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 which provides insect control in certain genetically modified row crops, including cotton and corn. In FY 2011, larvae of these two insect pests were collected from three geographically distinct locations in Texas. More than 200 larvae of each species were collected and placed in appropriately labeled individual sampling cups, with diet. As soon as possible after each collection, the larvae were overnighted to the cooperator's facilities in Tennessee so that Bt resistance bioassays could be conducted. Work under this project, overall, has facilitated the collection of important data on Bt resistance in heliothine insects; the data will be utilized in development of use protocols to assure that transgenic crops protected by the Bt toxin remain viable in world agriculture for as long as is reasonably possible. This project was scheduled to expire in FY 2011, but was extended through 09/30/2012.