Seedcorn Maggot

Delia platura

Seedcorn Maggot is a species-level seed and seedling maggot associated with germinating seeds, cotyledons, seedlings, and fields rich in decaying organic matter. Seeds fail to emerge, cotyledons are hollowed, and seedlings collapse before or shortly after emergence. The biology determines the sampling route.

Identification

Larvae are small cream-colored maggots that enter swollen seed or young seedlings. Adults are gray flies resembling small house flies. Dig missing-row sections, recover damaged seed, and inspect for maggots or brown puparia. Compare with poor seed vigor, cold injury, and damping-off. Use a specimen with host tissue.

Symptoms / Signs

Seeds fail to emerge, cotyledons are hollowed, and seedlings collapse before or shortly after emergence. Confirm fresh activity directly. Old injury may persist.

Life Cycle / Process

Seedcorn Maggot undergoes complete metamorphosis. Egg placement occurs on or within germinating seeds, cotyledons, seedlings, and fields rich in decaying organic matter; larval feeding and pupation follow before adult emergence. Prevention targets adults or eggs.

Prevention

Inspect incoming material tied to germinating seeds, cotyledons, seedlings, and fields rich in decaying organic matter, remove relevant culls and reservoirs, and maintain sanitation in the work area. Match exclusion and sanitation to Seedcorn Maggot rather than using one fly procedure across all records. Primary prevention target: Seedcorn Maggot on germinating seeds, cotyledons, seedlings, and fields rich in decaying organic matter.

Management / Control

Allow incorporated organic matter to decompose before planting, use vigorous seed, avoid planting into cold wet soil, and use labeled seed protection only where justified. Use official controls for regulated detections. Recheck living stages.

Procedure Steps

1. Recover failed seed and seedlings from the missing-row section with an unaffected comparison. 2. Recover larvae or adults and record the exact feeding site. 3. Close the Seedcorn Maggot incident only after new injury stops.

Safety Notes

Use gloves and eye protection when sampling germinating seeds, cotyledons, seedlings, and fields rich in decaying organic matter or handling pesticide-treated tissue. Confirm the Seedcorn Maggot label, harvest and worker intervals, pollinator language, bait use, and lure restrictions.