Under such conditions, high numbers of beetles survive the winter and attack the slowly growing corn over a prolonged period. Growth is retarded and leaves may wilt. Early maturing varieties in the middle and southern states are most seriously affected. Color plate . Life History - Adults generally overwinter in litter and trash around fields.
Mortality tends to be high during harsh winters.
In early spring, the beetles move to weeds and then to corn seedlings. Eggs are scattered on the soil beneath host plants. In about 10 days, the larvae emerge and begin feeding on and tunneling in underground stems, roots, or tubers. They feed for 3 to 4 weeks and develop through three instars before pupating in the soil. In 7 to 10 days, a new generation of adults emerges.