Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 12/22/2003
Publication Date: 1/6/2004
Citation: Blanco, C.A., Adams, L.C., Carroll, S., Hardee, D.D., Gore, J., Greene, J.K., Herbert, A., Johnson, D., Karner, M., Leonard, R. 2004. Bacillus thuringiensis resistance monitoring program for tobacco budworm and bollworm in 2003. National Cotton Council Beltwide Cotton Conference. 1327-1331 Interpretive Summary: Advances in biotechnology have created cotton plants (transgenic) that produce their own insecticide. This form of pest control is safe for the enviroment and farm workers, innocuous to human health and in many cases economically advantageous. Early detection of pest immunity (resistance) to transgenic cotton-producing toxin (Bacillus thuringiensis) is a way to preserve this important technology. Monitoring these changes of immunity in important cotton pests (tobacco budworm and bollworm) has been mandated by the U.S. Environmental Protection Agency to companies that market transgenic cotton and this effort offers an opportunity to make sound decisions by the USDA, EPA and industry. Since 1996, the ARS Southern Insect Management Research Unit in Stoneville has shouldered the responsibility of monitoring for resistance in the cotton belt by implementing a method that accommodates multiple tests performed with moths coming from 14 different states in the U.S. shipped by more than 20 researchers/cooperators. In 40 tests performed with tobacco budworm populations and 97 bollworm populations we were not able to detect signs of resistance utilizing this particular method. Limitations, additions and modifications to the previous methodology are discussed in this report.
Technical Abstract: A national program, conducted in 14 cotton-producing states, with the goal of monitoring the susceptibility of Heliothis virescens and Helicoverpa zea to the protein Cry1Ac of Bacillus thuringiensis was conducted for the eighth consecutive year in 2003. A methodology that evaluates the survivorship of the first generation of larvae obtained from the mass mating of males captured near cotton fields in pheromone traps (wild population) and laboratory adapted females (susceptible strain), utilized 2 diagnostic doses per insect species plus an untreated control dose. This method, considering its limitations of only detecting dominant resistant gene(s), demonstrated no sign of resistance in 40 strains of Heliothis virescens and 97 strains of Helicoverpa zea obtained between April and October. Additions and modifications to the previous methodology are discussed.