Root maggots attack cabbages, onions, carrots, and radishes.
Adult root maggots look like small houseflies. The larvae/maggots are white to yellowish-white in color and legless.
Damage Caused by Root Maggots
Root maggots attack onions, carrots, cabbages, and other root crops. Heavily infested plants turn yellow, and their roots have numerous tunnels made by the maggot while feeding on the roots and in the case of onions on the bulbs.
Life Cycle of the Root Maggot
Adults lay eggs in cracks in the soil or plant stems at soil level. The maggots feed for 3-4 weeks on roots. The root maggots tend to have about three generations in Illinois particularly the onion maggot. Root maggots overwinter as pupae in the soil.
Management of Root Maggots
There are natural enemies of root maggot larvae such as ground beetles and other predators such as tiny wasps. Red varieties of cabbages are resistant to cabbage root maggots, disk/rototill crop residues underneath the soil immediately after harvest to reduce overwintering sites. Rotate onions with other crops to control onion maggots.
Insecticides can be used to manage root maggots. Contact your county Extension office for current pesticide controls.