To date, no economic populations of rootworm eggs ever have been shown to survive in the soil for more than two growing seasons. Damage due to corn rootworm larvae can range from slight to total loss of yield depending on infestation levels, moisture availability, soil type, and root characteristics of the corn hybrid planted. Adult corn rootworms are beetles about a quarter-inch long and primarily feed on silks, pollen, and ears of corn. Northern corn rootworm beetles are uniformly green to yellow green in color. Western corn rootworm beetles are tan in color with two to three black stripes on their wings.
Beetles lay eggs in the soil from late summer to fall.
Eggs overwinter in the soil then hatch in the spring. Variants of the western corn rootworm that appear to have circumvented crop rotation by laying eggs directly on soybean fields have not been found in South Dakota or Nebraska, Catangui said. To date, these variants have only been documented in certain regions of Indiana, Illinois, Ohio, Michigan, and eastern Iowa, he added.