Modeling the evolution of resistance in cotton bollworm to concurrently planted Bt cotton and Bt maize in China

Transgenic maize expressing toxins derived from the bacterium Bacillus thuringiensis (Bt) may be commercially planted in northern China where Bt cotton has been for more than two decades. While brings additional benefits insect control, it complicates resistance management of bollworm (CBW), Helicoverpa armigera (Lepidoptera, Noctuidae), a common target and maize. Here we developed two-locus population genetic models to assess risk CBW which four cases types refuges are considered. Model simulations showed that time (TTR) is longest case two-toxin & maize, followed by one-toxin With 25% seed mixed refuge 20% refuge, TTRs order 54, 13, 9, 7 generations, respectively. natural refuges, differences among greater. Sensitivity analysis parameters examined, initial frequency alleles fitness cost ones most least sensitive, We concluded when scarce, planting both instead necessary combat concurrently China.