Predators delay pest resistance to Bt crops
The results showed that diamondback moth populations were reduced in the treatment containing ladybird beetles and unsprayed non-Bt refuge plants. Also, resistance to Bt plants evolved significantly slower in this treatment. In contrast, Bt plants with no refuge were completely defoliated in treatments without ladybirds after only four to five generations, showing rapid development of resistance in the pests. In the treatment with sprayed non-Bt refuge plants and predators, diamondback moth populations were reduced, but the larvae more quickly evolved resistance to the Bt plants.
“These results demonstrate the effectiveness of Bt plants in controlling the pest population, the lack of effect of Bt on the predators and the role predators play in delaying resistance to Bt plants in the pest population,” said Shelton.
The study was funded by United States Department of Agriculture and the Special Research Projects for Developing Transgenic Plants in China.