The asparagus miner (Agromyza simplex Loew.)


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The asparagus miner (Agromyza simplex Loew.)
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Chittenden, F. H ( Frank Hurlbut ), 1858-1929
United States -- Bureau of Entomology
U.S. Government Printing Office ( Washington )
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* Y'


Issued March 25, 1911.

L. 0. HOWARD, Entomologist and Chief of Bureau.


In Charge of Truck Crop and Stored Product Insect Investigations.



qb --


L. 0. HOWARD, Entomologist and Chief of Bureau.
C. L. MARLATT, Entomologist and Acting Chief in Absence of Chief.
R. S. CLIFrroN, Executire Assistant.
W. F. TASTET, Chief Clerk.

F. II. CHITTENDEN, in charge of truck crop and stored product insect investigations.
A. D. HOPKINS, in charge qfforest insect investigations.
W. D. HUNTER, in charge of southern fitld crop insect investigations.
F. M. WEBSTER, in charge of cereal and forage insect investigations.
A. IL. QUAINTANCE, in charge of deciduousfruit insect investigations.
E. F. PHILLIPS, ln charge of bec culture.
D. M. ROGERS, in charge of presenting spread of moths, field work.
ROLLA P. CURRIE, in charge of editorial vork.
MABEL COLCORD, librarian.

F. H. CHITTENDEN, in charge

M. M. HIGH, FRED. A. J.OHNSTON, AWVi. B. PARKER, H. 0. MARSH, agents and
I. J. CONDIT, collaborator in Californii.
P. T. COLE, collaborator in tidewater Virginia.

CIRCULAR No. 135. Issued March 25, 1911.
United States Department of Agriculture,
L. 0. HOWARD, Entomologist and Chief of Bureau.

(Agromyza simplex Loew.)
By F. H. CHITTrrENDEN, Sc. D.,
In Charge of Truck Crop and Stored Product Insect Investigations.

The stalks of asparagus are frequently attacked by insects, and in
recent years have been reported considerably injured by the larva or
maggot of a minute black fly to which the name asparagus miner has
been given. The larva mines beneath the epidermis of the stalk, and
when it has transformed to the puparium or "flaxseed" stage the thin
outer skin becomes more or less ruptured and the presence of the
insect is easily detected. It operates more abundantly near the base

FIG. 1.-The asparagus miner (Agromyza simplex): Fly, dorsal view at left, lateral view at right. Highly
magnified. (Author's illustration.)
of the stalks and penetrates below the surface of the ground to a
depth of 7 or 8 inches. During the year 1906 this species attracted
considerable attention by its abundance in some of the principal
asparagus-growing sections of New England and it bids fair to become
a pest of considerable importance. It was first noticed on asparagus
in 1896, prior to which time nothing was known of its habits. It is a
native species and evidently restricted to asparagus as a food plant.
Until the year 1906 it had not been recognized as doing injury to
cutting beds, although attack had been observed in various sections.
a Revised reprint from Bul. 66, n. s., Bur. Ent., U. S. Dept. Agr.
79779e-CIr. 135-11 1


The mines of the larvae about and below the bases of the stalks are
frequently so abundant that they have the effect of girdling, so that
the injured stalks can readily be pulled from the ground.
The parent insect is a two-winged fly (fig. 1), metallic black, with
large prominent head and eyes, and clear wings, the wing expanse
being about one-sixth of an inch (4 mm.).
The larva (fig. 2, a) is about one-fifth of an inch long and milk-
white in color. Like other maggots, it is footless, large at the
-- posterior extremity, and tapering
6 -toward the head.
The puparium (fig. 2, d, e) is not
b NV t i unlike the "flaxseed" of the perni-
I^ I cious Hessian fly, with which it has
been aptly compared. At a little
q distance, also, it suggests a Lecanium
scale. This stage is remarkable be-
d, i cause of its peculiar flattened and
f curved position, as seen from the
FIG. 2.-The asparagus miner (Agromyzasii- side. It is red in color, and meas-
pier): a, Larva, lateral view; b, thoracic spir-
acles; c, anal spiracles; d, puparium from side; ures about 3.5 mm. in length and
e, same from above; /, section of asparagus about 1 mm. in width.
stalk, showing injury and location of puparia
on detached section, a-e, Much enlarged: /, The egg( has not been observed.
slightly reduced. (Author's illustration.) This species belongs to the dipter-
ous family Agromyzide, and was described by Loew in 1861,a the
locality being given as "Middle States."
In its injurious occurrences this species appears to be limited to the
eastern United States, from New England to Tennessee. From avail-
able data it is quite obvious, however, that it may be destructive over
a considerable terrTitory, including a large portion of Massachusetts
and Connecticut, Long Island, the District of Columbia, Pennsyl-
vania, and Tennessee. As it is recorded from New Jersey, it is prob-
ably injurious there, although no reports of injury in that State have
reached this office. In time it will doubtless attract attention in
intermediate points and in States farther north and west. It has also
appeared in asparagus beds in California.
In May, 1897, and afterwards this fly was observed in abundance
by the writer on terminal shoots of asparagus, particularly at Cabin
John, MId. Two weeks later no more flies were seen, but June 26
a Diptera Americau septentrionalis indigena, Centuria octava 84, p. 160.


they reappeared and were then usually seen in copula. It was sur-
mised at the time that this second appearance indicated the first new
generation of the year and its abundance on asparagus seemed to show
that it lived in some manner at the expense of that plant. Examina-
tion of asparagus plants at that time, however, failed to show attack.a
In 1900 complaints of injuries were made in the District of Colum-
bia, and at Knoxville, Tenn., and in the meantime the species came
under the observation of Mr. F. A. Sirrine, who stated6b that work
was first observed in asparagus fields on Long Island in 1896. Late
in September, 1900, word was received of injury to asparagus from
Tennallytown, D. C. When the writer visited the field, although
injury was apparent on the outer skin of some stalks, no living
specimens could be obtained, only the dried puparia being in evidence
at that -time. October 2 of the same year, Mr. Samuel M. Bain,
University of Tennessee, Knoxville, Tenn., sent a stalk of asparagus
showing the work of this miner upon the skin, and, October 27,
specimens of the dried puparia.
February 18, 1901, it was reported at Philadelphia, Pa., that this
insect seemed to cause much greater trouble than the common
asparagus beetle. Two or three new beds of asparagus were lost on
account of its ravages.
By the writer's direction, Mr. F. C. Pratt visited a truck farm at
Brookland, D. C., where asparagus was one of the main crops, June
18, 1902. Asparagus was still being cut for market, but volunteer
plants were growing here and there in fields of corn, cantaloupe, and
potatoes, between rows. A few flies were seen on terminal shoots of
asparagus that showed wilting, and many volunteer plants were
badly infested, most individuals having transformed to pupae.
Although stems break off just below the ground, the entire colony of
insects below that point is left with sufficient moisture and nourish-
ment for their maintenance. The puparia were present in great
numbers underneath the outer skin of the root, and as many as nine
puparia were counted in a space only an inch long on one stalk. The
stalks below the point of injury appeared to be perfectly sound.
Larvae also were found in rotting stalks that broke off just below
During September, 1906, Messrs. J. B. Norton and A. D. Shamel,
of the Bureau of Plant Industry, furnished stems of asparagus from
Concord, Mass., showing severe infestation by this species, many
puparia being present under the mined outer skin. In the neighbor-
hood of Concord, a very important asparagus-growing region where
hundreds of acres are devoted to this crop, infestation was practi-
cally absolute, the insect being as abundant as the common asparagus
aBul. 10, n. a., Div. Ent., U. S. Dept. Agric., p. 62, 1898.
b Bul. 189, N. Y. Agric. Exp. Sta., p. 277, Geneva, 1900.


beetle, and present wherever rust was found, as also where no rust
was present. Some plants showed injury 7 inches below the surface.
Later Mr. Shamel reported finding infestation in every field and
patch of asparagus which he visited in Massachusetts and Connect-
icut, particularly at Suffield, Granby, and Hartford. Conn., and he
believed attack to be widespread.a
October 26, 1906, Mr. Ralph E. Smith wrote that the conditions
under which this asparagus miner was found in abundance in the
yellow stalks of asparagus in California, as reported by him in an
article on Asparagus Rust, Control,b had prevailed for two or three
years. The insect was always very abundant at the base of yellow,
dying stalks, although injury was attributed to the "centipede,"
reportedly as wireworms on a previous occasion.c
The asparagus miner was reported by Mr. I. J. Condit in the vicinity
of Antioclh, Cal., August 19, 1908, where the common asparagus beetle
was also abundant. The miner was equally numerous and stalks'
showing infestation were received. The miner-infested stalks could
generally be detected by their roughened appearance near the ground-
This species was also taken at Oakley, and it seems probable that it
is becoming generally distributed in California. In one place at
Oakley Mr. Condit observed the miner quite common on some stalks.
During October, 1908, the writer observed this species well estab-
lished on asparagus in the vicinity of Portsmouth, Va. In October,
also, very severe injury was reported to asparagus in the vicinity of
Concord, Mass. Tihe roots of the plants were not only girdled, but
the miners worked up the stalks some inches above the ground.


With our present knowledge of the life economy of this species,
two methods of control suggest themselves as of greatest value, and it
may be that they will prove all that is necessary under ordinary
(1) In spring permit a few volunteer asparagus plants to grow as
a trap crop, to lure the fly from the main crop or the cutting beds
for the deposition of her eggs. After this has been accomplished
the trap crop should be destroyed by pulling the infested plants and
burning them with their contained puparia. The time to pull the
plants will vary according to locality and somewhat according to
season also. The second and third week in June would be about the
right time in and near thei District of Columbia. On Long Island
this work should be (lone a week or two later. In the northernmost
a Its occurrence at New Haven, Conn., is recorded by W. E. Britton (6th Rept.
State Ent. Conn. for 1906, pp. 303-306, 1907).
b Bul. 172, Univ. Cal. Agric. Exp. Sta., p. 21.
CBul. 165, loc. cit.


range of this insect-for example, in Massachusetts-the last week of
June would be a suitable time.
These plants must be destroyed before the end of the cutting sea-
son, otherwise they are apt to provide abundant rust infection.
(2) The second generation can be destroyed in like manner by
pulling old infested asparagus stalks as soon as attack becomes mani-
fest and promptly burning them also.
If this work were carefully done over a considerable area, it would
leave little necessity for other methods, since it would do away with
these insects in the vicinity and leave few to be dealt with another
season; unless, indeed, this insect has an alternate food plant. Thor-
oughness and the cooperation of neighboring asparagus growers are
essential for success.
Secretary of Agriculture.
WASHINGTON, D. C., January 31, 1911.

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