Extension > Garden > Diagnose a problem > What insect is this? > Garden Pests > Caterpillars, maggots, grubs, and similar immature insects - Under than 1/4 inch long > Root maggots (onion and cabbage maggots)
Root maggots (onion and cabbage maggots)
Whitney Cranshaw, CSU, Bugwood.org
Size: Up to 1/4 inch long
Where/When: Feeds on the roots of onion and several crucifer plants, including broccoli, radishes, cabbage, cauliflower, and turnips. Activity starts in late May and continues for 4 weeks. Larvae are rarely, if ever, seen.
Significance: Infested plants can appear discolored, wilted, or stunted and damage may kill young plants.