Background:

The seed corn maggot is known to be an early season pest of corn. It is also common with fields that have manure applied to them, or the field has reduced tillage and decaying residue. This maggot is yellowish-white and found trying to burrow itself into the corn seed. Adult maggots will have no legs, and will be right around ¼ inch long, narrow, cylindrical and tapered. They will have a tiny black mouth containing hooks in the front and will not have a head.

 

Scouting and Damage:

Scouting is usually initiated when poor stands and emergence has been noted. Be sure to dig up the seed to make sure that maggot damage is present before diagnosing it. The maggot destroys the germ by working its way into seed and feeding on it. The seed simply cannot produce and germinate and leave gaps in the soil. If a seedling that became infested and somehow germinated, the seedling is very weak and will die. Any field that is heavily manured, is very attractive to egg-laying flies during the spring.

 

Time of Attack:

Planting until mid June VE-V4

 

Management:

No rescue option is available for the seed corn maggot besides replanting. Determine if replant is needed by the remaining population of healthy plants and yield expectation. Seed treatment is recommended if replant is going to be done before June. 

 

Sources:

Purdue Field Crops IPM

Iowa State Crops and Soil Resources