The wireworms that hatch from these eggs are thin, straw-colored larvae that may reach 4 mm in length. They feeds on the roots of the grass or any crop that may have been planted in the field. Wireworms most often attack the germinating seeds destroying the seedlings before emergence. However, this insect may also feed on the roots and lower stems of emerged plants causing them to wilt and die. The wireworm requires 2 to 5 years to complete its life cycle.
Crop damage is often the most severe in the second crop year following grassy sod.
The wireworms feed on the remains of the sod during the first year, but in the second year, the crop seedlings provide the only source of food. Seed treatments containing an insecticide offer some protection to the seed against this insect. However, seed treatments give little protection to the plant after emergence. Some of the insecticides used to control corn rootworm larvae also control wireworms. The seedcorn maggot is a small whitish larva that reaches a maximum size of about 7 mm.