Abstract
The corn earworm, Helicoverpa zea (Boddie), is a common lepidopteran pest of corn (Zea mays L.) in the United States. This article provides an overview of the life history, ecology, plant injury, and management of H. zea in corn. Leaf injury by H. zea feeding can occur in vegetative stage corn, though this type of injury is rare. The most common type of injury is caused by larval feeding in ears. Because kernel injury is typically limited to the tip of the ear, H. zea is generally not considered an economic pest. The use of transgenic corn hybrids expressing insecticidal Cry proteins from Bacillus thuringiensis (Bt) Berliner can reduce injury from H. zea, though complete control is not achieved with most Bt traits. Resistance has been reported to several Bt toxins. Because H. zea is a major economic pest in cotton (Gossypium hirsutum L.) and because H. zea moths that developed on corn can migrate to cotton, selection pressure on H. zea in Bt corn has major implications for the pest status and injury to Bt cotton. Although the impact of H. zea on yield of field corn is generally negligible, the selection pressure exerted by Bt corn has led to management issues in cotton.
EVALUATION OF SELECTED BT CORN HYBRIDS (MON810) FOR CONTROL OF CORN EARWORM, 2001