Wireworms infest corn throughout Iowa but are not a serious pest statewide in terms of acreage infested. However, economically significant populations can lead to severe damage in local areas anywhere in Iowa. Overall, the probability of a field suffering damage from wireworms is very low, except where the crop follows perennial grass stands, including pastures and CRP, or where problems have occurred in the past few years. Seedling plants also can be injured or killed by larvae tunneling into the plant below the soil line. Occasionally, wireworms bore into the stalks of larger plants and tunnel in a few inches, but the damage is not significant.
Seedcorn maggots are occasional pests of both corn and soybean seeds at germination.
They are more of a problem in soybean than in corn. Yield reduction occurs because of stand loss and damage is more likely in cool, wet springs when the seeds are slow to germinate but the insects are still actively feeding. The greatest potential for seedcorn maggot damage exists when weeds or fresh animal manure are incorporated into the soil just before planting. Decaying material attracts the adult flies where the females lay eggs. Slender seedcorn beetle.