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BY Sa

CircuLaR No. 101. Issued May 4, 1908.

United States Department of Agriculture,
BUREAU OF ENTOMOLOGY.

L. O. HOWARD, Entomologist and gf Tai OF AGRICULTURE
RECEIVED

1

THE APPLE MAGGOT OR “ RAXLROADVMORM.” 1908 s¥

(Rhagoletis [Trypeta] pomanglte Washi a A RY
By A. L. QuarnraSge, FOREST SHRVICE
PAO RS

AIS
AAI

S
In Charge of Deciduous Fruit Inséct Investigations,

Five important insect pests injure the fruit of the apple in the
United States, namely, the codling moth (Carpocapsa pomonella L.),
the lesser apple worm (Lnarmonia prunivora Walsh), the plum cur-
culio (Conotrachelus nenuphar Hbst.), the apple curculio (Antho-
nomus quadrigibbus Say), and the species under consideration.

IG. 1—Apple maggot (Rhagoletis pomonella) : a, Adult: b, larva or maggot; ec, funnel
of cephalic spiracle; d, puparium; e, portion of apple* showing injury by maggots.
a, b, and d, Enlarged; c, still more enlarged; e, reduced. (Original.)

The apple maggot, as the name implies, is the larva of a fly or
dipterous insect, and belongs to the family Trypetidee, which group
contains numerous other fruit-infesting maggots,* some of them very
serious pests, and, from their structure, mode of life, and feeding
habits, very difficult of control. Apples injured or “ railroaded ”
by the apple maggot show discolored winding burrows, or tracks, and

® Anastrepha (Trypeta) ludens Loew., the so-called Mexican orange. worm, is

~ an enemy of oranges in portions of Mexico, infesting also the guava and mango,
and A. dcidusa Walk. infests the peach in the same country. Rhagoletis
ribicola Doane infests currants and gooseberries in the United States, as does

also Hpochra canadensis Loew. R. cingulata Loew has recently been found to

be a cherry pest in this country, working in a way similar to the European
cherry fly, Trypeta cerasi Ll. (signata Meig.). Ceratitis capitata Wied., the so-

36878—No. 101—08

2

cavities here and there in the flesh, and when infested with several
larvee the pulp will be usually quite honeycombed with their burrows
and more or less broken down into a yellowish mass, merely held
together by the skin. (See fig. 1, e.)

DISTRIBUTION AND DESTRUCTIVENESS.

The apple maggot is a native American species, its natural food
being haws (Cratzegus), and in at least one instance it has been bred
from crab-apples. Its feeding upon cultivated apples is thus an ac-
quired habit, and although the insect has been reported from widely
separated points in the central and eastern States, indicating its pos-
sible general distribution, for some reason it does not attack the apple
throughout its range, but only in certain localities and portions of the
eountry. This circumstance is a fortunate one for the apple grower,
and from a scientific standpoint is of much interest. Walsh thought
it might be explained on the supposition of the development in the
New England States, where its injuries to apples were first noticed,
of a race of apple-infesting individuals, the descendants of which,
with the acquired habit, have been gradually distributed to other
localities.

The apple maggot was described by Walsh in the American Jour-
nal of Horticulture for December, 1867, pages 338-348, and also in
the First Report of the Acting State Entomologist of Ulnois, from
flies from eastern apples and from Illinois haws. Adult specimens
from this latter fruit had been secured by him some five or six years
earlier, and in July, 1867, he reared flies from maggots infesting ap-
ples from Connecticut, Massachusetts, and New York, and conclu-
sively showed the identity of the insects infesting haws in Illinois
with those infesting apples in the northeastern part of the United
States. In the New England States mentioned, however, the species
had been noted as an enemy of apple for some years before the time
of Walsh’s description. By 1866 it was common in the Hudson River
country, at North Hempstead, Long Island, in the Oneida commu-
nity in New York State, at East Falmouth, Mass., and probably in
Vermont, and it occurred in Connecticut.

called Mediterranean fruit fly, or Bermuda peach maggot, is widely distributed,
infesting a considerable variety of soft fruits, as oranges, peaches, plums,
pineapples, and bananas, but fortunately has not yet been introduced into the
United States. In Europe T'ephritis onoperdinis Fab. injures celery, and 7.
tryoni Froggatt seriously infests, in portions of Australia, bananas, peaches,
oranges, etc., and another species of this genus (psidi Froggatt) in that country
infests guavas. Trypeta muse Froggatt seriously injures bananas in the New
Hebrides. Some of these species are very general feeders, and the greatest
care should be exercised, especially in the case of the Bermuda peach maggot,
that they be not introduced into the United States.
4¥irst Rept. Acting State Ent. Illinois, pp. 29-338 (1867).
ferbe alto hy|

5)

In 1881 the apple maggot was reported by Professor Comstock ¢
from Ithaca, N. Y., in apples, and was bred by him from Crategus
at Washington, D. C. Professor Cook,’ in 1884, received specimens
from Delavan, Wis., where it was reported as doing very great in-
jury, and the year following, the insect was the cause of considerable
loss in Ingham and adjoining counties in Michigan.

Lintner,’ in 1885, gives the additional localities of North Ashburn-
ham, Mass., Franklin and Schenectady, N. Y., and Brandon, Vt. Its
introduction into Maine, as stated by Professor Harvey,’ occurred
prior to 1882, by which time it had become well established, and by
1899 occurred quite generally over the State. Its occurrence at Mont-
clair, N. J., was recorded in 1889 by Mr. E. Willams, in Garden
and Forest, page 527, and this locality is also given for the apple
maggot by Dr. J. B. Smith in his list of insects of New Jersey, page
687 (1899).

In 1894 Doctor Howard ¢ records the occurrence of the apple mag-
got from Waynesville, N. C., and Doctor Fletcher‘ records its first ap-
_pearance in Canada, August 31, 1896,in apples from Adolphustown,
Ontario. <As stated by Professor Lochhead it had become quite in-
jurious by 1902, more than one-half of the crop having been destroyed
in some orchards in Prince Edward County. Professor Osborn,!
on the authority of Professor Hine, records its occurrence in north-
western Ohio in 1904, and states that injured fruit comes on the mar-
ket at Columbus, though perhaps from outside of the State. Doctor
Chittenden ‘ notes that the apple maggot was unusually injurious in
Ohio in 1903. By 1905 the insect had extended its range in Canada,
as shown by the records of Doctor Fletcher’ of its occurrence at
Como and St. Hilaire, Quebec. The apple maggot is recorded from
Minnesota by Br cor Ww ashburn,* and the records of the Bureau of
Entomology show the additional localities of Dyberry, Pa., and
Douglas, Mich.

Numerous records of this Bureau, as well as published accounts,
show that the insect is generally distributed throughout the greater
part of the New England States, and that it is a very destructive

2 Rept. Ent. U. S. Dept. Agric., 1881-82, p. 196.
6 Rept. Mich. Hort. Soc., 1884, p. 200.
¢ Second Report N. Y. State Ent., p. 121 (1885).
@ Ann. Rept. Maine State Coll. Agr. Exp. Sta., 1889, Pt. III, pp. 190-241.
€ Insect Life, VII, p. 279.
f Rept. Ent. and Bot. Exp. Farms Canada for 1896, p. 257 (1897).
933rd Ann. Rept. Ent. Soc. Ont., p. 67, 1902. (1903).
“Bul. 46, Div. Ent. U. S. Dept. Agric., p. 88 (1904).
t Yearbook, U. S. Dept. Agric. for 1903, p. 563.
J Rept. Ent. and Bot. Exp. Farms of Canada for 1904, p. 238 (1905).
‘Bul. 93, Minn. Agric. Exp. Sta., p. 118 (1905).
[Cir. 101]

~

enemy to apples. The flies do not spread rapidly, and hence individ-
ual orchards or certain varieties of apples may suffer severely, while
those adjoining may be little injured. Although the pest was bred
from haws, in 1867, in Illinois, there has been but one record of its
infesting apples in that State.*

FOOD PLANTS.

The natural food of the apple maggot is wild haw (Crategus),
and probably several species are infested. It was bred from haws
by Walsh in Illinois, by Cook in Illinois and Wisconsin, and by
Comstock at Washington, D. C. Despite its supposed general occur-
rence in the fruit of this plant, no further records of breeding from
haws have been found, and Professor Harvey states that it was not
found in haws in Maine. During the past three years the Bureau of
Entomology has collected or received fruit of Crategus spp. from
various parts of the country, but has not observed it to be infested
with the apple maggot in any instance, and it appears quite doubtful
if the distribution of the species is as general as is that of its native
food plants.

The early statements of the probable feeding of this species on crab-
apple appear not to have been based on actual observations, and
aside from Riley’s record of its occurrence on crabs,’ no definite data
have been presented to show that it infests this fruit. Professor
Harvey thought it improbable that this fruit would be used, for the
reason that it is quite green and hard during the period of flight and
oviposition of the flies. The insect was found infesting plums and
late cherries in northern Michigan, by Professor Cook,’ in 1889,
though no additional records of its occurrence in these fruits have
been seen.

Of apples, sweet and subacid summer varieties are worst attacked,
but fall and winter sorts are also infested, including distinctly acid
varieties. Professor Harvey has prepared a list of apples showing
their relative degree of infestation as observed by him in Maine
during his careful study of the apple maggot.’

“Cordley, Orchard and Garden, 1889, p. 192.
6Am. Agric., 1872, p. 263.
¢ Second Ann. Rept. Mich. Agric. Exp. Sta., p. 153.
d Loc. cit.

[Cir. 101]

Varieties of apples known to

5)

be affected by Rhagoletis (Trypeta) pomonella.®

Flavor.
4 Time of
Variety. S Remarks.
Sweet ced Acid maturity -
Alloa TG Greta sera we eh SNe | aokilbag aaah, =|. Autumn____- | Sparingly infested.
IBYbI Oe (Gaianis (EXON a RADE) ee Win tersee es Do.
IBAlleVAS Wee Gis ee ees ae I! oft Seah ibs ESD Nata BEE Osea, j Do.
I a iyi ae eR ea ee ee eee enine [enc ee Ure) SO a eerea as GOxenae Do.
TBYey aN Oy an |S, Se as Mame aly ora ee ee a Bd eg SRN el ec ie Sy AUCUIMnE as Boe infested.
TEX OLD Kee anes er Te Ce ne ee a TE geet RE 3 en eee ll Summer___-_
Canada Baldwink 3 eee a eset leg MeO i lle ae Winter______ HRRE infested.
Waits hea Gee aan ea Te SP te ers Sy | eset Autumn____. Do
@henan OLS ieee SA ee ee SE SSE | (se Sy es | 1p Se Osea Badly infested.
Colviert Bae Meee) See eae ee ee) te cE (scien (a doOm= ie Sparingly infested.
Dan Ver sean ss Meese le TAL Ree ie IN Yi SES | Le ceca Winter______ Do.
DD AViCO mate press were ek Cae Leer piss ere be! Cre rte Soa |eete te dosaey Do.
DEED YA pins oe an Ce Rs oT jee cere pre |e e Saag dommware’ Do.
DH alka Ngee a NP Beas gens eg Bo, a | eS Aiea fils ake ah Autumn__-_ Do.
IH ATV eE a nVies t= sees sae ee eee SENS EEO a mpiinke aszckcaet Wa S| Saad, Laka aa Badly infested.
Esopus (Esopus Spitzenburg)___-_____ ________ te | teas wey Winter._222 Do.
Nae Senne Ghee ee wee aw Ae eA al ee afey rani Maen: Autumn=s22. Do.
TREN LSNy o op bay save i sa Fa ie eee a ener ree ea) age oyt eee Re doses Sparingly infested.
SLAITIC US Geer ee eee Oe OE Nn bee Talo ihe OCCT SS | fsa Winters Do
EE: QUAL TTY Savi trees eee Se Eire) (pint ze eae real (Se ne ey WE) Autumn_-___ Badly infested.
BUCrAT GENEL OV dle seein ee con em uly ety ef SERS Rell ebre a SRE OKO
Gold enke a lies ee ee a Sted alla eee el Winter 2s See ely infested.
GOlGEMPUS SG eer eee eek re ee ten Te ee, lel sa a ees doa Do
Gravenstelnieeemesce!: ates wie ec ee NT ees cy py | eater ay cme cee © GO eaae Badly infested.
ToT ES Sereda ee ee ee RL eee Al Keka i eel [el Gkoy Sparingly infested.
FEN ontop Sweeter as sae an Se als ee stay | (cee meseetines [pte te Autumn___-_. Badly infested.
Jali D) OG RO RON ee ee ee stom, a eee Win ters22= 8 Sparingly infested.
IERUT) DU barre sere ee Se Ree ee Ect us Eee di Autumn_-__-_. Badly infested.
ERISHYR GAC he ese ne ee ere Sea en eta Ir Ad teagan | eget Sell a qdoz2=es Sparingly infested.
OWL ie Gee eis rege Se ee a a ee oe = aber Loe Tee Winters wes Badly infested.
HERCLTY et Wi Gees nes ae Neuere ALS + Bi Pap tal aN | a ts gee Summer___-_ Do.
Pr cVAS WiCeto mee ek ia en a cal he eh Te on ee A ee Wilt eran Snaninely infested.
MiaTdenvB Tis ites. seas ae nae ee Ie te Wi ato | eee eel nS Autumn__-_:. Do
IMGXc1 CO Ee ae A a Ta OU ek ain) ES || ee Ie Rae, Gols Do
Wi (COYLE) OY 2Y ea MS hee Reng oa ner Est oS Dae ee ee pial ee partie op) Winter______| Badly infested.
Milne ee eee ee eel Ee ire Sit ene deo | eee Se Summer____| Do.
ING WAV GLI Sweetener h(a et | eae sec | Re fas Oza Do.
INOEE Meri Syn yes eet ee ek oeeetye | a Ae Se ee ete Wanters = Do.
(Ojkaleral ope (DYNO aa) Ee Oe =f Autumn____| Sparingly infested.
ZA AGI SC VS Wee Gene eee tee eee Se | | cea ea ee mee Winter. 2 Badly infested.
MG AGENT LTTE (67) oe ten tae ee ie cave Seek ile Ce as yh eae aah dos Do.
IRE VGA CaN (G2) eee Ee BR RO a M2 e e any eI eee ewan oe (8 Ae doe =a Sparingly infested.
TEXO TELE) Pas tibia oon Nee as J Seal Dt Rae al IE aes ahs ait peepee Autumn____| Badly infested.
IPOUNGES Wee Glasses lk Be SE ea eae geet ea Preece re Winter_____- Sparingly infested.
J PAID ONES eYSA Se ais aaar Sb bE IN e al d) F ea a SD (ese eae a Rae Summer___- Do
RUM p kay Siwee tases eee eek ee uate ne = Nae eee ear eee es pee Autumn____| Badly infested.
EV ATS Cle) eens eee Sa ee Fe NG 2S oi Kan et | SS Winters. Sparingly infested.
REG BAS GE a'c ae re ee ae eee eee eer | ews se a is ee Summer____| Badly infested. -
RMOdenistam dl Giree iti oe eee ea el ecg is | ees + Winters. Sparingly infested.
EG SGOT etd Po ae ee ena Pe a ees GA as eee |! oe alls Vee ape dou Do.
TRSV0) (nis We RS 0G EE | ts ee Hin) Saks aie | ak doa: Do.
UU SC LM Dats es SS aa Be A a EP Ue fea he SE S| pee ed = Sg ede De ae Badly infested.
SSO eee Se a cee eens SER nde he en |e A ti, | Pa ERS Autumn____. oO.
SOMO TS Cee a Re A ge ek sis SEN ag] Pace eee epee do eee! Sparingly infested.
S OPSTOTAWill eo weet ieee a te ee eee fe) | amore = nt) (Jee creer a Summer____; Badly infested.
Mefols kis sects abe s Meese ae A cS [teach eet 2 |e VE ER (0 (eae eo Do.
PROM ain ened fe Re eee ee eee ST i aoe cee ee ee Wanter- 22s Dosa
A Mop aaly oy baKe! Tp alps gs se ae fan aD en ee a Pe apy | ocak (oP ss IDS cried) dowel: Sparingly infested.
Teri tiye OUT CO mace seers: Cpe aie ay Nena FS. aT [ett ee Autumn__-_-_.
NAPA WERE OVS) ee Spt ye NS NN ark eR ee We oo Na 5 gl eae eee Winters
ATA SEET IE) ay = ee eS a al I a eae A BE cores aut ae ELL Oe ae Badly infested.
Westfield (Seek-no-further)____________|_---____ Sue | eek 2h aera ae a dos
AWTS Et Bie tee De ss ees Pee cau eres eae Summer____— Do.
Wain thio PKG ECM oes eee eee i ee See een oS Autumn_._-. Do.
ello weBell i Ow Cree eee see een | eg dierc ace Winters | Do.

@4Names of varieties of apples h
menelature of the Apple,’ by W.
Agric. (1905).

ave been corrected to agree with those given in ‘‘ No-
H. Ragan. Bul. 56, Bur. Plant Industry, U. S. Dept.

The susceptibility to injury of the respective varieties mentioned,
as observed in Maine, would not necessarily be true for other regions,
but the list will serve to show that all classes of fruit are subject to

[Cir. 101]

6

attack. Asa general statement, it may be said that the insect will be
most destructive to summer and fall varieties, or to those varieties
which are ripe or are approaching maturity during the period of
principal activity of the flies.

HOW THE INSECT SPREADS.

It is not known whether the apple maggot has spread from the
New England States, where its injuries were first noticed, to the sev-
eral localities where its presence has been observed—as in Ohio, Wis-
consin, Michigan, North Carolina, ete.—or whether the insect, al-
ready present on haws, simply turned its attention to apples. The
former view, however, appears the more probable, and its spread
would have been readily brought about by the introduction of in-
fested apples. In regions where the insect occurs in apples, a con-
siderable amount of infested fruit will be barreled, the larve later
deserting the fruit and forming puparia on the bottom of the barrel.
In the ordinary course of commerce the insect would thus be intro-
duced into new localities, often quite remote. In view of the extent
of apple production in the territory which has long been infested
with this species (1. e., the New England States), and the consequent
almost certain dissemination of the apple maggot to various parts of
the country, it 1s cause for much surprise that the insect is not much
more generally and widely established as an apple pest. It is very
probable that the insect has been introduced into most of the apple-
erowing regions in the United States and also into those of Europe
and the Colonies, but for some reason has not established itself.
Thus the insect has been frequently found in apples on the markets in
Washington, D. C., though there is no evidence to indicate that it
has become established in orchards in that vicinity.

When once established in an orchard, its spread fortunately is
usually very slow. It may confine its attack to a single tree, for two
or three years, before spreading to adjacent trees of the same or
other varieties equally subject to attack; and varieties seriously in-
fested in one orchard may be exempt in another. The slowness of
its spread from tree to tree and from one orchard to another has been
commented upon by numerous workers.

The flies in their habits are exceedingly local, apparently confining
their attention to the trees upon which the previous generation devel-
oped—in marked distinction to the spreading habits of many other
insects. This habit is a very fortunate one for the fruit grower, and
is of much practical importance in control, permitting great reduc-
tion and possible extermination of the pests when infestation is lim-
ited to but a few trees, and especially in localities but recently
invaded.

[Cir. 101]

i
DESCRIPTION.

Egg.—The eggs of the apple maggot are quite small, varying from
0.8 to 0.9 mm. in length by 0.2 to 0.25 mm. in width, fusiform, and
light yellow in color as taken from the fruit. A short, broad pedicel,
about one-twentieth the length of the egg, is found at the broader
end, which end is darker and pitted with irregular hexagonal cells
with raised lacerated borders for about one-fourth the length of the
egg. (See fig. 2, a.)

Larva—tThe larva (fig. 1, 6) is footless, and when full grown is
from 7 to 8 mm. long, with a width of from 1.75 to 2 mm., yellowish-

:% 6 0 0,
Ruin
ailete

Zl tn log 40,

BUPBDE

Cc

Fig. 2.—Rhagoletis pomonella: a, Egg; b, head of larva, showing chitinous hooks and
framework within the head, and funnel-shaped spiracle; c, caudal spiracle; d, oviposi-
tor, with which eggs are placed beneath skin of apple. All greatly enlarged. (0, ¢,
After Comstock; a, d, after Harvey.)

white in color, at times tinged with greenish. The body is composed

of 14 segments, widest across the ninth, tenth, and eleventh, and

sloping gradually backward, and more rapidly toward the head end.

The caudal end is truncate, and on the lower portion of the anterior

end (first segment) is a pair of black, curved, parallel hooks, attached

to a chitinous framework within the head, the hooks being used to

rasp the pulp in the liberation of juice for food. <A pair of spiracles

occurs on the dorsal surface on each side at the juncture of the first
[Cir. 101]

8

and second segments (fig. 2, 6) and a pair on the sloping surface of
the caudal segment. The spiracles on the cephalic end have funnel-
shaped mouths, the funnel being bordered with a double row of about
20 projections. ‘The caudal spiracles each show 8 transverse slit-like
openings and 4 groups of bristles. (See fig. 2, c.)

Pupa—The pupa is a small, barrel-shaped structure, pale yellow-
ish-brown in color, measuring about 4.2 to 5.2 mm. in length, with a
width of from 2 to 2.6mm. The larva in pupating does not shed its
skin, but. simply contracts, assuming an oval form, causing the
cephalic spiracles to project in front as tubercles. Although the cau-
dal end also shrinks, the spiracles are still visible, as are also the body
segments of the larva. The true pupa is formed within the larval
skin. (See fig. 1, d.)

Adult.—The parent of the apple maggot is a two-winged fly (fig.
1, a), somewhat smaller than the house fly, of a general black color,
with yellowish head and legs, greenish eyes, and dark feet. In the
male there are 3, and in the female 4 white bands across the abdomen.
Across the wings of both sexes are 4 black bands as shown in the fig-
ure. The females are from 5 to 6 mm. in length, with a spread of
wings of about 12.15 mm. The males are somewhat smaller.

LIFE HISTORY AND HABITS.?

There is but one generation of the apple maggot each year, though
the occurrence of maggots in the fruit during the summer and
autumn, due to the great irregularity in time of appearance of the
flies, is calculated to mislead those not familiar with the insect’s life
history. The time and appearance of the adults is thought to be
influenced by the date of the ripening of the fruit which they in-
fested the previous season, though this supposition has not been
established. During an ordinary season in Maine, the flies will
begin to appear and will be ovipositing about July 1, and earlier in
the States to the south. By the middle of July, in Rhode Island,
during an average season, as stated by Profs. F. W. Card and A. E.
Stene, early varieties subject to attack will show many of the egg
punctures of the females.

Flies have lived in confinement for three weeks, and out of doors
the period is doubtless somewhat longer. The female makes punc-
tures through the skin of the apple by means of her sharp ovipositor
(fig. 2, d), inserting the eggs singly into the flesh in a vertical posi-
tion. Oviposition may occur on any part of the fruit, though mostly
on the side and especially on the paler portions, where the apple has

“The apple maggot was carefully investigated in Maine by the late Professor
Harvey, and his Report (1. c.) has been largely the basis of the present article.
[Cir. 101]

a

been protected from the sun by the foliage. An individual female
is capable of producing from 300 to 400 eggs, egg laying continuing
throughout her life. About one-half minute is Becuped in the act
of depositing a single egg, and the characteristic brownish speck left
by the ovipositor can, upon close examination, be detected by the un-
aided eye, and resembles the brownish rusty spots occurring normally
on some varieties. These egg punctures may be best observed, how-
ever, with a hand lens, and are then seen to be oblong or circular
holes, with the surrounding border brownish and somewhat shrunken.
In four or five days, under favorable conditions, the egg hatches and
the minute footless maggot begins to feed on the pulp of the fruit.
Although the larva is without true opposable jaws, it is provided
with two hooks on the head above the mouth by which the pulp is
rasped loose, the larva drawing into the mouth the juices thus lib-
erated. The pulp which is not eaten soon turns brown and renders
the burrows through the flesh more readily visible. The larva, in
its feeding, channels here and there through the flesh, sometimes
burrowing for a distance just under the skin, the brownish trail in
hght- Jerned. varieties appearing as a linear bruise.

"The rate of development of the larve conforms to that of the fruit,
and the larve do not mature until the fruit is ripe. Early appearing
flies attack the summer varieties, and those appearing later infest
fall and winter sorts. Their development is checked by cold, and
they. are apparently able to exist for a considerable time in a prac-
tically stationary condition until the maturity of the fruit permits of
their further growth to maturity.

Apples at gathering time may show no exterior indications of in-
festation, yet when cut open will be found thoroughly burrowed and
honeycombed by the larvee; or the apparently sound mature fruit may
be so infested with the small, inconspicuous larve and eggs that it
may be soon destroyed after storing. The work of a single maggot
will injure the value of the fruit, though a dozen or more may often
be present. Under favorable conditions of temperature and in ripen-
ing fruit, the maggots will become full grown in four or five weeks.
The larve mature as the fruit is ripe, and leave this after it has fallen
to the ground, as no exit holes have been noticed in fruit on the trees.
In deserting the fruit a hole is made through the skin and the larva
burrows an inch or less below the surface of the soil, or on sod land
probably pupates around the roots of the grass; or sometimes the
pupal stage is entered on the surface of the ground under the de-
cayed fruit. In fruit in barrels, in storehouses, etc., the larve
pupate on the bottom of the receptacle, and the puparia are often
very numerous in such places. The insect remains in the pupal stage

[Cir. 101]

10

until the following summer, the adult fly appearing early or late,
depending apparently on whether the larve infested summer, fall, or
winter fruit.

INSECTS WHICH MAY BE MISTAKEN FOR THE APPLE MAGGOT.

There will often be found in apples partly or wholly decayed, as
from the work of the apple maggot or other causes, larve which
might very readily be mistaken for those of the species under consid-
eration. Principally the larve of two kinds of flies will thus be
found, namely, the vine-loving pomace fly (Drosophila ampelophila
Loew )—a small clear-winged, red-eyed fly—and the pretty pomace
fly (Drosophila amena Loew), similar to the former, but with black
spots on the wings. These insects are of interest as likely to be mis-
taken for the apple maggot and hence the cause of needless alarm.
They are of little economic importance, though undoubtedly hasten-
ing the decay of fruits.

PREVENTIVE MEASURES.

The apple maggot has proved to be an unusually troublesome in-
sect to combat successfully. The eggs are deposited beneath the skin
of the fruit, within which also the larva feeds until full grown. The
pupal stage is passed just under the soil, or around the roots of grass
in sod land, and the flies do not feed in a way to permit of their
destruction. Spraying with arsenicals, so effective against the codling
moth or apple worm, is for this pest quite useless.

The insect, however, may be attacked in two important ways. As
stated, the larvee do not leave the fruit until the latter has ripened
and fallen to the ground. The prompt gathering and destruction of
the windfalls, before they are deserted by the maggots, would serve
to keep the insects greatly reduced, amounting to practical extermina-
tion if thoroughly carried out. This practice has long been recom-
mended by entomologists, and comprises the most effective measure
of controlling the pest at present known. Greatest benefit will come
from the practice when carried out uniformly by the orchardists of a
community. Allowing the wormy fruit to decay on the ground is
most favorable to multiplication of the apple maggot. Orchardists
having this pest to contend with should arrange to destroy the in-
fested fruit promptly after it falls, and this may be accomphshed in
whatever way is most practicable under individual conditions.

Picking up the fruit by hand will often prove feasible and can be
done by children, but great care is necessary that the work be done
thoroughly. The gatherings should be made daily if possible, or at
least every two or three days. The fruit may be fed to stock, taking

[Cir. 101]

alt

care that any excess not at the moment needed be stored in tight
boxes or receptacles so that: any larve deserting the fruit will be
forced to pupate on the bottom of the container, where later they may
be destroyed. When the drop fruit is not needed for the stock, it
may be simply thrown into a hole or holes here and there in the
orchard, to be finally covered with 2 or 3 feet of earth in the late fall
after frosts have occurred, to prevent the escape of flies the following
season. The work of gathering need not be begun until the first ripe
windfalls of the early varieties are found, but should be kept up from
this time until all the fruit has been harvested.

Orchards may often be pastured with sheep, hogs, or cattle, in a
way to insure the destruction of the windfalls, and this practice is
recommended as the cheapest and most satisfactory method of deal-
ing with the apple-maggot problem. Orchards may be permanently
pastured or the stock turned in daily in sufficient numbers and at
times to accomplish the desired consumption of the fallen fruit. This
practice will be especially useful in commercial orchards, and, where
infestation from adjacent orchards is not great, will insure practically
clean fruit.

Plowing and cultivation of orchards would appear to be a useful
practice in the control of this pest, and these methods have been
more or less recommended for some years. Careful experiments in
Rhode Island on the value of such work have recently been reported
by Professors Card and Stene. Puparia of apple maggots were
placed at different depths in the soil, ranging from 1 to 6 inches, to
approximate conditions resulting from plowing to bury the pupe, but
this was found to have little effect in preventing the escape of flies,
and the conclusion was reached that spring plowing of orchards to
turn under the pupe was valueless, under the soil conditions which
there obtained.

It is thought, however, that frequent tillage of the orchard in early
summer may be unfavorable to the development of the pupe to
flies, and experiments made in 1904 by Messrs. Card and M. A.
Blake ® with pupz placed in boxes in which the soil was frequently
stirred, resulted apparently in their complete destruction. More ex-
tended and conclusive experiments along these lines are urgently
needed. Aside from its possible value in destroying the apple maggot,
frequent tillage of orchards in late spring and early summer is de-
sirable, especially for young trees, as favoring a better tree and fruit
development.

2 Seventeenth Ann. Rept. R. I. Agr. Exp. Sta., Part II, p. 191 (1904).
6 Highteenth Ann. Rept. R. I. Agr. Exp. Sta., Part II, p. 197 (1905).
LGirs OI

12

Much infested fruit goes to market, or is stored at home for future
consumption. The refuse from such fruit should always be de-
stroyed, and the barrels and boxes in which the maggots have pupated
upon leaving the fruit should be treated in such a way as to insure
the destruction of the pups. The floor of storerooms should also be
carefully swept, and the sweepings collected and burned.

Approved:
JAMES WILSON,
Secretary of Agriculture.
Wasnuinerton, D. C., March 27, 1908.
[Cir. 101]

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