Delia radicum
Fly larvae that tunnel into roots of cabbage family crops, causing wilting and plant death. Particularly damaging to young transplants.
Adults are small gray flies resembling houseflies. Larvae are white, legless maggots up to 1/3 inch. Eggs are white, laid at base of stems.
Wilting plants, especially on hot days. Stunted growth. Tunnels in roots. Secondary rot. Plant death. Blue-green leaf color.
2-4 generations per year. Adults emerge in spring, lay eggs at plant base. Larvae feed on roots for 3-4 weeks, pupate in soil.
Row covers immediately after transplanting. Rotate crops 3+ years. Remove and destroy infested plants. Fall tillage to expose pupae. Avoid planting near previous brassica crops.