The study, which looks at the characteristics of the moths that the larvae turn into, shows that a large majority of late-season moths in the Cotton Belt - specifically Helicoverpa zea, a major pest of cotton commonly known as the cotton bollworm - are not developing on cotton and soybean plants, as the prevailing theory suggests, but are developing instead on plants like corn.
The research suggests that this non-toxic corn, therefore, provides a major refuge for H. zea moths, and as such is critical to halting the evolution of insecticide-immune pests, perhaps more so than existing small cotton refuges.
The scientists published their work in Proceedings of the National Academy of Sciences.
Although it seems counterintuitive, non-toxic refuges are essential to controlling pests like the cotton bollworm because the pests that come from these refuges have little to no immunity to toxins. It is estimated that about 80 to 95 percent of cotton bollworms are killed by transgenic cotton plants that produce Bt toxin - derived from the bacterium Bacillus thuringiensis - leaving a fair number of potentially immune caterpillars moving about. When these immune pests mate with pests from non-toxic plants, offspring are not immune to the Bt toxin, and are likely susceptible to die a Bt toxin-induced death.
The scientists - including NC State's Dr. Fred Gould, William Neal Reynolds Professor of entomology, and Dr. Neal Blair, professor of marine, earth and atmospheric sciences; representatives from the USDA's Southern Crops Research Lab in College Station, Texas, and the Louisiana Agricultural Experiment Station in Bossier City,
Contact: Dr. Fred Gould
North Carolina State University