February, '16] SCHOENE: SEED-CORN MAGGOT 131 



THE ECONOMIC STATUS OF THE SEED-CORN MAGGOT 

 (PEGOMYA FUSCICEPS ZETT.)^ 



By W. J. ScHOENE, Blacksburg, Va. 



This insect is known as the seed-corn maggot, though it is said 

 to injure sprouting beans and peas, seed potatoes, and the roots of 

 cabbages and onions. The early history of the species has been 

 fully treated by Slingerland,- Chittenden' and others. P. fusciceps 

 attracted much attention during our study of the cabbage maggot 

 and at times it was difficult to tell from collections of adults which was 

 the more important species. There have been some specimens of 

 fusciceps in practically all our collections of adults of P. hrassicce, 

 the numbers varying with the season and the location where the flies 

 were captured. In one experiment in which the adults of hrassicce 

 were collected as they emerged from a badly injured cabbage seed-bed* 

 the males of this species constituted 23 per cent of the total number of 

 males. In sweepings of pea-fields or wild mustard, males of fusciceps 

 were frequently more numerous than those of the associated species. 



Because of the uncertainty of the part plaj'ed by this insect, some 

 efforts were made to ascertain its habits and to find its other hosts. 

 To that end many large fields of peas, beans and potatoes in Ontario 

 count}', New York, were examined for injured plants. However, 

 very few infested plants were found and for a period of eight years 

 only a few cases of injury were ever reported from that region, though 

 peas, beans and potatoes are among the principal crops. In spite of 

 our efforts, the importance of the insect was a matter of some doubt 

 until the following observations were made. 



During the autumn of 1911 a number of examinations of the crop 

 remnants of a cabbage field were made to secure material for breeding 

 experiments. The field in question contained a large number of 

 sprouted cabbage heads; that is, heads that had ripened and then 

 because of abundant moisture had put forth new growth. These 

 heads contained terminal sprouts eight to fifteen inches high. After 

 the head is broken it is no longer marketable, so these had been left 

 in the field after the crop was harvested and many of them had become 

 infested with maggots. Apparently the eggs had been deposited 



^ Contribution from the Department of Entomologj' of the New York State Exper- 

 iment Station, Geneva, N. Y. 



2 Cornell Agr. Exp. Sta. Bui. 78, p. 499. 

 » U. S. D. A. Ent. Bui. 33, p. 84. 

 «Jour. Eco. Ent. 4: 210. 



