ABSTRACT

Bollworm, Helicoverpa zea (Boddie), production from various crop hosts was measured in 2002 by weekly larval monitoring in commercial crop fields and side-by side plantings to determine if temporal and spatial production of H. zea from various crop hosts are effective for B. t. resistance management. Pheromone trap catches demonstrated that H. zea production in localized areas had little impact on the number of H. zea moths in the local environment, which suggests a high level of movement by H. zea adults. Results from larval monitoring in commercial fields and a small plot trial demonstrated the potential for alternate crop hosts to produce much higher numbers of H. zea larvae and adults compared to Bollgard® cottons. Bollgard cottons produced the fewest number of larvae in six of six weeks for commercial field monitoring and four of five weeks for small plot trial monitoring. Therefore, results show that temporal and spatial production of H. zea by various crop hosts favor B. t. resistance management and that alternate crop hosts can effectively supplement the 5% unsprayed cotton refuge for Bollgard and Bollgard II® cottons.