Cabbage Root Maggot

This fly resembles a common house fly although it is somewhat smaller. It is gray with three distinct black stripes on the thorax, a dark stripe along the top of the abdomen, and is 5 to 6 mm long. The eyes are reddish-purple. Eggs are white and about 1 mm long. Larva are white, legless and have a pointed head. They grow to a length of 6 mm. Pupa are about the size of the adult and enclosed in a hard brown puparium. The Cabbage Root Maggot is most injurious in Canada and the northern U.S. It feeds primarily on crucifers such as cabbage, cauliflower, broccoli, brussel sprouts, collards, kohlrabi, radish, and turnip. Cabbage maggots eat small fibrous roots and tunnel in stems and large fleshy roots. If severe damage has been done, plants may wilt and die during the heat of the day. Infestations are difficult to detect in radishes and turnips because the tunneling of maggots in these large-rooted crops does not cause the foliage to wilt. Cabbage Root Maggots overwinter as pupae 2 to 13 cm deep in the soil. As the soil warms in spring, adult flies emerge from cocoons, feed on the nectar of flowers, and mate. Appearing as early as April, females soon begin depositing eggs in the soil at or near the base of host plants.

Photos courtesy the Canola Council of Canada.

For control products and more information please see our Fly Control page.