Beginner

Scientific Name
Delia platura

Identification
The translucent white maggots are small (< 5 mm), legless and oblong-shaped with a pointed anterior. The adult seedcorn maggot is a small (5 mm) grey-black fly.

These small white maggots feed on the swollen, ungerminated seed of vegetable crops and occasionally potato seed pieces.

Often Confused With
N/A

Period of Activity
Maggots may become a problem during cool, wet springs. The first generation of adult flies lay their eggs from April until the middle of June. There are several generations per year in Ontario; the first generation is generally the most damaging to potatoes.

Scouting Notes
Seed corn maggots are attracted to decaying seed tubers. Check areas of fields where crop emergence is poor.

Thresholds>
Not established. It is a sporadic pest in Ontario.

Advanced

Scientific Name
Delia platura

Identification
The translucent white maggots are small (< 5 mm), legless and oblong-shaped with a pointed anterior. The adult seedcorn maggot is a small (5 mm) grey-black fly.

These small white maggots feed on the swollen, ungerminated seed of vegetable crops and occasionally potato seed pieces.

Often Confused With
N/A

Biology
Life stages: eggs, larvae, pupae, adult flies.

Occasionally, the seed corn maggot is a pest of potatoes. Seed corn maggots over winter as pupae in the soil. The adults emerge in early spring. Adult females lay eggs in the soil, either on decaying organic matter or seed pieces. Larvae hatch in 7- 10 days and attack the seed piece through wounds or decaying tissues. Larvae may be active at soil temperatures as low as 10°C (50°F). There are 3- 6 generations per year.

The maggot may spread bacterial soft rot. Damage is usually more severe during cool, wet springs in soils with high organic matter content.

Period of Activity
Maggots may become a problem during cool, wet springs. The first generation of adult flies lay their eggs from April until the middle of June. There are several generations per year in Ontario; the first generation is generally the most damaging to potatoes.

Scouting Notes
Seed corn maggots are attracted to decaying seed tubers. Check areas of fields where crop emergence is poor.

Thresholds>
Not established. It is a sporadic pest in Ontario.

Management Notes
Incorporate winter cover crops well in advance of planting.

Populations are usually very low. No chemical control is required.