1890.)
Ulmus fulva Michx. Slippery elm. (Fitch 1855.)

SEASONAL HISTORY.

EMERGENCE OF MOTHS.

There is one generation annually. The insect pupates in the fall,
hibernates in the pupa stage, and the moths emerge in early summer.
During the season of 1916 the earliest emergence from a lot of 36
cocoons was June 9 and the latest June 24, the majority emerging
from June 12 to 15, inclusive. No adults were reared in either of the
two previous seasons, but in 1914 larvee were found in the field as
early as June 18, indicating that moths must have emerged as early
as June 1. In 1915 the larve appeared in the field about the same
time as in 1916. The data relating to emergence of moths in 1916
are given in Table II.

4Confirmed by writer.

8 BULLETIN 598, U. S. DEPARTMENT OF AGRICULTURE.

TABLE II.—Time of emergence of adulis of the acters tiger-moth at North
Fast, Pa., 1916.

| Total | Number | Number Total | Number | Number

Date of emergence. | number of of | Date of emergence. | number of of
|of moths.| males. | females. 1 ofmoths.| males. | females,
Bas Pr aia =
JUNC Oe oc ces seca 1 i eee || June 16..... SEs ss eee = Be 1
AE es ae 1 jbl REESE SS ! [Ls aleRes See 2? 1 eee 1
| EES Aaa Se 4 3 1 | eee eee Soe a ge 1
eee nee 8 7 1 | pe ene i Peete t= 1
igbeseacsocose 4 3 1
ESS secs | 3 2 1 25 8

LENGTH OF EGG STAGE.

The length of the egg stage, based on records from 4 egg masses
deposited in 1916, was 15 to 16 days. Two masses of eggs deposited
June 15 hatched July 1; one mass deposited the same day hatched
July 2; the fourth mass, deposited June 16, hatched July 3.

DURATION OF LARVAL FEEDING PERIOD.

The duration of the larval feeding period varies greatly. Miss
Soule (8) records rearing one colony from egg to cocoon in 47
days, which passed through only 7 instars. During the season of
1915 larve reared by the writer on Japanese walnut required from
62 to 85 days from egg to cocoon, averaging 74.73 days. (See
Table IIT.)

Table III.—Duration of the larval feeding period, North East, Pa., 1915.

Duration | Duration | Duration

Number of| of larval lnraamber of! of larval ! Number of} of larval
lindividuals.| feeding |jindividuals.| feeding ee feeding
|

}

period. | period. | period.

Days. | Davs. Days.
1 62 | 1 ri i| 2 79
1 €4 2 7A || 2 80
1 €6 1 75 || 1 82
1 68 || 2 ed ee 85
i 70 |i 1 a7
1 71 | 3 78 foe: 22 1 74.73

1 Average.

During the season of 1916 larve reared on the same food plant
required 80 to 100 days, averaging 89.04 days. (See Table IV.)

TaBLeE IV.—Duration of the larval feeding period, North East, Pa., 1916.

Duration Duration Duration
Number of} of larval Number of} of larval Number of} of larval
larve. feeding larve. feeding larve. feeding
period. period. | period

Days.

er CD SO we ND
VSRR SSS

Bul. 598, U. S. Dept. of Agriculture.

THE HICKORY TIGER-MOTH.

inal.)

o
5D

i

(Or

, ninth instar,

Larve on apple leaves

Bul. 598, U. S. Dept.

of Agriculture.

STAGES OF THE HICKORY TIGER-MOTH.

Fic. 1.—Larye, first instar. Fig. 2—Fourth instar.

(Original.)

Fig. 3.—Seyventh instar.

PLATE Il.

Fig. 4.—Eggs.

Bul. 598, U. S. Dept. of Agriculture. PLATE III.

THE HICKORY TIGER-MOTH AND STAGES.
Fig. 1.—Adult. Fie. 2.—Pupz. Fic.3.—Cocoons. ( Original.)

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ORCHARD INJURY BY HICKORY TIGER-MOTH. 9

The larve reared in 1915 passed through only 8 instars, but the
majority of those reared in 1916 passed through 9 instars. ‘This

_ could not have affected greatly the time required for development,

however, as the few larve which passed through only 8 stages in
1916 required an average of 88.71 days. In 1915 the larve were
reared under natural conditions in bags on a tree, whereas in 1916
all lots but one were reared in batterv jars. The one lot of 22 larvee
reared on the tree in 1916 required from 85 to 92 days from egg to
cocoon, with an average of 87.18 days, very nearly the same as that
of those reared in confinement.

No explanation is offered for the difference in time required for

‘development of larve in the two seasons, but it should be stated

that the season of 1915 was excessively rainy, whereas the 1916 sea-
son was excessively dry. It is probable that humidity affected the
rate of development either directly or by its effect upon the food
plant.

The duration of the larval feeding period varies somewhat when
different food plants are used. ‘The development of those reared ‘on
apple was similar to that on walnut, but a little slower, and the
larvee passed through only 8 stages. The shortest period required
for development from egg to cocoon was 89 days and the longest

was 96 days, with an average of 92.87 days.

Pear seemed a slightly more favorable food plant than apple! The
development of the larve was more rapid, and although the majority
passed through only 8 stages a few passed through 9 stages. Eight-
een larve which passed through 8 stages required from 87 to 91
days, with an average of 88.77 days; 5 larve which passed through
§ stages required from 98 to 100 days, averaging 98.40 days.

The duration of the stages of larve reared on Japanese walnut
during the season of 1916 was as follows:

First stage: Minimum 6 days, maximum 7 days, average 6.12 days; 232
larvee reared.

Second stage: Minimum 4 days, maximum 7 days, average 4.78 days; 232

larve reared.
Third stage: Minimum 5 days, maximum 7 days, average 5.62 days; 232

Jarvee reared.

Fourth stage: Minimum 6 days, maximum 7 days, average 6.02 days; 232
larvee reared.

Fifth stage: Minimum 6 days, maximum 8 days, average 6.25 days: 232
larve reared.

Sizth stage: Minimum 6 days, maximum 13 days, average 8.52 cates 145
larvee reared.

Seventh stage: Minimum 8 days, maximum 20 days, average 12.33 ait 145
larvee reared.

Highth stage (excluding larve that completed their feeding period in this
stage) : Minimum 13 days, maximum 25 days, average 18.03 days; 138 larvee
reared,

10 BULLETIN 598, U. S. DEPARTMENT OF AGRICULTURE.

Highth feeding stage (including only larvee that spun cocoons at end of this
instar): Minimum 19 days, maximum 29 days, average 238.29 days; 7 larve
reared.

Ninth feeding stage (until spinning of cocoons): Minimum 138 days, maxi-
mum 26 days, average 20.95 days; 138 larve reared.

The period covered by the rearing records in 1915 began when the
larve under observation hatched, on July 17, and continued until
time of spinning cocoons, which extended from September 17 to
October 10. In 1916 the earliest larve hatched June 30, and the
first cocoon under observation was spun September 24 and the latest
October 10.

\

DURATION OF PREPUPA PERIOD.

The larva period in the cocoon at North East, Pa., in 1916 aver-
aged between 7 and 8 days. Of 19 larve which spun cocoons on
September 24, 25, and 26, 10 pupated in 7 days and 9 in 8 days.

HABITS.

THE LARVA.

Larve from the same egg mass hatch almost simultaneously and
upon hatching eat the greater part of the eggshells. They are gre-
garious in the early stages, and even in the later stages molt together.
During the first four stages they feed gregariously, beginning to scat-
ter in the latter part of the fourth. If during the first three stages
a larva is separated from its fellows and is placed on a separate leaf
or shoot, it will invariably find its way back to the others within a
few hours. When one leaf or shoot is stripped the larve move in
mass to another, often to another part of the tree.

After the fifth stage the larvee scatter more or less and are solitary
except about molting time. Often they migrate to trees quite a dis-
tance from the one on which the colony started. After the last molt.
the larvee scatter widely.

The molting of the majority of larve from a given egg mass is
almost simultaneous, and at this time the gregarious habit is most
proneunced. Even after larve have scattered over a tree they come
together to molt. A short time before molting a silken mat is spun
upon which the larve rest for about a day before the early molts
and sometimes for several days before later ones. This molting mat
is spun upon a leaf or bunch of leaves, and sometimes before the later
molts on the side of a branch or tree trunk. At each molting period
there are often a few larve which fall behind and fail to molt with
the rest. These invariably develop very slowly and usually do not
mature.

ORCHARD INJURY BY HICKORY TIGER-MOTH. 11

Feeding injury is seldom conspicuous and usually unnoticed until
‘the third or fourth instar is reached when the larve become very
voracious. lLarvee in the first stage are surface feeders. ‘Those on
walnut and pear feed on the underside, eating nearly to the up-
per epidermis. Those on apple and quince feed on the surface.
On these food plants the larvze eat the leaf tissue as they go, while
larvee on cherry and oak leave patches of surface uneaten and also
may feed on either upper or lower surface of the leaf. Larve in the
second stage feeding on walnut and in the third stage on pomaceous
fruits feed at the edge of the leaf, eating everything except the
thicker leaf veins.

The cocoon is spun among leaves or in protected situations on the
ground. If the infested trees are in the neighborhood of buildings
cocoons may be found under boards, behind doors, or in similar
situations.

THE PUPA.

The pupa hibernates on the ground. Moisture is probably neces-
sary for successful hibernation, for from 386 cocoons wintered out
of doors in a screen basket 25 moths emerged, whereas from 21
cocoons wintered in the insectary in a battery jar and protected from
snow and rain, but exposed to the same temperature conditions, none
emerged.

| THE MOTH.

In emerging the moth usually breaks the pupal skin and then
forces its way out of the end of the cocoon. If the cocoon is very
loosely constructed the pupa may break out of it before eclosion, but
this is not usual.

Copulation has been noted as early as the day of emergence and
oviposition as early as 3 days thereafter. One moth continued ovi-
positing for 2 days, day and night, apparently without interruption,
adding eggs to the same egg mass. Oviposition is performed de-
liberately. The moth’s wings are folded back at rest at this time.

Moths oviposit readily in cages without bemg fed. They seem
to prefer to oviposit on Japanese walnut leaves but will place eggs
on cheesecloth or on the sides of the cage. The moths are very
sluggish and can be handled easily in cages.

PARASITES.

This insect is remarkably free from parasitic enemies. None has
been reared by the writer, and as far as he is aware only one species,
Pimpla pedalis Cress (18), has been recorded.

ED BULLETIN 598, U. S. DEPARTMENT OF AGRICULTURE,

ECONOMIC IMPORTANCE.

Injury by this insect is intensive and not extensive. It is due to
the gregarious larve of the early stages which strip branches and
sometimes small trees of their foliage. The injury to young trees in
particular may be severe. After the gregarious habit is lost the
larvee scatter so widely that the injury done by them is inconspicuous.

Infestation by this insect so far as the writer has observed is not
general even within an orchard. Several colonies of larve may be on
one tree, but the writer has never seen a large tree completely stripped.
Usually damage occurs in young orchards on which the codling-
moth sprays have not been applied. The increasing importance of
the cultivated walnut trees in the northeastern United States prob-
ably will cause this pest to become correspondingly more important.

CONTROL.

Spraying with arsenicals is the usual recommendation for the con-
_ trol of this pest. In orchards which have been thoroughly sprayed -
for the codling moth the writer has never noted an infestation.
Nevertheless, the caterpillar soon becomes very hard to poison, and
very large amounts are required to kill it in the later stages.

If control measures are not adopted until the larve are in evidence,
they probably will not be applied until some of the larve are in the
third or fourth instar. Spraying at this time is likely to produce dis-
couraging results. Two trees infested with colonies of fourth-stage
larvee were sprayed with arsenate of lead July 31, 1915; on one the
poison was applied at the rate of 8 pounds (paste) to 50 gallons and
on the other 5 pounds (paste) to 50 gallons. None of the larve died
until two days later on the tree sprayed with the larger amount of
poison, and not until three days later on the tree sprayed with the
smaller amount. On the tree sprayed with the smaller amount about
10 per cent of the larve survived. It was evident that unless they fed
on poisoned leaves continuously for some time they were not affected
at all. Unless the larve are confined on a sprayed tree they are very
likely to migrate to another before eating enough to kill them.

In the gregarious stages colonies of these larve are easily collected
and destroyed. When the infestation is scattered throughout an
orchard this method is much the cheapest that can be employed and is
entirely effective.

On young orchards which would not receive the spring spray ap-
plications for the codling moth, an application about the last of June
ef arsenate of lead (paste), 3 Bouts to 50 gallons of liquid, would
be of value in preventing injury by this bee

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(2)

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(4)

(5)

(6)

(7)

(8)
(9)

(10)

(11)

(12)

(13)

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1841.

1855.

1855.

1855.

1882.

1890.

1890.

1891.
1893.

1895.

1902.

1905.

1905.

1906.

1907.

ORCHARD INJURY BY HICKORY TIGER-MOTH. 13

LITERATURE CITED.

Harris, T. W. A Report on the Insects of Massachusetts Iniurious

to Vegetation. viii+459 p. Cambridge, Mass.
Pages 257-258. Lophocampa caryae.

FircH, Asa. First annual report on the noxious, beneficial and
other insects of the State of New York. Jn Trans. N. Y.
State Agr. Soc., v. 14, 1854, p. T05—-SS0.

Pages 863-867. Lophocampa caryae.

WALKER, Francis. List of the Specimens of Lepidopterous Insects
in the Collection of the British Museum, Part Hage Lepi-
doptera Heterocera. London.

Page 734. Halesidota annulifascia.

HERRICH-SCHAFFER, G. A. W. Sammlung neuer oder wenig bekannter
aussereuropiischer Schmetterlinge. 84+4 p. [120] col. “pl.
Regensburg.

288. Phegoptera porphyrea H-S. mas.—Hales., p. 81, colored.
figure of adult.

GroTr, A. R. New Check List of North American Moths. 73 p.
Page 16. dH. caryae.

BEUTENMULLER, William. Food plants of Lepidoptera No. 13
(Halisidota caryae, Harr.). In Entomologica Americana, v.
Gyno: top: 16;

Dyar, H. G. The number of molts of lepidopterous larve. In
Psyche, v. 5, p. 420-422.

Page 422. H. caryae.

SouLE, Caroline G. Halisidota caryae. In Psyche, v. 6, p. 158-160.

PackarpD, A. S. Studies on the life-history of some boinbycine
moths, with notes on the sete and spines of certain species.
In Ann. N. Y. Acad. Sci., v. 8, p. 41-92.

Pages 65-67. A. caryae.

Comstock, J. H., and Comstock, A. B. A Manual for the Study

of Insects. 701 p. Ithaca, N. Y.
Page 320. HA. caryae.

Extot, Ida M., and Sourr, Caroline G. Caterpillars and their

Moths. xiii+302 p. New York.
Pages 206-211. WH. caryae.

PatcH, Edith M. Brown-tail moth and other orchard moths.
In 20th Ann. Rpt. Maine Agr. Exp. Sta., 1904, p. 153-168, fig.
21-27.

Page 164. H. caryae.

Feit, EK. P. Insects Affecting Park and Woodland Trees, v. 1.

Albany. (N. Y. State Mus. Mem. 8.)
Pages 314-315. H. caryae.

Sanperson, EH. D. Apple insects. Jn 28th Rpt. N. H. Coll. Agr.

& Mechanie Arts, p. 319-342.
Pages 327-328. H. caryae.

lett, E. P. Twenty-second Report of the State Entomologist on
Injurious and other Insects of the State of New York, 1906,
p. 39-186. Albany. (N. Y. State Mus. Bul. 110.)

Page 59. 4H. caryae.

(19)

' BULLETIN 598, U. S. DEPARTMENT OF AGRICULTURE.

1908. Brirron, W. E. Seventh Report of the State Entomologist of
Connecticut . . . 1907, p. 265-338, 12 pl. New Haven.
Page 332. 4H. caryae.
1908. Gipson, Arthur. An unusual outbreak of Halisidota caterpillars.
In 38th Ann. Rpt. Ent. Soc. Ont. for 1907, p. 82-85, fig. 28-29.
1909. FiercHer, James. Report of the Entomologist and Botanist of
Canada Experimental Farms for 1907-08. 2-+183-213 p.
Ottawa.
Pages 208-209. H. caryae.
1908. Sanperson, E. D. Caterpillars injuring apple foliage in late
summer., N. H. Agr. Exp. Sta. Bul, 189, 205-228 p., 13 figs.
Pages 218, 221. 4H. caryae.

PUBLICATIONS OF THE U. S. DEPARTMENT OF AGRICULTURE
RELATING TO INSECTS INJURIOUS TO DECIDUOUS FRUITS.

AVAILABLE FOR FREE DISTRIBUTION BY THE DEPARTMENT.

Important Insecticides. (Farmers’ Bulletin 127.)

Spraying Peackes for the Control of Brown Rot, Seab, and Curculio. (Farmers’
Bulletin 440.)

The San Jose Secale and Its Control. (Farmers’ Bulletin 650.)

The Apple-Tree Tent Caterpillar. (Farmers’ Bulletin 662.)

‘he Round-headed Apple-tree Borer. (I'armers’ Bulletin 675.) f

The Rose Chafer: A Destructive Garden and Vineyard Pest. (Farmers’ Bul-
letin 721.)

The Leaf Blister Mite of Pear and Apple. (Farmers’ Bulletin 722.)

Oyster-shell Scale and Scurfy Seale. (Farmers’ Bulletin 723.)

Orchard Barkbeetles and Pinhole Borers, and How to Control Them. (Farmers’
Bulletin 763.)

Aphids Injurious to Orchard Fruits, Currant, Gooseberry, and Grape. (Iarmers’
Bulletin 804.)

Control of Codling Moth in Pecos Valley, N. Mex. (Department Bulletin 88.)

Wainut Aphides in California. (Department Bulletin 100.)

‘he Life History and Habits of the Pear Thrips in California. (Department
Bulletin 173.)

Studies of the Codling Moth in the Central Appalachian Region. (Department
Bulletin 189.)

Apple Maggot or Railroad Worm. (Entomology Circular 101.)

How to Control the Pear Thrips. (Entomology Circular 131.)

FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS, GOVERNMENT PRINTING
OFFICE, WASHINGTON, D. C.

Grape Leafhopper in Lake Erie Valley. (Department Bulletin 19.) Price, 10
cents.

The Lesser Bud-moth. (Department Bulletin 113.) Price, 5 cents.

Homemade Lime-sulphur Concentrate. (Department Bulletin 197.) 1915.
Price, 5 cents.

Food Plants of the Gipsy Moth in America. (Department Bulletin 250.) 1915.
Price, 10 cents. .

Life History of the Codling Moth in Maine. (Department Bulletin 252.) 1915.
Price, 10 cents.

American Plum Borer. (Department Bulletin 261.) 1915. Price, 5 cents.

The Parandra Borer. (Department Bulletin 262.) 1915. Price, 5 cents.

The Dock False-worm: An Apple Pest. (Department Bulletin 265.) Price, 10
cents.

Dispersion of Gipsy Moth Larve by the Wind. (Department Bulletin 273.)
1915. Price, 15 cents.

Miscellaneous Insecticide Pavese atone, (Department Bulletin 278.) 1915.
Price, 10 cents.

The Terrapin Seale: An Important Teece Enemy of Peach Orchards. (Depart-
ment Bulletin 351.) Price, 15 cents.

The Cherry Leaf-beetle: A Periodically Impor tant Enemy of Cherries. (De-
partment Bulletin 352.) Price, 10 cents.

The Grape Leaf-folder. (Department Bulletin 419.) Price, 5 cents.

_ The Pear Leaf-worm. (Department Bulletin 438.) Price, 5 cents.

Vear-tree Psylla. (Entomology Circular 7.) 1895. Price, 5 cents,

Canker-worms. (Entemology Circular 9.) 1895. Price. 5 cents.

Woolly Aphis of Apple. (Entomology Circular 20.) 1897. Price, 5 cents,

Buffalo Tree-hopper. (Entomology Circular 23.) 1897. Price, 5 cents.

Pear-Slug. (Entomology Circular 26.) 1897. Price, 5 cents.

The Apple Leaf-sewer. (Department Bulletin 435.) Price, 5 cents.

Boxelder Plant-bug. (Entomology Circular 28.) 1898. Price, 5 cents.

Fruit-tree Bark-beetle. (Entomology Circular 29.) 1898. Price, 5 cents.

Larger Apple-tree Borers. (Entomology Circular 32.) 1898. Price, 5 cents.

15

16 BULLETIN 598, U. S. DEPARTMENT OF AGRICULTURE.

Peach-tree Borer. (Entomology Circular 54.) 1903. Price, 5 cents.
Plum Curculio. (Entomology Circular 73.) 1906. Price, 5 cents.
Aphides Affecting Apple. (Entomology Circular 81.) 1907. Price, 5 cents.
Nut Weevils. (Entomology Circular 99.) 1908. Price, 5 cents. .
‘Nwo Destructive Texas Ants. (Entomology Circular 148.) 1912. Frice, 5
cents.
Mediterranean Fruit Fly. (Entomology Circular 160.) 1912. Price, 5 cents.
San Jose or Chinese Secale. (Entomology Bulletin 62.) 1906. Price, 25 cents. ©
Pecan Cigar Case-bearer. (Entomology Bulletin 64, Pt. X.) 1910. Price, 5-
cents.
Spring Canker-worm. (Entomology Bulletin 68, Pt. II.) 1907. Price, 5 cents,
Trumpet Leaf-miner of Apple. (Entomology Bulletin 68, Pt. III.) 1907. Price,
5 cents.
Lesser Peach Borer. (Entomology Bulletin 68, Pt. IV.) 1907. Price, 5 cents.
Lesser Apple Worm. (Entomology Bulletin 68, Pt. V.) 1908. Price, 5 cents.
Demonstration Spraying for Codling Moth. (Entomology Bulletin 68, Pt. VII.) 4
1908. Price, 5 cents.
Grape-leaf Skeletonizer. (Entomology Bulletin 68, Pt. VIII.) Price, 5 cents.
Peach-tree Barkbeetle. (Entomology Bulletin 68, Pt. IX.) 1909. Price, 5 cents.
Periodical Cicada. (Entomology Bulletin 71.) 1907. Price, 40 cents.
Codling Moth in the Ozarks. (Entomology Bulletin 80, Pt. I.) 1909. Price, 10
cents. :
Cigar Case-bearer. (Entomology Bulletin 80, Pt. II.) 1809. Price, 10 cents. —
Additional Observations on the Lesser Apple Worm. (Entomology Bulletin 80,
Pt. III.) 1909. Price, 5 cents.
On Nut-feeding Habits of Codling Moth. (Entomology Bulletin 80, Pt. V.)
1910. Price, 5 cents. :
Life History of Codling Moth in Northwestern Pennsylvania. (Entomology —
Bulletin 80, Pt. VI.) 1910. Price, 10 cents. ear
Fumigation of Apples for San Jose Scale. (Entomology Bulletin 84.) 1909. ©
Price, 20 cents.
Grape Root-worm, with Especial Reference to Investigations in Erie Grape
Belt. 1907-1909. (Entomology Bulletin 89.) 1910. Price, 20 cents.
Life History of Codling Moth and Its Control on Pears in California. (Ento- —
mology Bulletin 97, Pt. Il.) 1911. Price, 10 cents.
Vineyard Spraying Experiments Against Rose-chafer in Lake Erie Valley.
(Entomology Bulletin 97, Pt. III.) 1911. Price, 5 cents.
California Peach Borer. (Entomology Bulletin 97, Pt. IV.) 1911. Price, 10
cents.
Notes on Peach and Plum Slug. (Entomology Bulletin 97, Pt. V.) 1911. —
Price, 5 cents. -
Notes on Peach Bud Mite. Enemy of Peach Nursery Stock. (Entomology
Bulletin 97, Pt. VI.) 1912. Price, 10 cents. 4
Grape Seale. (Entomology Bulletin 97, Pt. VII.) 1912. Price, 5 cents.
Plum Curculio. (Entemology Bulletin 103.) 1912. Price, 50 cents.
Life-history Studies on Codling Moth in Michigan. (Entomology Bulletin 115,
Ptol.) 1912) Price, 15. cents. 7
One-spray Method in Control of Codling Moth and Plum Curculio. (Ento-
mology Bulletin 115, Pt. II.) 1912. Price, 5 cents. :
Life History of Codling Moth in Santa Clara Valley of California. (Hnto- ©
mology Bulletin 115, Pt. III.) 1913. Price, 10 cents. ;
Grape-berry Moth. (Entomology Bulletin 116, Pt. II.) 1912. Price, i5 cents. —
Cherry Fruit Sawfly. (Entomology Bulletin 116, Pt. III.) 19138. Price, 5
cents.
Lime-sulphur as Stomach Poison for Insects. (Entomology Bulletin 116, Pt.
IV.) 19138. Price, 5 cents. -
Fruit-tree Leaf-roller. (Entomology Bulletin 116, Pt. V.) 1918. Price, 10
cents. 3
Insects Injurious in Cranberry Culture. (Farmers’ Bulletin 178.) 1903. Price,
5 cents. F
Spraying for Apple Diseases and Codling Moth in the Ozarks. (Farmers’
Bulletin 283.) 1907. Price, 5 cents.
Danger of General Spread of Gipsy and Brown-tail Moths Through Imported
Nursery Stock. (Farmers’ Bulletin 453.) Price, 5 cents.
More Important Insect and Fungous Enemies of Fruit and Foliage of Apple. E
(Farmers’ Bulletin 492.) Price, 5 cents.

WASHINGTON : GOVERNMENT PRINTING OFFICE ; 1917

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