THE MONTHLY BULLETIN. 



251 



THE ASPARAGUS MINER. 



Agromyza simplex Loew (Family Agromyzidis). 

 (Fig. 247.) 



General Appearance. — The adult flies have a wing expanse of about 

 one-sixth of an inch and are metallic-black in color. The maggots are 

 one fifth of an inch long and white. The puparia are one seventh of 

 an inch long and red. 



Life History. — The first adult insects appear early in the spring, 

 other broods appearing later. The larvge mine beneath the epidermus 

 of the stalks near the bases and may penetrate eight inches under- 

 ground. The injury is often so severe as to completely girdle the stems 

 and thus do much damage. The puparia are formed in the burrows, 

 especially on the roots and bases of the stalks. There are at least two 

 generations each year. 



Fig. 24 7. — The asparagus miner {Agromyza simplex Loew). Adult flies at left 

 and immature forms at right as follows : a, larva, lateral view ; b, thoracic spiracles, 

 and c, anal spiracles of larva ; d, side view and e, top view of puparium ; f, section 

 of asparagus stock, showing injury and location of puparia. All much enlarged 

 except f which is slightly reduced. (After Chittenden.) 



Distribution. — This fly has been reported by Mr. I. J. Condit of the 

 United States Department of Agriculture at Antioch, in Contra Costa 

 County, and at Oakley. It appears to be generally distributed in the 

 central part of the State. 



Food Plant. — This pest works only upon asparagus plants. 



Control. — The control of the fly is somewhat difficult and consists 

 in the use of trap crops early in the spring, which should be removed, 

 roots and all, and burned in June. Other traps should be allowed to 

 grow up immediately' and similarly destroyed in the fall. 



Ciitting out all infested stalks as often as they appear is also advis- 

 able. 



