r. S. D. A., B. K. Bill. 0»i. Part I. Issued March 16, 190" 



SOME INSECTS IXllRIOUS TO TRUCK CROPS. 



THE ASPARAGUS MINER. 



{Agromyza simplex Loew. ) 



The .stalks of asparagus arc freqiiontly attacked b}" insects, ana in 

 recent 3'ears have been reported considerably injured by the larva or 

 mag-got of a minute black fly to which the name asparagus miner has 

 been given. The larva mines under the epidermis of the stalk, and 

 when it has transformed to the puparium or "'llaxseed" 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 

 of the stalks and penetrates below the surface of the ground to a 

 depth of 7 or 8 inches. During the year 190f) this species attracted 

 considerable attention bv its abundance in some of the principal 

 asparagus-growing sections of New P^ngland and it bids fair to become 

 a pest of considerable importance. It was lirst noticed on asparagus 



Fig. l.—Agwmyza simplex: Fly, dorsal view at loft, lateral view at rislit. HiKhly magnified 



(or ginal). 



in 1896, ten years earlier than the present writing, prior to which 

 time nothing was known of its hal)its. It is a native species and evi- 

 dently restricted to asparagus as a food plant. Tntil the year Hmk; 

 it had not been recognized as doing injury to cutting beds, although 

 attack had been observed in various sections. The mine^; of the larvte 

 about and l)elow the bases of the stalks are fre(|uently so abundant 

 that they have the effect of girdling, so that the injured stalks can be 

 readily pulled from the ground. 



DESCRIPTIVE. 



The parent insect is a two-winged Hy (tig. 1), metallic black, with 

 large prominent head and e^-es, and clear wings, the wing expanse 

 being al)Out one-sixth of an inch (4 mm.). 



