THE CABBAGE MAGGOT 



W. D. Whitcomb, Research Professor of Entomologyi 



Although the cabbage maggot is native to Europe, it has been well known in 

 North Amerca for about one hundred years and has become so well established 

 in the northern part of this country that it is now recognized as one of the most 

 common and injurious Insect pests of the cruciferous vegetables. Cool, moist 

 weather favors the development of the cabbage maggot and it is most destructive 

 in the northern states and in Canada. Unpublished notes by Prof. Fred C. 

 Sears, formerly of the Massachusetts State College and a member of several 

 Grenfell expeditions, state that this insect is a very destructive pest of cruciferous 

 crops in Labrador. 



In Massachusetts the cabbage maggot is troublesome each year, and at Wal- 

 tham during recent years 70 to 80 percent of the untreated early cabbage and 

 cauliflower plants have been attacked regularly, with the infestation reaching 

 95 to 100 percent in favorable seasons (Figure 1). 



DESCRIPTION AND LIFE HISTORY 



The cabbage maggot fly, Hylemya brassicae Bouche, belongs to the family 

 Anthomyiidae. The flies of this family are frequently seen around flowers, and 

 somewhat resemble the common housefly. The maggots of most genera in this 

 family feed in living or decayed vegetable matter but a few are parasites in 

 living insects. 



The cabbage maggot has four stages of development: egg, larva or maggot, 

 puparium, and adult or fly (Figure 2). The most important characters are de- 

 scribed briefly. 



Egg 



Glistening white, oval in shape, about 1/25 of an inch long and one-third as 

 thick, with several longitudinal furrows on the surface (Figure 2-A). The eggs 

 are laid singly but are often found in groups in cracks and crevices in the soil 

 near the stem of the plants (Figure 3-A). 



Larva 



White, generally cylindrical but tapering to a relatively sharp point at the 

 head. At the rear or blunt end there are several tubercles of which two pairs 

 are large and more noticeable. Under favorable conditions the maggots become 

 full grown in about three weeks and are about 1/3 inch long, although their 

 size is dependent on the food supply and some are scarcely more than 1/10 inch 

 long when full}- grown (Figure 2-B). 



'Acknowledgments are gratefully given to Harold A. Wilson, Foreman, formerly Technical 

 Assistant; to William Garland, Technical Assistant; and to Wm. E. Tomlinson, Jr., Laboratory 

 Assistant, who did much of the field work reported in this bulletin. 



