Ground beetle larvae can reach a length of 114 inch. Ground beetle larva are beneficial and feed on other insects, including cutworms. They are not serious pests in terms of annual acreage infested, but they occur often enough to cause severe stand loss in some fields. The probability of crop damage from wireworms is low, except where corn follows a grassy situation such as pasture or CRP ground, or where problems have appeared during the past several years. Problems can persist in a corn field because wireworms live for two to six years.
Wireworms damage corn in several ways.
Early-season damage occurs when larvae bore into and hollow out the seed before or during germination. Death of seedling plants also can occur when wireworms tunnel into the seedling stalk. Some-times wireworms bore into the stalks of larger plants and tunnel several inches above the soil surface. True white grubs kill seedling plants by feeding on the roots. They have a three-year life cycle and can cause stand loss during the two years of their three year cycle.