Cabbage maggots can cause damage all summer long. Eggs hatch in one to nine days, depending on the soil temperature. Larvae develop rapidly with warm temperatures. Within one to three weeks mature maggots pupate. Adult flies emerge approximately one to three weeks later.
Prevention is the best management strategy.
This allows the maggots to mature and pupate. When rotating into a field with crop residues cannot be avoided, it is best to treat with a commercial seed protectant insecticide. Organic growers can cover the field with floating row cover to exclude the adults of cabbage maggots. However, seedcorn maggots, because of their varied diet, may already be present in the soil and can attack seeds under floating row covers. The adult flies may travel several miles to find a suitable host.