By mid-July, most larvae have finished feeding and transformed into adult beetles. They emerge from the soil to feed, mate and lay eggs. These eggs produce the larvae that will attack the following year's crop. The adults prefer to feed on corn leaves. Once pollen shed is completed, they usually migrate in search of other pollen sources, such as later-planted fields or other pollen producing Crops.
Females start laying eggs when they are about two weeks old.
They prefer moist areas, so eggs usually are concentrated in the soil between the rows in irrigated corn. Heavier soils with organic matter content above 1.5 percent also are preferred. Adult root-worm feeding on silks has been thought to interfere with pollination and grain production. Studies under Colorado conditions have failed to show significant yield loss from as many as 20 beetles feeding on a single ear, so insecticide treatments to prevent such damage are not generally recommended. This is the most consistent and economical means of controlling rootworms.