1a.Objectives (from AD-416):
Determine the susceptibility/tolerance/resistance of Heliothis virescens and Helicoverpa zea to Bt toxins.
1b.Approach (from AD-416):
Local crops grown by agricultural producers and experimental plantings of susceptible crops/hosts made by ARS will be monitored for occurrence of larvae. When available in sufficient numbers for bioassays, larvae will be collected during the growing season, placed in plastic cups containing diet, and shipped via overnight express to the locations where bioassays are being conducted.
The goal of this project is to facilitate the monitoring of resistance levels in field-collected Heliothis virescens (tobacco budworm) and Helicoverpa zea (cotton bollworm/corn earworm) to the Bacillus thuringiensis (Bt) toxin that provides insect control in certain genetically modified row crops including cotton and corn. During the FY 2013 growing season, H. virescens and H. zea larvae were collected from multiple garbanzo bean plots and corn fields, respectively, near College Station, TX. Between 70 and 400 larvae of each species were collected on multiple dates and placed in individual cups with diet. Immediately following each collection, larvae were shipped overnight to Tennessee or Georgia for use in larval feeding bioassays to quantify Bt-resistance levels. Project work has resulted in more than 2,000 larvae being assessed by the cooperator to help identify any changes in the level of Bt-resistance among H. virescens and H. populations in the central Texas area. As the work progresses, valuable information will continue to be gained relevant to resistance development of important crop pests to Bt toxins. The data will be critical in assuring that Bt technology in pest insect control remains viable well into the future. This project was scheduled to expire in FY 2013, but was extended through December 31, 2013.