The cabbage maggot is the larva of a gray fly that is about 3/16" long. Females lay eggs near the base of plants such as cabbage, broccoli, cauliflower, radish, and turnip. The white larvae make tunnels and grooves in the roots and underground portions of stems. Soft rots may infect these areas, causing further damage. The leaves of affected plants are often yellow and stunted. Severe damage can result in wilting and death of plants. Younger plants are more severely damaged. Mature larvae are up to 3/8" in length. They pupate in the soil, with up to three generations occurring in a season. The last generation of the season overwinters in the soil, hatching into adults in early spring.

Management Options

Non-Chemical Management

Rotate crops. Do not replant susceptible crops in areas infested the previous year.
Cover crops with floating row covers or screen cages prior to emergence of adult flies to prevent egg-laying. Do not put row covers in areas previously infested with these maggots.
Plant older seedlings, which may tolerate damage better than young plants.

Select non-chemical management options as your first choice!

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

None recommended

Images

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Caption: Cabbage maggot damage on turnip Photo by: A.L. Antonelli
Caption: Cabbage maggot larvae Photo by: Unknown

WSU Extension

Hortsense