The pupal stage lasts about 2 to 3 weeks. Adults then emerge from the soil. Duration from egg to adult emergence is 6 to 8 weeks under field conditions. Corn earworm overwinters as a diapausing pupa in the soil and undergoes several generations each year. In the North, the pupa can survive only during mild winters.
Adults are strong fliers and, in the spring, are spread northward from warmer overwintering areas.
Infestations in greenhouses occur when the corn earworm moths fly through open doors, windows, and vents and then deposit eggs on the plants. Corn earworm larvae are cannibalistic. Chemical insecticides provide adequate control of corn earworm. For chemical control recommendations, consult the current Cooperative Extension Service publications on ornamental plant pest management.