Western and northern com rootworms are the most serious insect pests of non rotated com in the midwest (Levine and Oloumi-Sadeghi 1991). Adult female beetles lay the vast majority of their eggs in the soil of cornfields during August and early September, and the eggs lie dormant until hatching in the spring. Generally, very few eggs are laid in other crops. Because rootworm larvae cannot survive on roots of crops such as soybeans, alfalfa, or wheat, crop rotation is recommended to manage these pests. In fields where com is grown year after year, soil insecticides are typically applied to protect roots from rootworm feeding.