Certainly one of the greatest successes of genetic engineering has been the insertion of genes from a bacterium called Bacillus thuringiensis that code for production of insecticidal proteins into the chromosomes of various crops. The resulting transgenic cotton, corn and potato plants contain bacterial genes. These plants produce insecticial proteins from seedling stage until harvest, effectively protecting the crops from specific pests without disrupting beneficial insects or wildlife. Insecticide use on these so-called Bt crops is reduced, which saves farmers money and helps protect the environment. But as is the case with other insecticides, insect pests can evolve resistance to Bt proteins. If that happens, farmers will lose a powerful tool and may have to return to conventional insecticides to protect their crops.
For 17 years, Dr. Fred Gould, William Neal Reynolds professor of entomology, has been studying how insects evolve resistance to Bt proteins and looking at ways to decrease the risk of rapid pest adaptation to Bt toxins. Indeed, Gould was among the first to show that insects could adapt to Bt crops. The detailed research findings of the Gould lab have been instrumental in convincing the Environmental Protection Agency and industry that there are ways to get long-term benefits from Bt toxin-producing crops. One of these ways is the planting of what have become known as refuges of non-Bt crops, crops that are susceptible to insect attack. Refuges help prolong the useful life of Bt crops by ensuring that an insect population continues to contain individuals susceptible to the Bt toxin. If these susceptible individuals breed with the initially rare, resistant insects, they can substantially decrease the rate at which the entire pest population becomes resistant. Most recently, Gould was involved in a study that suggested that late in the season, a large percentage of cotton bollworms, a major pest of cotton, are developing on plants like corn rather than on cotton, as had been thought. This work indicates that, at least for the bollworm, there are normally occurring refuges for susceptible individuals, so less cotton acreage needs to be devoted to non-Bt cotton.