The longer a field is in grass, the higher the infestation risk. Sampling methods and thresholds have not been established for white grub control. Generally, treat corn with a soil insecticide if adult beetles have been abundant in the field in previous years. Do this, particularly, if smartweed and velvet leaf have been common weeds and a preplant investigation reveals about one larvae per square foot. Wet weather coupled with matted, decomposing plants increases risk of this insect.
Seed treatments are the most economical management option.
Black cutworm-Damage from this pest is primarily dependent on spring weather and weed management. Stalk borer-Not to be confused with the European corn borer, its numbers are affected by previous years' weed types, such as grasses and ragweeds. Scout weed foliage just before planting or check emerging corn for damage or larvae on leaves. Apply a rescue type insecticide if 25 percent of emerging corn plants show leaf feeding. They can attain high levels of infestation in fallow areas and should be managed before crop emergence and when present in cover before planting.