Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. SN he ay “AND INSECTICIDES, L. THE PEAR THRIPS. oe ‘By DUDLEY MOULTON, Engaged in Deciduous Fruit Insect Investigations. Il. THE SPRING CANKER-WORM. By A. L. QUAINTANCE, In Charge of Deciduous Fruit Insect Investigations. Il. THE TRUMPET LEAF-MINER OF THE APPLE. _ By A. L. QUAINTANCE, In Charge of Deciduous Fruit Insect Investigations. IVY. THE LESSER PEACH BORER. By A. A. GIRAULT, Engaged in Deciduous Fruit Insect Investigations. V. THE LESSER APPLE WORM. > ‘By A? L. QUAINTANCE, In Charge of Deciduous Fruit Insect Invescigations. YL. GRAPE ROOT-WORM INVESTIGATIONS IN 1907. Be FRED JOHNSON , Engaged in Deciduous Fruit Insect Investigations. we eealpcs are, ea FOR THE CODLING tie 4 ae —— 24 VII. THE GRAPE. LEAR SKELETONIZER, _ ~By P.R. JONES, Engaged in Deciduous Fruit Insect Investigations. 1X. THE PEACH-TREE BARKBEETLE. o By: H. F. WILSON, Engaged in Deciduous Fruit Insect Envestigations, ina =< MINS WASHINGTON: 2 GOVERNMENT PRINTING OFFIOR. 1909. «oe U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY— BULLETIN No. 68. L. O. HOWARD, Entomologist and Chief of Bureau. PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES. I. THE PEAR THRIPS. By DUDLEY MOULTON, Engaged in Deciduous Fruit Insect Investigations. I. THE SPRING CANKER-WORM. By A. L. QUAINTANCE, In Charge of Deciduous Fruit Insect Investigations. Hl. THE TRUMPET LEAF-MINER OF THE APPLE. By A. L. QUAINTANCE, In Charge of Deciduous Fruit Insect Investigations. IV. THE LESSER PEACH BORER. By A. A. GIRAULT, Engaged in Deciduous Fruit Insect Investigations. V. THE LESSER APPLE WORM. By A. L. QUAINTANCE, In Charge of Deciduous Fruit Insect Invesiigations. VI. GRAPE ROOT-WORM INVESTIGATIONS IN 1907. By FRED JOHNSON, Engaged in Deciduous Fruit Insect Investigations. VIL. DEMONSTRATION SPRAYING FOR THE CODLING MOTH. By A. L. QUAINTANCE, S. W. FOSTER, FRED JOHNSON, and A. A. GIRAULT. Vl. THE GRAPE-LEAF SKELETONIZER. By P.R. JONES, Engaged in Deciduous Fruit Insect Investigations. IX. THE PEACH-TREE BARKBEETLE. By H. F. WILSON, Engaged in Deciduous Fruit Insect Investigations. & wv pm SH = evs ae Sete as SN We: = sas BA ies ae eV qe SS SS SS + ——— 1 NAS BEB Sn Se A BE CSA ere << =e, os, ~ Tian
|
| thrips; 6, branching mycelia; c, forming only avery. small percentage of ants > ||
: ee Roe ee ge ® © highly were actually killing thrips. Four |
hundred ants were examined as
| they descended a thrips-infested tree. Twelve of these carried
| something in their jaws and only 4 of these objects were thrips. Thus —
I only 1 per cent of the ants on the tree were actually killing thrips —
| and carrying them down. It has been a common observation among —
orchardists, however, that thrips are not common where ants are ©
| unusually abundant.
Spiders and mites are active enemies of thrips. In some of our —
breeding cages almost all of the thrips would at times be killed by
il some small spider or mite which had gained an entrance. The writer
| has observed ared mite (Rhyncholophus sp., determined by Mr. Nathan —
| Banks) actively engaged in feeding on the onion thrips (Thrips tabaci —
THE PEAR THRIPS. 15
Lind.). Both the thrips and the mite were very common in large onion
fields, covering several hundred acres. A mite would be seen to ap-
proach and grasp a thrips with its front pair of legs and, inserting its
proboscis, suck out the body juices of its prey. A single mite was
often observed thus to kill several thrips within a very few minutes.
The writer strongly suspects that some mite preys on the younger
stages of the pear thrips while it is in the ground. This would be
entirely possible, and mites are commonly found in the grass and in
the ground.
A fungus, presumably parasitic, has been endemic among thrips
during the seasons 1905 and 1906. In its different stages it lives
on both young and mature thrips, and in a way parallels the life of its
host. During the spring of 1905 thrips larve were often observed to
be thickly infesting a tree, and after these had disappeared, presum-
ably having gone into the ground, none or but few living ones could
be found. Many larve, too, seemed to
leave the tree before they ha reached
full growth, and within breeding cages
these larve were seen to die as the
direct result of the parasite. Project-
ing from their bodies were to be seen
the tiny fruiting conidiophores of the
fungus. Adult thrips were seen to be
attacked by another form of the para-
site during the spring of 1906. The
past two seasons have offered almost
ideal conditions for the development
of the fungus, enabling it to become
quite widespread. Fic. 8.—a, Resting spores of a fungus
The life history of the fungus has found within dead thrips larva, much
been determined only in part. The at oe ae
heavy-walled resting spores, the dor-
mant stage, are found within larve and adults in the ground; never,
thus far, in pup in the ground or in individuals on the tree. Dead
larve from the ground show that the internal body organs have all
been displaced by the fungus, and in most cases the body contains
only a mass of the heavy-walled spores. The transition which takes
place in the formation of these spores is as yet not clear, but there
seems to be a general breaking up of the fungus hyphx within the
thrips’ body. In one well-prepared specimen there was an indistinct
grouping of particles around many centers. These were presumably
the forming spores, for in the next stage the formation of such spores
was complete. These heavy-walled spores may be found nearly the
whole year through, although they are especially abundant from May
until the following February.
16 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
In the conidiophore stage on the tree the fungus hyphe break forth
in groups from between the body segments and extend out as long
slender threads, which in turn branch and form numerous fruiting
organs. This stage of the fungus has been taken only from adult
thrips on the tree and not from the larve, and it has been found
present almost everywhere that the pear thrips has been collected.
There is no doubt that the fungus spends a part of its life on the tree
and a part in the ground, the rapidly fruiting stage among the active
thrips and the heavy-walled dormant stage within the hibernating
individuals in the ground; but we can only surmise how it is carried
from one to the other. The bodies of the larval thrips within the
eround are all absorbed by the fungus and naturally, therefore, the
spores must be carried to a new host before they can germinate to
any great extent. We have found adult thrips in the ground whose
dead bodies contained only a few spores and others which developed
some of the external mycelial growth within their cells. If this were
often the case, and these individuals in the ground produced fruiting
spores as they do on the trees, it would be an easy matter for healthy
individuals in coming from the ground to become accidentally infested
and to carry the parasite up to the tree where, because of the gre-
garious habits of the insect, it would spread rapidly.
The fungus grows readily in the nutrient agar under ordinary con-
ditions and seems to retain its virulence and can be transferred from
cultures to the living thrips. The fungus may prove to be a check
for the pear thrips, but its effectiveness is uncertain because it is so
subject to climatic conditions.
Wier s) >on Pres —
2 4
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ae.
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Dw agian er piak
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U.S. D. A., B. E. Bul. 68, Part IT. ‘ D. F. I. L, July 6, 1907.
PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
THE SPRING CANKER-WORM.
(Paleacrita vernata Peck.)
By A. L. QUAINTANCE,
In Charge of Deciduous Fruit Insect Investigations.
INTRODUCTION.
Two species of canker-worms in the United States, the spring
eanker-worm (Paleacrita vernata Peck) and the fall canker-worm
(Alsophila pometaria Harr.), are often very troublesome pests in
apple orchards, infesting also the elm, cherry, and, to a less degree, a
few other trees. These insects, though widely distributed, usually
occur in injurious numbers quite locally, infesting often but one or
two orchards in a neighborhood where conditions have been favorable
for their development. The females of both species are wingless,
hence their dissemination is very slow. The insects are doubtless
distributed mostly on nursery stock in the egg stage, or locally the
larve and moths may cling to clothing of persons, or may be dis-
tributed by teams visiting the infested orchards.
Old orchards which hae been in sod or have not been cultivated
for many years and which are not sprayed with arsenicals furnish
‘ideal conditions for the multiplication of canker-worms when the
latter are once established. Frequently such orchards are defoliated
each spring, with the result that the injury to the trees prevents the
formation of fruit buds, and after a few years of such injury the
trees will begin to die. While certain weather conditions and the
natural enemies of canker-worms may often greatly reduce the num-
ber of these insects, energetic steps on the part of the orchardist are
usually necessary to insure the complete destruction of the pests and
to permit the trees to resume their normal fruit production. In the
great majority of cases, if not in all, canker-worms are practically
limited to orchards which are neglected as to spraying and cultiva-
tion, either practice usually serving to keep them so reduced in num-
bers that their injuries are inconsequential.
17
18 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
Complaints of both fall and spring canker-worms are frequently
received by the Bureau of Entomology. Correspondents often report
that they are unable to protect their trees by the use of arsenicals, and
the opinion has at times been expressed that these insects can not be
destroyed by arsenical sprays. While it has often been stated in the
literature on canker-worms that they are more resistant to poisons
than many other species of insects, yet there is no doubt that they
may be readily killed by thorough use of poisons. In most cases the
poor results from spraying are evidently due to failure to make thor-
ough applications of the spray, the large size of the trees and the
unfamiliarity of the orchardist with spraying operations often con-
tributing to this end.
In the present brief article the life history and habits of the spring
canker-worm are given, together with results of practical work in its
control. The hfe history and habits of the fall canker-worm prac-
tically parallel those of the spring species, except that the great
majority of the moths of the former species emerge and oviposit in
the fall. The operations of spraying and plowing herein discussed
will be equally effective in its control.
LIFE HISTORY AND HABITS.
There is but one generation of canker-worms each year. After
obtaining their growth on the trees in the spring, the larvee enter the
soil to a depth of from 2 to 5 inches, and after making an earthen
cell transform to pupe (see Pl. III, fig. 3), in which condition they
remain until the following spring. Early in the spring, or even
during warm spells in winter, the pupe transform to moths, which
make their escape from the soil and go to the trees. The males are
winged, as shown in Plate III, figure 5, but the females are destitute
of wings, as illustrated in Plate III, figure 4. In ovipositing the
females climb the trees and place their eggs in irregular masses under
loose bark scales, in cracks in the bark, in crotches of limbs, etc., as
shown in Plate III, figure 1, which illustrates an egg mass which was
placed on the underside of a bark scale. The number of eggs in an
individual mass varies greatly. Females taken presumably before
oviposition had begun deposited eggs in confinement, the number to a
mass varying from 17 to 119, with an average for 12 masses of 47.
An individual egg is elongate-elliptical in outline, somewhat
resembling a hen’s egg in miniature. The average dimensions of ten
recently deposited eggs were found to be 0.69 by 0.42 mm. When
first deposited the surface is shining, pearly white, but in the course of
a few hours the egg takes on a yellowish-green color, in certain lights
showing a golden, greenish, or purplish iridescence. As the embryo
approaches maturity it becomes very evident and lies curled around
just within the shell, its cephalic and caudal ends together, the egg-
Bul, 68, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE Ill.
STAGES AND WoRK OF SPRING CANKER-WORM (PALEACRITA VERNATA PECK).
Fig. 2.—The larve or canker-worms. Fig. 3.—Pupe.
Fig. 6.—Work of canker-worms on apple
Fig. 7.—Later work of the larvae, only the midribs of leaves being
left. Figs. 1-5, considerably enlarged; tigs. 6, 7, reduced. (Original.)
Fig. 1.—Egg mass on bark scale.
Fig. 4.—Female moths. Fig. 5.—Male moth.
leaves when small.
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THE SPRING CANKER-WORM. 19
shell becoming more or less concave centrally. Shortly before hatch--
ing the eggs become quite dark, due to the color of the larva within.
Eggs secured from females in confinement on the nights of March
8, 10, and 12, and kept under out-of-door conditions in the insec-
tary yard at the Department of Agriculture, Washington, D. C..
were hatching April 10, 11, and 14, respectively, giving for this stage
a fairly uniform period of thirty-two to thirty-three days. The
effect of warm weather upon the development of the embryo may be
judged from the fact that eggs kept in the insectary at a temperature
of 65 to 70° F. hatched in about eleven and one-half days.
When just hatched the spring canker-worm is quite small, measur-
ing but 1.25 to 1.5 mm. in length, varying with the extension of the
body. The head is about 0.25 mm. wide, which slightly exceeds the
width of body across thoracic segments. The head and shield are
shining black, and the body above dark olive-green, with a distinct
central longitudinal white stripe centered with narrow interrupted
lines of the same color as the body. Along each side is a wide irregu-
lar white stripe, including the spiracles and adjacent tubercles.
Below, the body is dark yellowish or brownish in color. The thoracic
legs are stout and dusky exteriorly. There is a single pair of pro-
legs on the sixth abdominal segment and a pair of anal prolegs.
The larve come from the eggs about the time the leaves of the
apple are pushing out, and the latter are at once attacked. At first
only small holes are eaten through the leaves, but later, as the larve
grow, the entire leaf substance save the midrib is devoured. (See
ma. AIT, fios. 6, 7.)
After three or four weeks of feeding, the time varying much with
the temperature, the larve have become full grown. They then meas-
ure from 18 to 23 mm. (0.7 to 0.9 inch) in length. Considerable
color variation is likely to occur, some specimens being ash-gray,
green, or yellow, but the predominating color is dark greenish olive
or blackish. There are two pale narrow lines down the back, centered
with a broader dark stripe and a whitish stripe along each side.
(See Pl. III, fig. 2.) The larva of this species is readily distin-
guished from that of the fall canker-worm by the fact that the former
has but two pairs of prolegs, while the latter has three, the first pair,
however, on the fifth abdominal segment, being more or less reduced.
Newly hatched larve placed on apple trees under a large wire
cage in the insectary yard April 12, 1905, had matured and were
entering the ground for pupation by May &, and by May 11 all had
disappeared from the trees. This gives twenty-seven to thirty days
for the larval existence. The egg and larval stages together require
some two months, and the remainder of the year, except the time
spent in the adult condition before ovipositing, is passed in the pupal
stage in the soil. As has been stated, the insect pupates from about
20 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
2 to 5 inches below the surface of the ground and may be readily
destroyed by thorough plowing and cultivation during the summer
and fall.
DEMONSTRATION WORK IN CANKER-WORM CONTROL.
For several years the spring canker-worm has been quite trouble-
some in a few old orchards in northern Virginia and very little head-
way had been made by the owners of the orchards in its control. In
the spring of 1905 Dr. John S. Lupton, of Winchester, Va., desired
the assistance of the Bureau of Entomology in freeing from this pest
his large orchard of 30-year-old Newton pippin trees, which had been
defoliated to a greater or less extent for three or four seasons. The
orchard had been in sod for years and no recent spraying had
been done for the coding moth. Under these conditions the canker-
worms had been able to multiply with practically no interfer-
ence and had become exceedingly abundant, 50 per cent of the trees
being practically defoliated and the others more or less so. A plan
of treatment was submitted to Doctor Lupton, which was carried out
by him under the writer’s supervision. This treatment consisted in
a thorough spraying of the orchard with Paris green at the rate of
1 pound to 75 gallons of water (plenty of lime being added to lessen
danger of injury to the foliage), the thorough plowing of the orchard
during the early summer, and its subsequent cultivation during that
season. Only one application of poison was made, and not until ~
much later than was desirable, the larve being already from one-half —
to three-fourths grown, many trees having been practically defoliated. —
Nevertheless, the treatment checked further defoliation and within two
to three days the larve had largely disappeared. That the majority
were poisoned was evident, since upon later examinations pup were —
exceedingly scarce, even under trees from which the leaves had been
i almost stripped. During early August the orchard was thoroughly
plowed, special: pains being taken to break up the soil under the
ih trees. Late in the fall the worst infested portion of the orchard was |
iF again plowed, and at right angles to the direction followed in the
iit first plowing. The rest was plowed early the following spring, the
HII whole being prepared for corn, which later was planted, receiving
necessary cultivation during 1906. As was quite evident in the spring —
| of 1906, the thorough spraying with Paris green and plowing of the
i orchard had destroyed the great majority of the insects. In the early
Hi spring of 1906 bands of a sticky preparation placed around the —
iH trunks of trees which had been practically defoliated in 1905 caught —
\ - not more than two dozen specimens of adults in all, and larvee were —
very difficult to find later. That the absence of the insects in this
Mi orchard is to be attributed solely to the spraying and plowing and —
| not to unfavorable weather conditions or the influence of parasitic
Bul. 68, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE IV.
TREES DEFOLIATED BY SPRING CANKER-WORMS AND EFFECTS OF TREATMENTS.
Fig. 1.—Defoliated trees in Lupton orchard. Fig. 2.—The same treesa year later. Fig. 3.—Defo-
liated trees in the Purcell orchard. Fig. 4.—An adjacent row of trees protected by two appli-
cations of arsenate of lead. (Original.
eT ree ee ee SS — OOO e™
9
THE SPRING CANKER-WORM. 91
and predaceous enemies is evident from the fact that in a near-by
orchard, untreated, the insects were excessively numerous, completely
defoliating the trees during the spring of 1906. Figure 1, Plate IV,
is from a photograph of trees in the worst infested portion of the
Lupton orchard in 1905, and shows the injury that had been done
before the application of the Paris green spray. The condition of
these same trees, but looking in another direction, on June 9, 1906, is
shown in figure 2.
During the spring of 1906 spraying work against canker-worms
was also carried out in another orchard near Winchester consisting
of 30 acres of 35-year-old Baldwin trees. This orchard also had been
entirely neglected as to plowing and spraying for many years past,
and for some years most of the trees had been completely defoliated
by the spring canker-worm, some of them and portions of others
being dead. Arrangements were made to spray a portion of the
orchard, though it was not considered practicable by the owner to
have the ground plowed. Arsenate of lead was used as a poison and
applied at the rate of 3 and 5 pounds per 50 gallons of water for the
first and second applications, respectively. At the time of the first
application the leaves were well out, being from three-fourths of an
inch to an inch in diameter. The canker-worms had almost all
hatched, very many being in the second stage, and were literally
swarming over the trees. The second application was made May 5,
most of the larve at this time being from’one-half to three-fourths
grown, the untreated trees being already nearly bare of leaves. The
treated trees, while showing some injury from the larvee, especially
in the higher parts, were in almost full foliage, though subject to
infestation from adjacent trees. The second application largely pro-
tected the trees from further injury, and there is no doubt that if the
entire orchard had been treated the insects would have been practi-
cally exterminated. Figure 3, Plate IV, shows the defoliated condi-
tion of untreated trees June 9, after the larve had all disappeared,
and the condition of sprayed trees in an adjacent row is shown in
figure 4 on the same plate.
RECOMMENDATIONS.
Orchardists having canker-worms to contend with may confidently
expect to practically eradicate them in the course of one or two sea-
sons by following the methods above described, namely, thoroughly
spraying the trees with a strong arsenical and thoroughly plowing
the ground during the summer. If Paris green is used, this should
be applied at the rate of 1 pound for each 100 gallons of water, and
unless used in Bordeaux mixture there should always be added the
milk of lime made from slaking 4 or 5 pounds of good stone lime.
Arsenate of lead may be used at the rate of 6 to 10 pounds to 100
72 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
gallons of water or Bordeaux mixture, and because of the strength
at which it may be used without injury to foliage and its excellent
sticking qualities it is to be preferred to other arsenicals for canker-
worms. At least two applications of the poisoned spray should be
made; the first as the fruit buds are exposed, or just as the foliage is
pushing out, but before the blossoms open, and the second in eight to
ten days, or at once after the blossoms have fallen. In bearing
orchards the second treatment is the principal one for the codling
moth, and if the poison be used in Bordeaux mixture the two applica-
tions of this combined insecticide and fungicide will largely protect
the trees and fruit from canker-worms, the codling moth, and other
leaf-feeding insects, and will lessen apple scab.
While it may often appear impracticable to spray some oreharee on
account of the height of the trees, most orchards may be plowed and
cultivated, and this work should certainly form a part of the plan of
canker-worm eradication.
Another important method of protecting high orchard and other
trees which it is impracticable to spray is the employment of special
protectors, such as bands of cotton, or sticky substances. These are
placed around the trunk of the tree near the base, and are used to pre-
vent the ascent of the wingless females to deposit their eggs, or the
ascent of any larve from eggs deposited below the bands or which
have fallen from the trees. Sticky substances, such as printer’s ink, -
tar, bird lime, and certain proprietary preparations, are best. On
account of the danger of injury to the trees, these are best applied on
strips of paper 5 or 6 inches wide and of sufficient length to go around
the tree. The loose bark should first be scraped from the trunk where
the band is to be applied, and if a light band of cotton batting be
first fastened where the paper band is to be placed this. will effectu-
ally prevent the insects working up beneath the sticky paper band.
Cotton batting may also be used, the trunk being encircled with a
strip 4 or 5 inches wide. This is tied with a string at the lower edge
and the band then turned downward. This will be effective so long —
as it remains fluffy, but usually requires renewal after heavy rains.
Whatever form of protector is used must be applied quite early in the ©
spring, at least six or eight weeks before the apple buds are due to —
burst, as the moths come out very early, sometimes even during ©
warm spells in the winter.
The methods of control given above are equally applicable to thea %
fall canker-worm, except that in the use of bands to prevent ie
ascent of moths these must be applied in early fall, since the moths om”
this species oviposit mostly during that season.
mes. . AL, B: b Bul..68, Part. ITT. D. F. I. I., October 15, 1907.
PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
THE TRUMPET LEAF-MINER OF THE APPLE.
(Tischeria malifoliella Clemens. )
By A. L. QUAINTANCE,
In Charge of Deciduous Fruit Insect Investigations.
During 1905 this species became unusually abundant in the Dis-
trict of Columbia and in localities in adjacent States. Specimens
of mined apple leaves were received from Afton, Va., Newark and
~ Woodside, Del., Cheltenham, Pa., and Vermont. Judging from the
- condition of the leaves sent, the insect in these several places was
much less abundant, however, than in the immediate vicinity of
~ Washington. During 1906 the insect was again exceedingly abun-
|
:
en ee ee eee
— dant in the environs of Washington, was the subject of further com-
plaint from Delaware, and was received from Connecticut.
HISTORY.
This species was described in 1860 by Clemens in the Proceedings
of the Philadelphia Academy of Sciences, Volume XII, page 208.
_ from material presumably from Pennsylvania. Interesting observa-
_ tions concerning its food plants are presented by Chambers in the
— Canadian Entomologist, Volume III (1871), page 208; Volume V
(1878), page 50, and Volume VI (1874), page 150. Additional notes
are given by him in the Cincinnati Quarterly Journal of Science,
~ Volume IT (1875), page 3; in Bulletin U. S. Geological and Geo-
) graphical Survey, Volume IV (1878), page 107, “ Tineina and their
~ Food Plants,” and in Psyche, Volume IIT (1889), page 68. Messrs.
Frey and Boll, in Stettiner Entomologische Zeitung, Volume
XXXIV, page 222, note its occurrence in Germany on apple im-
ported from this country. The insect has been occasionally men-
tioned by Lintner in the reports of the New York State Entomolo-
gist and elsewhere, and is the subject of an article with bibliography
in his Eleventh Report. Dr. E. A. Brunn, in the Second Report of
the Entomological Department of Cornell University (1882), in a
.“
-o
24 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
paper on the Tineide infesting the apple trees at Ithaca, N. Y.,
gives an account of the insect with figures of moth, larva, and mines
in apple leaf. A more extended account is given by Dr. C. M. Weed
in the Fifteenth Report of the Illinois State Entomologist (1889),
pages 45-50; and it is mentioned by Lugger in Minnesota Experiment —
Station Bulletin 61 (1898), page 316, and later (1903), by Wash-
burn, in Minnesota Bulletin 84, page 66. In Bulletin 180 of the ~
Michigan Experiment Station (1900), ee 125, and Special Bulletin |
24 of the same institution (1904), page 22, the species is the subject —
of short illustrated articles by Pettit; and it is also discussed by ©
Lowe in Bulletin No. 180 of the New York Agricultural Experiment |
Station (1900), page 134. In 1906 brief mention is made by C. P. ©
Close of the occurrence of this species in central Delaware (Bul. 73, ©
Delaware College Agric. Exp. Station, p. 18), where it is said to have ©
been increasing for several years past.
The above includes the important references to this species so far —
as the writer has been able to determine.*
DESCRIPTIVE.
The mine.—The mines occur exclusively on the upper surface of |
leaves, beginning at the point of deposition of the egg as a narrow, —
often curved line, gradually or suddenly enlarging in isolated and |
typical examples, and finally having the outline of a trumpet or
mussel shell (see Pl. V). Completed mines vary much in shape and —
size, but will average, perhaps, in the more typical examples one-half _
inch long by one-fourth inch wide. There is considerable irregu-
larity in the feeding habits of the larve, and blotch mines are often —
produced, the narrow linear portion being frequently more or less—
obliterated. In many mines crescent-shaped patches of white cross
the linear portion, extending often well into the body of the mine. 2 |
Unless held to the light the mine is scarcely noticeable from the lower 2 |
surface of apple leaf, but above the blistered epidermis varies in _
color from whitish to dark brown, and the spotted appearance of
badly infested leaves is noticeable some distance from the trees. _
Injury is confined principally to the palisade layer of cells immedi- _
ately below the epidermis of the upper surface of the leaf. The posi- _
tion of the mine on the leaf is quite variable, but it does not usually |
cross the larger veinlets, extending more or GS parallel with them. ie
The egg—The eggs of Tischeria malifoliella are regularly ellip- _
{ical in outline, somewhat convex centrally, but flattened around the —
mar rgin, which area is more or less wrinkled. When first laid they
«Since this article was prepared this species has been well treated by Mr
C. D. Jarvis, in Bulletin 45 of the Storrs, Connecticut, agricultural experiment
station. an |
.
!
- flat, with the segments
ts
ond or third segment,
the last three segments
rounder and narrower
‘than the preceding.
THE TRUMPET LEAF-MINER OF THE APPLE. 25
are greenish yellow in color and somewhat translucent. In some
lights they are irridescent, as are the empty egg shells. One or two
days previous to hatching they become comparatively conspicuous,
the embryo being central and the whitish margin showing plainly
against the dark color of the leaf. The empty shells are white and
mark the beginning of the mine. The average size (based on meas-
urements of five eggs) is 0.34 mm. by 0.54 mm. The eggs are at-
tached closely to the leaf, usually in furrows along a veinlet, but
occur more or less promiscuously. This stage has not previously been.
described.
The larva—tThe larva (fig. 9, ¢) upon hatcning measures about
0.7 mm. in length. The head is brownish, the rest of the body whit-
ish, except cervical and anal shields, which are dusky. Full-grown
—larve will average 5 mm. in length by 1 mm. in width across the
third thoracic segment. The head is about 0.5 mm. wide, retractile,'
bilobed, brownish or even black in color. The general color of the
body is light green, ex-
cept cervical and anal
shields, which are
brownish. The body is
Yi
Ny Yj
i
fi)
Mes
: Ih
My ite
} ?
Wr
7
very distinct, and taper-
ing caudad from the sec-
Fic. 9.—Trumpet leaf-miner of the apple (Tischeria malifo-
é : liella): Adult, larva, pupa, details.
Thoracic segments with
three long sete on each side; succeeding segments with two setz on
each side varying considerably in length; at caudal end there are
humerous shorter curved setw. Thoracic legs absent. Abdominal
and anal legs marked by five pairs of crochets (see fig. 9, c, d).
The pupa.—The pupa is rather variable in size, the average of five
being 3.35 mm. by 0.95 mm. The color when first formed is rather
uniformly pea green, later becoming much darker, varying with age.
The general color of the thoracic region and head is dark brown to
blackish. The abdomen is dark green, yellowish caudad; the caudal
margin of the rather distinct segments is brown. Leg and wing
sheaths free; tip of third pair of legs reaching to cephalic border of
third segment from last. The antennal sheaths reach the cephalic
margin of the fifth segment from last. The spiracles are on slight
conical elevations, and on each side of abdomen, ventrad of spiracles,
isa row of long slender seta, a pair to each segment. Cremaster of
two stout short projections, slightly curved at tip. Head obtusely
si 10090—Bull. 68—09——3
26 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
rounded, without horn-lke processes, but with a pair of slender
sete. This stage has not hitherto been described, the description _
given by Weed being evidently that of the pupa of some other
species. (See fig. 9, e, 7.) |
The adult or moth—The description given by Clemens is as fol-
lows: “ The head and antenne shining, dark brown, face ocherous.
Fore wings uniform, shining, dark brown with a purplish tinge, —
slightly dusted with pale ocherous; cilia of the general hue. Hind ©
wings dark gray; cilia with a rufous tinge.” (See fig. 9, a, 0.)
FOOD PLANTS.
In his original description Clemens gives the food plant as apple. -
Chambers states that he bred it from ie es of different species of —
haw (Crategus), sweet-scented crab (Pyrus coronaria), blackberry il
(Rubus villosus) , and raspberry (Rubus occidentalis), and adds that
it probably mines other species of Rosaceee. Later Clemens saya |
that this species, as well as certain others, feeds indifferently on
leaves of Crateegus, Prunus, and Malus. {
In 1873 Messrs. Frey and Boll described 7%scheria enea, bred from | |
Rubus villosus, and Tischeria roseticola from Rosa carolina. Tn the ~
Cincinnati Quarterly Journal of Science Chambers adds tl: a
berry (ubus canadensis) to the food plants of Tischerta mali
and does not consider 7’. enea of Frey and Boll, from blackbe ~§
tinct from 7. malifoliella; he regards as belewenne to this species '
the specimens bred from all the species of abuse Crategus, and —
Pyrus. He also doubts the distinctness of 7’. roseticola. However,
in a later publication, “ Tineina and Their Food Plants,” Mr. Clemens
recognizes the two species of Frey and Boll above Shea, and as food —
lente of 7. malifoliella gives Crategus, Pyrus coronaria, and Pyrus —
malus, omitting as food plants species of Prunus, Rubus, and Rosa,
assigning the two latter as food plants of wnea and roseticola, re- .
spectively. The distinctness of the three species was again recog- 1
nized by Chambers in his Index to the Tineina of the United States
and Canada, ae more recently by Doctor Dyar in his “ List of N. A.
Lepidoptera.” x
Finally Mr. Pettit notes serious damage to blackberries from
T. malifoliella at the South Haven substation in Michigan, and —
states that the insects seem to breed in the neighboring apple trees
and come to the blackberries from them. However, in the absence
of definite breeding work and the critical comparison of adults thus
secured, it will be best to follow the evident conclusions of Chambers
and Dyar, and limit the food plants of 7. malifoliella to species of
Crategus and Pyrus. During the present season (1907) the insect
}
a Bul. 52, U. S. Nat. Museum, 1902.
Bul. 68, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE V.
;
“y
s\*
PA
an
a
¥
5
‘
s
Oe a
WORK OF THE TRUMPET LEAF-MINER OF THE APPLE (TISCHERIA MALIFOLIELLA): LARVAL
MINES IN APPLE LEAF.
b
THE TRUMPET LEAF-MINER OF THE APPLE. 27
was never found on blackberry, though growing in abundance near
infested apple trees.
SEASONAL HISTORY.
But little of a definite character has been recorded concerning the
seasonal history of this species. Clemens states that “ when pupation
begins the leaf is thrown into a fold, which is carpeted with silk, and
_ the pupa les within it. This state begins about the latter part of
September, and the imago appears early in May.” Brunn, who
studied the species at Ithaca, N. Y., says, referring to the mines,
“ Within these clean and comfortable quarters the larva passes the
winter.” The observations of Weed, reported in “Injurious and
Other Insects of Illinois” (1886), agree entirely with those of
Brunn; and Lintner, writing in 1895, says it hibernates within the
leaf in its larval stage. Pettit, in 1900, states that “ The larve are
said to change to the pupal condition during September, and to re-
-mmain in that condition until the following May,” and again, in 1904,
he says, “ The pupal stage is passed in the mines of the leaves, neces-
sarily on the ground in the winter time.” Observations of Lowe in
1900 at Geneva, N. Y., agree with those of Brunn and Weed, though
on October 29 a larva was found evidently about to pupate.
Until 1900 this species was evidently considered single brooded,
_ though no definite observations seem to have been made on this point.
_ During that year Pettit reported for Michigan that full-grown larve
were found about the middle of July and again September 16, indi-
cating at least two generations of larve. August 16, 1905, in Niagara
County, N. Y., the writer found numerous empty mines with pro-
truded pupa cases, and a single live pupa in a mine. Young larve
from eight to ten days old were fairly common, indicating a seeond
generation for that section.
The abundance of the insects in the vicinity of Washington during
the past two years has permitted some observations on this point.
In 1905 the insect was first noticed, May 30, on an isolated apple
tree near the writer’s home in Kalorama Heights, D. C., and this
tree has been kept under observation during the seasons of 1905 and
1906. On May 30, 1905, when first seen, the first generation of
larve was maturing, one pupa being found, and by June 18 the
great majority of larve had pupated, and quite 25 per cent of the
moths had already emerged. ‘The first generation of larve was quite
abundant, almost every leaf having 8 to 10 mines. Practically all
upe had yielded moths by June 30, and the leaves were peppered
ith eggs, many of which had already hatched, the larve being yet
aite small, in linear mines. By July 27 the second generation of
larve had mostly pupated and many moths were out and ovipositing.
’
28 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
The number of mines per leaf at this time averaged from 15 to 18. |
By August 4 pup had largely yielded moths, and eggs were
again very abundant, a few having already hatched. By August 26 —
another generation of moths had developed and their eggs were in ;
an advanced condition of development and many had already hatched. 4
September 10 larve of this, the fourth generation, were of various —
sizes, from quite small to full-grown, but no pup could be found. —
The leaves, although practically covered with the mines on their
upper surfaces, were still hanging on the trees, and there was but
little evidence of serious injury having been done. By October 30
quite 50 per cent of the foliage was on the ground and those leaves
remaining on the trees were more or less rolled in from the edges.
This premature falling of the foliage was undoubtedly due to the
work of the leaf-miner, and this seems to have been its principal
injury. At this time the larve were full-grown and had lined their —
mines with a dense lining of silvery-white silk preparatory to hiber-
nation. Leaves picked from the ground contained from 6 to 15_
larve per leaf. Leaves examined December 6 showed no change of —
condition, no pupe whatever being found, and this condition was also —
found to obtain on January 21. March 12 a quantity of leaves were
collected from the ground, and at this time fully 90 per cent of the ~
larve had transformed to pupeze, though this stage had but recently
been entered, as indicated by the bright-green color. On April 22, —
at which time the fohage of the apple was just pushing out, only
pupz could be found, and some of these were quite dark in color, the ©
inclosed moth evidently being nearly developed and ready to escape.
The formation of pup as just mentioned is perhaps to be regarded
as abnormally early, since the weather about this time was unusually
warm. This belief is strengthened by the fact that in infested apple ©
leaves kept in a breeding cage out of doors in the insectary yard the ©
insects were all in the larval condition, except one pupa, on April
5, the moths mostly emerging the latter part of that month. By May
7 eggs were very abundant on the foliage of the apple tree under
observation, as many as 12 being counted on a single leaf, but on
some leaves none at all were to be seen. At this date no larvee had yet
hatched, though many eggs were in an advanced stage of development,
the embryo being readily seen within the delicate shell when examined |
with a hand lens. By June 24 larve from these eggs had mostly _
matured and had entered the pupal stage, though a few full-grown |
larve were still to be found. The time of maturing of the first —
generation in 1906, therefore, agrees closely with this period in 1905. —
Length of life cycle.-—Eggs deposited during the night of July 31 |
were very generally hatching on the morning of August 8. The-
larva leaves the egg by eating directly through the lower surface at
one end into the leaf beneath, at once beginning its mine, and is thus »
THE TRUMPET LEAF-MINER OF THE APPLE. 29
at no time exposed. The act of leaving the egg is very deliberate,
and may occupy ten or twelve hours before the body is completely
out of the shell and into the mine. Feeding alternates with resting,
the larva often working backwards out of the mine into the egg-
shell, where it may rest for half an hour or more. The mines are
at first but little wider than the width of the insect and are lined with
silk from the start. Progress at first is slow, the larva proceeding
about twice its length during the twenty-four hours following the
breaking of the eggshell. After a few days, however, it feeds much
- more vigorously and soon widens the mine in the course of its feeding.
Of the larve which hatched the morning of August 8, 12 out of the
15 under observation pupated during the night of August 25, this
stage therefore lasting approximately eighteen days; and the moths
from these pupez mostly emerged by the morning of September 2,
one emerging the morning of August 30, making for the life cycle
about thirty-three days. Moths kept in confinement without food
lived for about two days. According to Chambers, the larve molt
five times, and there are no marked differences either in color or
structure between the larve at different stages of growth.
DISTRIBUTION.
The trumpet leaf-miner is evidently a native species, its original
food plants probably being species of Crategus and wild Pyrus. It
has been recorded from New York, Texas, Illinois, and Michigan.
The material on. which Clemens based his description was probably
from Pennsylvania, and the observations of Chambers made in Ken-
tucky indicate its occurrence in that State. Records of this Bureau
show it to occur in South Carolina, Virginia, Delaware, Pennsy!]-
vania, Connecticut, Rhode Island, Vermont, Massachusetts, Missouri,
Arkansas, and Nebraska. and at Ottawa, Canada.
PARASITES.
This miner is freely parasitized. At Ithaca, Dr. Brunn bred from
it Sympiesis lithocolletidis How. and Astichus tischerie How. The
former species has been bred from this insect at Champaign, IIl., by
Weed, and ELlasmus pullatus Howard is doubtfully recorded from
this species from Missouri. At different times during the season of
1905, at Washington, D. C., infested apple leaves were placed in jars,
and the following species were secured, some of which probably are
secondary parasites: Urogaster tischerie Ashm., Sympiesis nigro-
femora Ashm., Horismenus popenoct Ashin., Closterocerus trifasciatus
Westw., Hulophus n. sp., Zagrammosoma multilineata Ashm., and a
variety of this species. A species near Phygadeuon was reared, and
one near, if not identical with, C?rrospilus flavicinctus Riley.
30 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
TREATMENT.
When excessively abundant, as has been the case in several localities -
during the past two or three years, the injury done by the larve in |
the leaves will cause many of these to fall prematurely, interfering —
with the proper development of the fruit and the health of the tree,
and its control, therefore, becomes a matter of importance. This
can perhaps best be accomplished by plowing the orchard in the ~
spring, covering as much as possible all fallen leaves and trash, as in —
the former the larvee pass the winter, and it is practically certain that
the moths will not be able to make their escape from the soil. This
work should be done not later than the blooming period of the trees,
to insure covering up the infested leaves before any early-emerging
moths escape. As this method of control involves no extra labor. —
not requisite in proper orchard treatment, this species, which has but
recently attracted attention as a pest of the apple orchards, is not to
be regarded as a serious pest of the apple in the sense that it will
require independent treatment.
After the insect has become established in orchards, and its im-
mediate control appears necessary, a thorough spraying of infested
trees with 12 or 15 per cent kerosene emulsion made in the usual way
would no doubt result in the destruction of the larvee and pupe in the
mines in the leaves, and possibly also of the eggs scattered over the
foliage. Such work, however, should be done on clear, bright days,
to lessen as much as possible danger of injury to the foliage from the
spray. Tests of a kerosene lime emulsion alone, and with Bordeaux
mixture and Paris green, have been reported by Prof. C. P. Close,
formerly of the Delaware College Agricultural Experiment Station,
in Bulletin 73 of that institution. In the experience of Professor
Close, applications in early August of 10 and 15 per cent kerosene
lime emulsions, with Bordeaux mixture and Paris green, were quite
effective in killing larve and pupe in the leaves. Applications of |
kerosene lime emulsions in September on the succeeding brood were |
not so successful in killing the insects, and the apple foliage was
injured, possibly on account of its weakened condition following the |
work of the miners.
as. AL. Bb. HW: Bul. 68, Part Iv. D. F. I. I., October 17, 1907.
PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
THE LESSER PEACH BORER.
(Synanthedon pictipes G. & R.)
By A. A. GIRAULT.
Engaged in Deciduous Fruit Insect Investigations.
INTRODUCTION.
Until recently the only lepidopterous porer of the peach known to
be common and injurious in the East was the peach borer (Sanni-
noidea exitiosa Say), an insect well known to entomologists and fruit
growers alike. About ten years ago—in 1896—however, another
somewhat similar borer, the subject of this paper, now called the
lesser peach borer, was mentioned by Webster as “ thé peach borer,”
and again, four years later, Smith recorded it as being sometimes
found on the peach in New Jersey, though apparently it was not con-
sidered a pest of any importance. It was with some surprise that,
in the investigation of the peach borer by this Bureau during the past
two years, this insect was discovered to be very abundant on peach in
Maryland and Georgia, and also to a less extent in western New York
and adjacent portions of Canada, occurring especially in the trunks
-of old or diseased trees. At first the larva was confused with that
of the peach borer, but dissimilarities in its habits soon led to its
recognition, which was confirmed upon rearing adults. Aside from
its being a practically unrecognized enemy of the peach, the insect is
of interest from the fact that it has heretofore evidently been more or
less confused with the true peach borer, to which the larva bears great
resemblance in general appearance. In subsequent pages there is
given as complete an account of the species as is possible at this date.
HISTORY.
Up to the year 1906 the species under consideration had not been
treated as an insect of special economic importance. Previous to
this time it had been known mostly as occurring on the plum and
3l
4
32 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
cherry, and it had not been sufficiently abundant to cause more than
occasional record of the fact in the literature of economic entomology.
For instance, it is not mentioned in the Catalogue of the Exhibit of
Economic Entomology at the Lewis and Clark Centennial Exposition,
Portland, Oreg., 1905, given in Bulletin No. 53 of this Bureau. It
has been listed several times, however, as occurring: on plums and
cherries, and in the following cases had been mentioned especially in
respect to its injury to these plants: Kellicott reported serious injury,
in some instances, to plums in New York State in 1881, but Smith,
nine years later (1890) ,* stated that it was rare in New Jersey. In
1892 Kellicott reported serious injury to cherries in Ohio. In 1899
Lugger thought the insect was increasing in Minnesota. Finally, in — |
1906, Quaintance reported it as very abundant in Georgia, causing
material injury to peach trees.
ORIGINAL DESCRIPTION; SCIENTIFIC NAME.
The insect was first described as new to science in 1868 by Grote
and Robinson, from adults captured in the “Atlantic district
(Penna.).” It was given the specific name pictipes and placed in
the genus Ageria of Fabricius. In 1881 it was redescribed as new
by Henry Edwards under the name of 4 geria inusitata, from speci-
mens obtained in the White Mountains, New Hampshire, and at
Andover, Mass. Twelve years later Beutenmiiller (1893) established
inusitata Hy. Edwards, as a synonym of pictipes. In the meantime
Smith (1890) had removed the species pictipes to the genus Sesia of
Fabricius, which removal was accepted later by Beutenmiiller (1896,
1897) and Dyar (1902). Soon afterwards Holland (1903), finding
that the name Sesia had been restricted to a genus of the Sphingide
by Fabricius, applied to the genus Hiibner’s proposed name, Synanthe-
don, which seems to be the proper course in this case (p. 385). The
insect’s scientific name, therefore, is Synanthedon pictipes (Grote and
Robinson ).
COMMON NAMES.
Owing to the fact that the lesser peach borer feeds in the larval
stage on a variety of trees it has become known by local or common ~
names, depending on its most common or most important food plant
in particular localities. It was first found on plum, and hence was
first called, by Bailey in 1879, the plum-tree borer, which has since
been the name oftenest applied to it. In 1896, as previously men-
tioned, Webster referred to it incidentally as “the peach borer; ”
and in 1906 it was designated by Starnes as “ the wild-cherry borer.”
In the same year, however, because of its increasing abundance on the
a@ Dates in parentheses refer to the bibliography at the end of this paper.
THE LESSER PEACH BORER. 33
peach and apparent preference for this tree over others hitherto
chosen, Quintance proposed for it the name of the lesser peach borer,
in distinction from. the better known peach borer Sanninoidea
exitiosa Say. This name seems preferable to any of the others, and
more logical, because the peach is the most important food plant
which it attacks at the present time.
FOOD PLANTS; CHARACTER AND EXTENT OF INJURY.
It has already been indicated that the lesser peach borer has more
than one food plant, a habit usual with the members of the family
to which it belongs. Bailey, in 1879, first found it on the cultivated
plum. Two years later, in 1881, Kellicott found it attacking old plum
trees at Buffalo, N. Y., and also wild cherries (Prunus serotinus and
P. pennsylvanicus). In 1891 the same author stated that, in addi-
tion to its favorite food plant, it also attacked wild black and red
cherries at Columbus, Ohio, and very probably would be found on
the cultivated cherry. Again the following year (1892) he briefly
states that it attacks both cultivated and wild cherry in the same
locality of Ohio. In 1893 Webster reared the insect from the
black-knot fungus, Plowrightia morbosa, on cherry and plum.
Beutenmiilier (1896), three years later, gave two additional food
plants, juneberry (Amelanchier canadensis) and the beach plum
- (Prunus maritima). During the same year Webster (1896) recorded
it on peach. Beutenmiiller (1897) then added chestnut, and in
1899 Lugger added wild plum, making the following known food
plants to date: Cultivated and wild plums and cherries, black-knot
fungus on plum and cherry, juneberry, beach plum, chestnut, and
peach.
Recent records of this Bureau show that this borer has a decided
preference for peach. For instance, in Georgia where large plum
and: peach orchards are grown side by side, an examination of each
kind of tree showed that it was common on the latter and scarce on
the former. We have been unable to find it numerous on wild plum
and cherry in that State, nor have additional food plants been found.
In Maryland we have found the larva in a knotty growth on peach
some 5 feet above the ground. Mr. W. F. Fiske, of this Bureau,
reared adults from girdled chestnut trees (Castanea dentauta), at
Tryon, N. C., May 28, 1904.
The insect is evidently increasing on peach, and at present in cer-
tain localities causes costly and, in the case of individual trees, fatal
injury. Bailey (1879) records a fatal attack on a plum tree in New
York; and as an example of such concentrated attacks on individ-
ual trees in orchards mention may be made of the case of a nearly
girdled 3-year-old Greensboro peach tree in Georgia, from the slender
34 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
trunk of which were taken 14 pupa, 1 larva in cocoon, and 28 larvee
-of various sizes.
The attack of this insect is somewhat similar to that of the peach
borer, but differs in many respects. Apparently it attacks none but
injured trees, where the bark has been injured in various ways, and
it is therefore usually found in old trees where this condition is more
likely to occur (see Pl. VI, fig. 3). Further, the larve occur upon
the trunk as a rule, make more irregular and longer burrows, and
generally follow the outlines of wounds or along the edges of the
cracked bark. They may be found, however, at or slightly below
the surface of the soil and above the crotch or fork of the tree in the
larger branches. The larvee feed on the soft tissues of the hving
bark, and an infested tree exudes a considerable amount of gum from
the area in which they are working. In some of the Georgia and
Maryland peach orchards groups of old, scarred trees have been
found with their trunks literally honeycombed by the channels of
these larvee, and this is hkely to be the condition in any neglected
orchard in which the trees have reached some size. An average of
two larve to the tree was found in 14-year-old trees in Georgia in
1906, but occasionally individual trees were discovered harboring as
many as 40 or 50 specimens of the insect in various stages.
DISTRIBUTION.
The lesser peach borer is rather widely distributed in the United
States, to which it is native. In his List of North American Lepi-
doptera, Dyar (1902) simply gives “ U. S.,” denoting general dis-
tribution. Beutenmiiller (1901), in his monograph of the Sesiide
of America North of Mexico, gives from Canada to Florida and
Texas, westward to the Pacific. It has been recorded from the
following States: New York and adjacent portions of Canada, Penn-
sylvania, New Hampshire, Massachusetts, Illinois, New Jersey, Ohio,
California, North Carolina, Minnesota, Maryland, District of Colum-
bia, Virginia, and Georgia. It has been recorded as common and
locally injurious in New York State and Ohio. The records of this
Bureau (Quaintance, 1906) report 1t common in Maryland, western
New York and circumjacent territory, and in Georgia, where it is
especially abundant. It is known to occur on peach in New Jersey,
Ohio, New York, Virginia, Georgia, District of Columbia, and
Maryland.
LITERATURE.
The literature of this insect is not extensive. Bailey (1879) gives
the only account of its life history yet published, and his description
Bul. 68, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE VI.
LESSER PEACH BORER (SYNANTHEDON PICTIPES).
Fig. 1, Male and female moths (male above); fig. 2, cocoons as exposed by removing bark from
trunk of peach tree; fig. 8, trunk of 10-vear-old peach tree badly infested with the larve.
Figs. 1 and 2, enlarged twice; fig. 8, much reduced. (Figs. 2 and 3, original; fig. 1, from
Quaintance. )
quent emergence of
THE LESSER PEACH BORER. BD
of the character of injury is especially good. From time to time it
has been treated systematically and figured, or listed, and for such
treatment reference should be made to the bibliography given at the
close of this article.
LIFE HISTORY AND HABITS.
The winter is passed in various stages of larval development under
the bark of the trunks of the trees. Upon the approach of warm
weather, and during warm spells in the winter in the South, the
larve feed, and as they reach full growth construct cocoons and
pupate (in March and April in Georgia and Maryland, respectively).
About a month afterwards the moths begin to emerge and mate, and
the females. at once commence to deposit their eggs along the tree
trunks. On account of the unequal development of the hibernating
larve, the period of
pupation and _ subse-
the adults lasts for
several months. The
eggs hatch after
about ten days, and
the young larve en-
ter the bark through
crevices and begin to
feed. In Georgia, in
the course of several
months, these larvee pre. 10—The lesser peach borer (Synanthedon pictipes): a, Adult;
reach full orowth and b, outline of eggs; c, larva; d, pupa; e, cocoon and pupal skin,
= (Original. )
pupate, and the re-
sulting moths establish another generation in the early fall,
‘) => .
which hibernates as larve. The two generations are considerably
mixed.
The seasonal history of this borer is therefore very unlike that of
the peach borer. It differs markedly in the fact of a partial second
generation, and the further fact of early spring pupation.
The egg—The egg (fig. 10, 6) is a small, compressed, elliptical!-
oval, reddish-brown object, similar in general to the eggs of the
peach borer and other members of the family .geriide. It har-
monizes in color with the bark of the trees upon which it is deposited,
and on this account is difficult to find. Seen from the side the ante-
rior end is truncate, but viewed from in front it is found to be con-
cave, the micropyle situated in the center of the concavity. The
upper side of the egg, as seen when in position on a tree, is com-
36 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
pressed and concave, the hollow being oval and following the out-
line of the margins; the bottom side or base is flat. The surface is
rough and sculptured into irregular polygons with from three to six
sides. The eggs are adhesive, hard, visible to the naked eye, but
minute, measuring 0.63 by 0.38 mm., and are deposited singly. They
differ in aspect from those of the peach borer, and also are usually
lighter in color and not as large and stout. They are rather more
difficult to find in nature.
At present the length of the period of incubation is not well known.
Mr. Quaintance records it as 74 days in the month of September,
latitude of Washington, D. C. Upon hatching, the little larva
cuts its way through the anterior end of the egg, leaving quite a
large exit hole in the egg shell, which retains its shape and place
until it weathers off.
The eggs were first observed in nature by Bailey (1879); he found
a cluster of them on the under surface of loosened plum bark, about
6 inches above the roots. Usually, however, they are deposited
singly along the trunk of the tree, being placed in crevices, openings.
or roughened places. Sometimes a few are placed on the ground or
high up in the tree on twigs or leaves, but the majority are de-
posited on the main trunk of the trees. The number deposited by
a single female is unknown. Moths kept in confinement refuse to
mate, and the female deposits few eggs or none at all. To determine
the number resort is therefore made to dissection. Mr. Quaintance
dissected two fertile females after death, and found 305 perfect eggs
in one and 296 in the other, in addition to numbers of small unde-~
veloped ones. Each moth had deposited a few eggs before dying,
which were included in the count.’ Dissection of the ovaries of a
sterile moth yielded but 58 perfect eggs, but there were present —
many undeveloped ones. Until more dissections are made the evi-
dence on this point remains inconclusive.
The larva.—When the larva hatches it is very small, and especially |
hard to detect with the naked eye because of its dull white color. It |
is an ordinary caterpillar, bearing the usual setsze and number of pro- |
legs, and in its earlier stages is almost indistinguishable from the
young larve of the peach borer. However, after molting once or |
twice it acquires a different aspect, which together with a more? |
pinkish and translucent color makes it somewhat more distinct.
Throughout all its life it remains about the same color—various |
shades of creamy white—and lives concealed under the bark. The
following is a description of a full-grown larva, or instar VI:
Length, 20.5 mm., average. Greatest width, 3.4 mm. Width of head, 1.94
mm., average. Normal for the family: Body soiled cream color, immaculate,
with the usual more or less generalized characters. Head yellowish brown,
|
THE LESSER PEACH BORER. o7
darker at base of clypeus and on labrum and mandibles, and blackish at the
lower outer angles of the paraclypeal pieces, edges of clypeus, and tips of the
mandibles; pale at vertical triangle, outer edges of paraclypeal pieces, gular
surfaces, epistoma, palpi, and antennze, the last two somewhat darkened;
mandibles broad and short, indistinctly five-toothed, the two inner teeth mere
serrations, the third tooth short, truncate, and broad, one-half shorter than the
second, which is shorter and broader than the first, which is also obtuse; cut-
ting edge of mandible oblique; two setze present, arising together from middle
of inner edge. Clypeus long, acutely triangular, its lateral margins sinuate, not
distinctly truncate at basal corners, which are impressed and bear two setz,
one caudad of the other; paraclypeal pieces long, narrowed centrally, including
the clypeus; on the inner side of each paraclypeal piece near the posterior end
is a slight depression from which arises a small seta, near the apex of the
clypeus. Ocelli 6, weak, pale, the first four in a quadrangle, each with a dis-
tinct lateral pigment spot; the fifth more cephalad, ventro-laterad of antenna,
also with pigmentation; the sixth smaller, caudo-laterad of the fifth, and with-
out pigmentation; the group protected by sete.
Cervical shield pale yellow, bearing twelve setz, in two groups of three each on
each side of meson, all separated, and the caudal one of the first group separated
by a suture; laterad of the shield, cephalad of spiracle, a group of three from a
ealloused tubercle, of which the cephalic two are much the longer; directly
laterad a group of two from a fleshy elongate tubercle, the caudal seta the
larger ; between these setigerous tubercles, caudad and opposite the spiracle, is a
narrow nonsetigerous tubercle, much narrower than the second setigerous one
(one next to the fore leg); spiracle oval, brownish; “ vii” and “ viii” small,
on the venter (7?) and base of fore leg. On segments II and III, i in the dorsal
region consisting of two sete, the laterad larger; ii the same, slightly advanced,
dorso-lateral aspect; iii single, minute, caudad between ii and iv, nearer the
latter; iv single, large, in a line laterad with iii, advanced slightly beyond i,
and in the stigmatal line; v small, its setz larger than iii, single, much advanced,
cephalo-laterad of iv; vi some distance caudo-laterad of v, about in a line trans-
versely with i, single, equal to iv, above base of leg; all in the second annulet.
A calloused spot behind iii, and a smaller one above vi, some distance caudad of
y. Segment IV, single, i cephalad, small, in first annulet; ii larger, caudo-
laterad of i; i and ii from dorsal aspect, forming a trapezoid; iii some distance
from i in a transverse line, equal to ii, apparently in the first annulet, just
above spiracle; iv and v combined just below the spiracle, the seta of v larger;
vi caudad, nearer to vii than to iv and v; vii consisting of two setz# in the
ventro-lateral line, and viii of one seta in the ventral region, minute; a minute
calloused spot behind iv and vy. Segment VY, the same, vii consisting of three
sete, one of which may be obsolete. Segments VI, VII, VIII, and IX, the
same; vii, three setze on cephalo-lateral aspect at the base of proleg: viii, minute
and single, inner side base of proleg; the intermediate seta of vii longest. On
segment X, ii caudad of i, vii consisting of two set, the inner the larger, vi
nearer to vii. Segment XI, i and ii closer, the latter also closer together trans-
versely, iii cephalo-mesad of the spiracle; iv small, against, and cephalad of
the spiracle; vii a single seta. Segment XII, i apparently absent; ii, iii, and
iv in a transverse line, iii and iv combined; v minute, between iv and vi,
slightly cephalo-laterad of iv; vi large, cephalad; vii and viii single. Anal
shield subobsolete, pale, bearing four large setz on each side, minutely maculate.
Segment XIII, four minute tubercles across the venter (vii and viii ?), in
front of each proleg, and just below the shield, a line of five on each side of the
segment, of unequal size.
38 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
Spiracle oval, inconspicuous, brown; that of segment XI larger, somewhat
obliqued, and farther dorsad. The crotchets of the legs are variable in number,
often unsymmetrical, and generally arranged as follows:
rroleg. Anterior row. Posterior row.
il 14-18 12-14
ye 14-17 12-15
ay 14 a
4, 12 all
Anal. 8 0
For the first four prolegs, the crotchets vary from 11 to 18 in number; for the
anal proleg they vary from 8 to 9. There are generally more present than in
Sanninoidea exritiosa (see fig. 10, ¢).
As compared technically with the full-grown larva of the peach borer, the
latter is 34 mm. long, 6 mm. in greatest width, with the width of the head
at least 83 mm. The head of NS. exitiosa is slightky darker in color, with a dis-
tinct, though variable, subtriangular pale area on each epicranial lobe, where
they join below the vertical triangle; the mandible is relatively more robust,
darker at the teeth, four of the latter distinct, the second tooth longest and more
slender, the outer next in length, the third one-third shorter than the second,
and obtusely rounded, the fourth a distinct tooth, but abruptly shorter, approach-
ing the fifth, which is a mere serration; the two mandibular sete are larger.
The lateral margins of the clypeus are straight, each one changing angle at its
basal third, making the clypeus shaped like (4, instead of triangular; the basal
corners of it are truncate. The parclypeal pieces are generally straight, but
curving basally to follow the margins of the clypeus; they are uniform in width.
The first two ocelli and the sixth are practically pigmentiess. The shields are
darker yellowish. The arrangement of the tubercles is the same, but they are
relatively larger, as are also the accessory warts and the setz. There is a less
number of crotchets in the prolegs, ranging from 8 to 16, and in the anal proleg
from 5 to 8.
Though these technical differences exist, they can not be recognized
in all points without considerable study, and an examination of a
series of larvee. The most conspicuous difference is the greater size
of the larva of Sanninoidea exitiosa and its different aspect.
During the course of its growth the larva molts several times, each
casting of the skin marking the end of a separate period of larval
development called an instar. There is no direct evidence by rearing
to show how many of these instars there are, but it has been shown
that the heads of lepidopterous larve are of certain limited sizes in
each instar, and therefore by measurements of a large series of the
heads of these larve, the conclusion is reached that there are six, as
shown in Table I. The larva molts five times. The length of the
separate instars has not been determined, but Mr. Quaintance records
a little over seven months as the length of the larval stage for an
individual reared on peach out of doors, from September to the fol-
lowing April, in the latitude of Washington, D. C.
ENR Se:
' THE LESSER PEACH BORER. 39
TABLE I.—Measurements of the head of the larva of Synanthedon pictipes in
each of the six instars.
FE. II. Iil. EVs Vi 88
mm. mim. mm. mm, mm. mm.
LGN e A a ee 0. 27 0. 55 0. 86 1.18 1.53 1.94
0 EE nea APS OB SASS peas areneae (a) (b) 0.72-0.95 | 1.02-1.25 | 1.36-1.70 | 1. 84-2. 64
BMOTOMCO’. ooo. 3 anise oe pe Lh Sg ee ee sed RE ee en ee Ae 0. 23 0. 23 0.34 0. 80
« Constant. ’Not obtained.
After hatching the young larva enters the tree by the way of a
crevice and soon begins to feed on the soft living tissues. It grows
rather rapidly and makes an irregular burrow between the living bark
and wood of the tree. This channel, in time, becomes filled with
— semiliquid gummy exudations and the reddish frass of the larva.
Where the larva enters there is left a small pile of fine reddish wood
dust. It is partial to wounds or diseased areas on the trunk, but, as
formerly stated, may occur anywhere on the tree, from the crown of
the root to the larger branches, and thus may be found feeding side by
side with the peach borer.
In confinement the larve will feed readily and grow on fresh
pieces of peach bark; Mr. Quaintance has fed one for several days
on peach leaves. When young, they are able to suspend themselves
with silk, and Bailey (1879) has observed them “ drinking ” moisture.
After the larva attains full growth and is ready to pupate, if some
distance from the edge of a wound or crack, it cuts a hole through,
or nearly through, the outer bark, and constructs a cocoon under this
in a suitable cavity, so that its anterior end is against the opening.
If it is near the edge of ruptured bark, which is more commonly the
case, the cocoon is made just within the boundary of the wounded
area, so that the pupa easily pushes out when ready to issue as an
adult. In old peach trees with cracked bark the cocoons are usually
found in this position.
The cocoon is constructed of pieces of bark chewed into fine bits,
frass, and silk secreted by the larva, and is light yellowish brown in
color and soft to the touch. An old cocoon, however, is dark in color,
and hard and brittle. The size of the cocoon varies, but it is always
several millimeters longer than the pupa which it incloses.
The pupa—tvThe larva, having formed a cocoon and inclosed itself
within, waits several days and then pupates. The pupa (fig. 10, @)
is brownish yellow in color, darker at the edges of the segments,
sutures, head and wing covers, spindle-shaped, and is’ broadest at
the first abdominal segment. It has all the characters normal to its
family. The sete are sparse and minute. The spines on the first
abdominal segment are very weak; in the female there is but a single
40 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
row of these spines after the fifth abdominal segment, and in the male
after the 6th abdominal segment. The secondary sexual characters
are therefore distinct (Beutenmiiller, 1901, p. 231). The cremaster
consists of eight stout spines surrounding the anal end. Structurally
the pupa is similar to that of the peach borer, but easily distinguished
from it by its much smaller size and lighter color, by the smaller and
lighter cocoons, and by the more finely granulated structure of the
latter. The pupa varies considerably in length, being from 10-17
mm., averaging about 14 mm.
Just after scr the pupa is nearly white, gradually turning
darker and becoming its normal color after some hours. As the in-
star approaches its close, it turns darker and darker, gradually assum-
ing the color of the inclosed moth, becoming steel blue-black a day or
so before emergence. Emergence, however, may be delayed several
days after the assumption of this color. In the cocoon the pupa is
naturally covered with more or less moisture.
The duration of the pupal instar varies according to season and
latitude. At Myrtle, Ga., and vicinity records of actual instars ob-
tained during 1906, from pupe first formed, in the late winter and
early spring, showed a maximum period of 32 days, and a mini-
mum period, toward the end of April, of 20 days. In the latitude
of Washington, D. C., records obtained in 1905 for first pupee, formed
in April, the adults emerging early in May, gave the actual pupal
instar from 20 to 30 days. By the oe of May in the same lati-
tude the period had decreased to from 153 to 17 days, where it re-
mained for the rest of the month. Mr. W. F. Fiske records the
actual pupal instar at Tryon, N. C., as being about 26 days during
May, 1904. These records do not include the several days spent in
the cocoon as a larva, which must be added.
Immediately preceding the final ecdysis the pupa becomes restless
and somewhat swollen, and, by aid of the rows of spines with which
it is armed, rather quickly works its way through the anterior end of
the cocoon up to about its fourth or fifth abdominal segment. The
moth emerges while the pupa is in this position, projecting for more
than half its length from the cocoon. (See fig. 10, e.)
The adult—Moths of the lesser peach borer (fig. 10, a, and Pl. VI,
fig. 1) resemble in general others of the family AXgeriide and more
particularly the males of the peach borer. They may be distinguished
most easily from the latter by the fact of their bearing but two yellow
bands on the abdomen, on the second and fourth segments, respec-
tively, the band on the fourth segment sometimes not entirely encir-
cling it; whereas the male of the peach borer has a yellow band on the
posterior margin of each of the abdominal segments, some of which
may be more or less obsolete. The males of the latter are also larger
than the moths of the former, but again agree in having a general
| ‘ THE LESSER PEACH BORER. 4]
~hymenopteriform aspect, but flying in the bright sunlight the two
"species are easily recognized after a little practice in observing them.
The sexes of the lesser peach borer are quite similar, but may be dis-
tinguished by one or two minor secondary characters, such as the
simple antenne of the female and the more robust abdomen and
‘straight anal tuft. Probably the most available secondary character,
however, is found in the frenulum, which in the female consists of
wo closely applied, long, and slender spines, while in the male it is
single and slightly shorter. This character is concealed by the front
wings.
The adults emerge from the pupe in the morning hours, generally
between 7.30 and 9.30, the males issuing slightly earlier than the
females. They are more likely to issue on clear days, being somewhat
retarded by cloudy or inclement weather. At the time of ecdysis the
pupa, which is projecting from the cocoon as described, commences
peristalsis-like movements of the abdominal segments, which after
several seconds cause the pupal integument to part rapidly along the
meson of the thorax and the sclerites of the head and wings. Almost
simultaneously with this parting of the pupal integument, the moth
begins to move forward and glides out, the forelegs holding to the
nearest object to prevent it from falling. The actual emergence re-
ires but a few seconds. At this time the moth is perfect but -for
folded wings, and can move with a peculiar jerky, gliding motion
vhen it falls to the ground or is disturbed, but otherwise it prefers to
remain motionless or to crawl to a convenient place. During the
folding of the wings, when the moth is weak and delicate, it is
wobably in the most critical stage of its existence. If it falls, it is
likely to injure the soft wings and become crippled, in which case it
rill almost certainly die a few hours later. The slightest injury at
his period appears to be fatal directly or indirectly. The wings
egin to swell at once and slowly expand, becoming normal after
bout 8 to 10 minutes. After expansion, however, they are still
eak and unfit for use for at least another half hour.
As soon as ready for flight, the female moves to a convenient place
nd, taking position, begins to attract the males by elevating the end
f the abdomen and extending the ovipositor horizontally from it.
{o perceptible odor is present. In badly infested orchards the males
ill begin to arrive after 3 or 4 minutes, or earlier, and soon a swarm
of a dozen or more will be humming around the female. The sexes
unite suddenly; the male grasps the female with the claspers, and
hen turning assumes the position normal to the Lepidoptera. Copu-
ation may last a variable time. Mr. J. H. Beattie, then connected
with this Bureau, observed a pair remain in copula for 65 minutes
on August 16, 1905, at noon, and an observation made in the late sum-
-Iner of 1906 gave 58 minutes. In case the weather is unfavorable
10090—Bull. 68—09-——4
a
——— OO ee oe
per oe
ee
42 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
or no males appear, the females will continue to await them for
several days, during the time from about 10 a. m. to 3 p. m.
Oviposition commences soon after copulation and continues through-
out the hfe of the female. On warm sunny days it may begin as’
early as 8 o'clock in the morning, in the South, and continue at inter-
vals through the day until as late as 4.30 p.m. On very windy or
stormy days the female is inactive, hiding in the grass in the orchard
for shelter, and on cloudy days she is less active than on clear ones.
During the period of oviposition she flies very rapidly, and is hardly
discernible until she alights on the trunk of a tree; she then moves
slowly over the bark and feels with the end of the yellowish ovi-
positor for a rough place or crevice, where she usually places an egg.
Ovipositing females are exceedingly difficult to follow with the eye,
and in this respect they differ markedly from the comparatively
sluggish and more conspicuous females of the peach borer. Further,
they are apparently more careful in placing eggs, always selecting
a place which will make it easier for the larva to get into the bark,
though enough observations have not been made on this to justify a
positive statement. ;
In flight both sexes resemble wasps and make a distinct buzzing
sound. The males are seldom seen. The moths have never been ob-
served to feed, except on moisture, and in confinement show no
marked attraction to sweetened water. Meager observations made
on adults kept in confinement indicate that they probably do not live
longer than a week.
SEASONAL HISTORY.
GENERATIONS.
The number of generations occurring with an insect of this kind
>
is especially difficult to determine because of the nature of its habits.
In Georgia some attempt has been made by this Bureau during th
past two years to obtain accurate knowledge on this point by keeping
during the entire breeding season. So far, however, the data obtained
do not warrant a definite or positive statement concerning the actual
hatched and nearly full-grown specimens are present, the former
indicating late fall, the latter, late summer, oviposition. As soon as ~
spring begins to open the old larve commence to pupate, emerging a |
month later as adults; the young larve feed and grow rapidly, pupat- ~
ing in their turn, and producing a continuous supply of moths. ‘The ©
moths from the hibernating larve produce another mixed generation |
THE LESSER PEACH BORER. 43
of larvee which reach full growth and begin to pupate and emerge as
moths in the late summer and early fall. In turn these early fall
adults oviposit, producing a mixed generation of larve throughout
the fall of the year; these pass the winter and mature the following
spring. Hence two cycles of this insect are clearly indicated during a
calendar year in the latitude of Georgia. A clearer conception of
the probable occurrence of these two generations may be obtained
by consulting Table IT.
TABLE I1.—Generations of the lesser peach borer at Myrtle, Ga., 1905-6.
Generation No. | Larve. | Pupe. Moths out. ior okerele
Pe NVUMberas elas Septs LO—Miay fos...) Mar. 1-May 20 (Apr.).| Apr. 1-June 20 (May) .| 74 months.
2. Summer ...:| Apr. 10-Aug. 1 (May | July 20-Oct.15(Sept.).) Aug. 15-Nov. 20(Sept.| 4; months.
and June). | and Oct.).
In Georgia, in 1906, the first pupa of what may be called the winter
generation was found on February 27, and by the middle of March
-they were common. A month later, in April, the adults of that gen-
eration were common, continuing so throughout May and part of
June. By the latter part of May the pupe became scarce, showing
that by this date the winter generation was practically over. From
that date on we conclude that the larve then present in the trees were
practically all of the next, or summer, generation. By the last week
in July pup were again found in numbers, and continued to increase
well into September, when adults of the summer generation were ob-
served ovipositing. The winter generation, therefore, became estab-
lished mainly in the latter part of August and during the whole of
September, and the larvee from eggs deposited then had ample time to
obtain at least two months’ steady growth before being disturbed by
cold weather. The foregoing statement is based on series of ‘speci-
mens collected weekly throughout the entire season of 1906, from
February to November, at Myrtle, Ga., by Mr. A. H. Rosenfeld and
the author, combined with records obtained by Mr. James H. Beattie
during the investigations in 1905 at Fort Valley, Ga.
Observations made in the vicinity of Odenton, Md., and Washing-
ton, D. C., show that the pup were present in the spring as early
as the first week in April and that adults issued from these during
the first half of May. The pupe continued present as late as May 8,
but thereafter we have no records. Mr. Fred Johnson, of this Bu-
reau, records seeing adults at North East, Pa., on May 29; and at
Niagara, Canada, June 23, 1905, Mr. Quaintance found larve nearly
or quite full grown, and pupe and adults were present. Bailey
(1879) found the moths as early as May 25, in 1879, at Buffalo, N. Y.,
and made a general statement to the effect that they issue during
June and July. Kellicott (1881) reports the same months for New
York and Smith (1900) for New Jersey, and similar statements
|
|
|
44 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
have been made by the various authors. For northern latitudes we
are unable at present to form any definite conception as to the number
of generations.
LENGTH OF THE LIFE CYCLE.
The length of the life cycle or developmental period of a genera-
tion of the lesser peach borer, based on field observations, has already
been given in connection with Table II. The life cycle of the summer
generation was approximately 44 months, and of the winter genera-
tion 7$ months. Fortunately Mr. Quaintance has succeeded in actu-
ally rearing a single specimen of this insect through its entire cycle,
in the grounds of the Insectary of this Bureau. On September 5,
1905, he placed 8 recently hatched larvee in small artificial wounds
made 3 feet from the ground on the trunk of a peach tree. Each
larva was placed in a separate wound and the whole then protected
by a wrapping of paper. By October 1, not quite a month later, 5
of the larve were found in their respective wounds and had grown
remarkably, being from a half to five-eighths of an inch in length
(13 to 16 mm.). On the 24th of the same month, or just over a
month and a half after hatching, the five larve were still alive and
were either about to molt or had just done so; three of them measured
13 mm., one 16 mm., and the fifth, 19 mm., averaging about 15 mm.
The following spring, on April 5, 1906, another examination was
made, and it was found that 4 of the larve had perished. The re-
maining one was inactive, but began to feed voraciously five days
later, and by about April 13 had formed its cocoon and pupated.
The moth, a male, emerged on May 14, 1906.
The lengths of the respective stages: for this individual were as fol-
lows: Egg, 74 days; combined larval instars, 220 days; pupal instar,
31 days; making a total of 258 days, or 8.6 months for the cycle
(from August 28, 1905, to May 14, 1906). This agrees remarkably
well with time approximated for the winter generation in the South,
where the periods of larval inactivity during the cold months are
naturally shorter, and hence growth is more rapid. The individual
reared was a descendant of parentS from Fort Valley, Ga., mailed to
Washington.
NATURAL ENEMIES.
The lesser peach borer has a number of natural enemies, nearly all
of which are parasites belonging to the order Hymenoptera.
Elachertus n. sp., of the family Eulophide, as determined by Mr.
E. S. G. Titus, is probably the most common, and is an internal para-
site which is fatal to the host just before pupation. After the host
larva has constructed its cocoon the parasitic grubs eat their way
through its body and pupate nakedly in the host cocoon, entirely
filling it. As many as 138 of these parasites have been reared from
= = ome ~ Seeeiin Ab
THE LESSER PEACH BORER. 45
a single larva of the lesser peach borer. It has been found at Oden-
ton and Jessup, Md. (March to May, 1905), and at Fort Valley
(April, May, July, 1905), and Myrtle, Ga. (March, 1906).
Bracon mellitor Say is also a rather common parasite of the lesser
peach borer, and its method of attack is similar, being fatal to full-
grown larve in their cocoons. After leaving the body of the host
the parasite larve spin small compact cocoons side by side, which
completely fill the host cocoon. They pass the winter in this condi-
tion and emerge the following spring. Thirty-four males and 31
females of this parasite were reared from two host larve during
April, 1905. The parasite also attacks the larva of the peach borer
and has a number of other hosts. It has been found to occur in the
same localities as the eulophid parasite, but in Georgia, in 1906, 1t was
rarely met with. It was rather common in Maryland in the spring
of 1905. A species of Microbracon was also reared from the larva in
Maryland and Georgia.
During 1905, at Fort Valley, Ga., Mr. J. H. Beattie, then of this
Bureau, reared Conura n. sp. (determined by Titus), from the lesser
peach borer. The parasite emerged May 30 from the pupa. Also in
May he reared Pimpla annulipes Brullé, from the same stage of the
host. This is probably the parasite referred to by Bailey (1879).
Mr. Beattie also reared a species of Campoplex in May, 1905, and
a species of Mesostenus in May and June, at Fort Valley, from this
borer, making a total of six hymenopterous parasites, all of which
were determined by Mr. Titus.
An undescribed variety of Dorymyrmex pyramicus Roger, as deter-
mined by Mr. Theodore Pergande, has been observed to attack the
larva when exposed during “ worming.” This ant is very numerous
in the peach orchards of Georgia, in the vicinity of Fort Valley, and
will prey upon any insect which it is able to overcome. Ordinarily
it is unable to get to this borer. Occasionally, however, it will kill
recently emerged moths, and any larve which may have been over-
looked during “ worming,” but which had been exposed. Mr. Titus
reports this ant as being abundant on peach trees at Monticello, Ga.,
in August, 1905. ,
It is indicated that birds sometimes extract pup from cocoons
under loose bark, and Bailey (1879) mentions a woodpecker as ex-
tracting larve from the trunk of a plum tree.
~The value of the parasites of the lesser peach borer is greater than
that of its predaceous enemies.
PREVENTIVES AND REMEDIES.
From the fact that this insect prefers to attack trees which have
been injured or diseased, or are old, having wounded or checked bark,
46 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.
it is obvious that anything which will tend to mitigate or prevent
these conditions will in turn largely prevent the borer’s presence.
Therefore proper orchard management, keeping the individual trees
in a good, clean, and vigorous condition of health, avoidance of
mechanical injury when cultivating, and prompt treatment of wounds
made about the body of the tree, are the surest ways to keep the
orchard free from this insect.
For its control in orchards already infested there is but one avail-
able remedy, namely, cutting the worms or larve out of their bur-
rows. This is best done in conjunction with the regular “ worming ”
for the peach borer, the operator taking care to examine all portions
of the trees from the roots up to the large limbs above the fork. In
doing this it will be necessary to cut away portions of the bark, and
wounds so made should be promptly cleaned and treated with some
protective antiseptic, as thick Bordeaux mixture or the hme-sulphur
wash. All rough, cracked, or diseased areas should be cleaned out
and similarly treated, whether they are infested or not, as they form
points of entrance for the borers and are in other ways a menace to
the life of the tree. The “ worming” for this insect should be ar-
ranged for the early spring, if convenient, as wounds made at that
time heal more readily, and, besides, the larvee are then pupating in
numbers and can be more easily gotten at.
So far as known, other remedial treatments in the shape of caustic
or preventive washes are practically worthless in the control of the
insect, and their application would be merely a waste of money.
BIBLIOGRAPHY.
The following bibliography contains titles of practically all of the
literature on the lesser peach borer. All of the articles have been
seen and verified, excepting that of Grote (1882).
1868. GrorE, AUGUSTUS RADCLIFFE, and COLEMAN T. ROBINSON. asses de. ogee pe en 59-60
MMMM OINATACLORS. pect oc 3. =< 2)oeins 2 sis. + a 5 ne Oe 54-55
Ree eee seh OS onl die ne we 55-56
Ate eee tA te Ss on oS te 2 52
ELI GUISES, EE Sa ee a nr eS 60
NT oh SE Orn 2 a ea a Be 56
RemmOnme MOP Vraciss os ies << = 2,5" SW - SS 57-59
pian (ocodlune moth. os... .. <2 .5+=