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 in field-collected Heliothis virescens (tobacco budworm) and Helicoverpa zea (cotton bollworm/corn earworm) to the Bt toxin that provides insect control in certain genetically modified row crops, including cotton and corn. During the 2012 growing season, Heliothis virescens and Helicoverpa zea larvae were collected from three fields near College Station, Texas. More than 400 larvae of each species were collected and placed in individual sampling cups with diet for each field and collection date. Immediately following each collection, larvae were shipped overnight to Monsanto's facility in Tennessee for use in larval feeding bioassays that quantified resistance to Bacillus thuringiensis (Bt) toxins. This work has resulted in two scientific presentations at the Beltwide Cotton Conferences. Project work has resulted in more than 1,000 larvae being assessed by the cooperator to help identify any changes in the level of resistance to Bt toxins of Heliothis virescens and Helicoverpa zea populations in the College Station area. This project was scheduled to expire in FY 2012, but was extended thru September 30, 2013.