Investigating Action Thresholds and Alternative Approaches for Managing Helicoverpa zea in Cotton
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Helicoverpa zea is a major target of pyramided Bt cotton and Bt corn in the U.S. Over the past three years, growers, agricultural consultants and state Extension professionals have been reporting increasing incidences of H. zea surviving and injuring Bt corn and cotton in the southern U.S. There have been a number of reports of H. zea resistance to Cry1 and Cry2 Bt proteins. Subsequently, southern U.S. cotton producers have found it necessary to treat Bt cotton with insecticides to prevent economic losses to H. zea. However, there is a great deal of confusion among growers and Extension personnel regarding proper implementation of action thresholds and IPM approaches. This proposed work will evaluate and refine current H. zea threshold recommendations in cotton in the southern U.S. and how implementation of each threshold impacts control and cost effectiveness. We will investigate the potential for utilizing grain sorghum as a H. zea trap crop and nursery crop for natural enemies of H. zea and HearNPV inoculum for horizontal and abiotic transmission into cotton. Because the project also incorporates utilization of HearNPV in sorghum, data generated will have direct application to H. zea management in sorghum as well. Additionally, we will develop research-validated multi-channel Extension and outreach programing materials for H. zea treatment decision making and biological control enhancement in cotton.