The seedcorn maggot is yellowish white and about 1/4 inch when mature. The body is legless with a pointed head and a blunt tail. The brown pupae cases are hard and football-shaped and are found in the soil near the roots. The adult seedcorn maggot resembles a housefly with dark gray wings and 3 stripes on its back. (SOURCE: University of Kentucky, Seedcorn Maggots, Ric Bessin)
Damage from Seedcorn Maggot
Although the seedcorn maggot feeds primarily on decaying organic matter, they also will feed on seeds and seedlings of soybeans and field corn. Damage may range from a few meandering tunnels in the seeds to the entire contents of the seed destroyed.
Seedcorn maggots damage corn by feeding inside the kernel, resulting in failed germination or emergence of a weakened seedling. Any condition that delays germination results in more exposure of the seed to attack. Cold, wet soils are therefore more likely to result in injury.
Fields with decaying organic matter near the surface are at risk of infestation by seedcorn maggots. This includes recently plowed or disked cover crops or weeds, or recently manured fields.
Life Cycle of Seedcorn Maggot
Seedcorn maggots overwinter as pupae. When soil temperature increases, the adults emerge, mate and search for a host plant to lay their eggs. After the eggs hatch, the seedcorn maggot feeds on organic material in the soil. After feeding, the larvae enter the pupae stage. (SOURCE: University of Kentucky, Seedcorn Maggots, Rick Bessin)
Management of Seedcorn Maggot
If seedcorn maggots are suspected, carefully dig up the seeds in the row skips and examine them for evidence of seedcorn maggot damage. After damage is observed on the crops, rescue treatments are not usually effective. If the damage is severe, replanting may be necessary.
Soil-applied insecticide or planter box seed treatment may protect the seed from seedcorn maggot feeding.
Fields with decaying organic matter near the soil surface are at risk of infestation by seedcorn maggots. This includes recently plowed or disked cover crops or weeds, or recently manured fields.