New BT cotton prevents resistance
A major problem in managing BT cotton to prevent resistance is convincing farmers to plant non-BT seeds. Without the resulting refuges that allow development of susceptible pests, resistance inevitably development. Bruce Tabashnik, Yves Carriere, Xianchun Li and Chinese colleagues have discovered an ingenious strategy for eliminating resistance to the Bt toxins engineered into cotton to kill the pest, pink boll worm. The strategy used in China entails interbreeding Bt cotton with non-Bt cotton, then crossing the resulting first-generation hybrid offspring and planting the second-generation hybrid seeds. This produces a random mixture within fields of 75 percent Bt cotton plants side-by-side with 25 percent non-Bt cotton plants. That means refuge plants are mixed together with Bt ones and the cooperation of farmers is not needed.