SB 818 e378 ENT Issued March 25, 1911. USS: DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY—CIRCULAR No. 135. L. O. HOWARD, Entomologist and Chief of Bureau. THE ASPARAGUS MINER. BY F. H. CHITTENDEN, Sc. D., In Charge of Truck Crop and Stored Product Insect Investigations. * WASHINGTON : GOVERNMENT PRINTING OFFICE : 1911 BUREAU OF ENTOMOLOG Y. L. O. Howarp, Entomologist and Chief of Bureau. C. L. Maruarr, Entomologist and Acting Chief in Absence of Chief. R. 8S. Ciirron, Executive Assistant. W. F. Tasret, Chief Clerk. F. H. Currrenpden, in charge of truck crop and stored product insect investigations. A. D. Hopkins, in charge of forest insect investigations. W. D. Hunter, in charge of southern field crop insect investigations. F. M. Wesster, in charge of cereal and forage insect investigations. A. L. QUAINTANCE, in charge of deciduous fruit insect investigations. E. F. Pariutpes, in charge of bec culture. D. M. Rogers, in charge of preventing spread of moths, field work. Roa P. Curris, in charge of editorial work. MABEL Co.corD, librarian. Truck Crop AND StoRED Propuctr INSECT INVESTIGATIONS. F. H. CuirrenDEN, in charge. H. M. Russet, C. H. Porpenor, D. K. McMizxan, E. G. Smyru, Tuos. H. Jones, M. M. Hieu, Frep. A. Jounston, Wm. B. Parker, H. O. Marsu, agents and experts. I. J. Connit, collaborator in California. P. T. Cotz, collaborator in tidewater Virginia. Il CirRcuLarR No. 135. Issued March 25, 1911. United States Department of Agriculture, BUREAU OF ENTOMOLOGY. L. 0. HOWARD, Entomologist and Chief of Bureau. THE ASPARAGUS MINER.? (Agromyza simplex Loew.) By F. H. Currrenpey, 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 isa 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. 79779°—Cir. 135—11 1 v4 THE ASPARAGUS MINER. The mines of the larve 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. DESCRIPTIVE. 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 toward the head. The puparium (fig. 2, d, e) is not unlike the ‘‘flaxseed”’ of the perni- cious Hessian fly, with which it has been aptly compared. At a little distance, also,it suggests a Lecanium scale. This stage is remarkable be- cause of its peculiar flattened and curved position, as seen from the Pe he estas mine Cages sm idle, Tt is red in color, and meas- acles; c, anal spiracles; d, puparium from side; UTreS about 3.5 mm. in length and e, same from above; /, section of asparagus : ae stalk, showing injury and location of puparia about 1 mm. in w idth. on detached section. a-e, Much enlarged: f, 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,? the locality being given as ‘‘ Middle States.”’ DISTRIBUTION. Tn its injurious occurrences this species appears to be limited to the eastern United States, from New England to Tennessee. From ayail- able data it is quite obvious, however, that it may be destructive over a considerable territory, 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. HISTORICAL AND BIOLOGICAL NOTES. In May, 1897, and afterwards this fly was observed in abundance by the writer on terminal shoots of asparagus, particularly at Cabin John, Md. Two weeks later no more flies were seen, but June 26 @ Diptera Americe septentrionalis indigena, Centuria octava 84, p. 160. THE ASPARAGUS MINER. 3 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.? 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 stated® 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.