Dynamically optimal strategies for managing the joint resistance of pests to Bt toxin and conventional pesticides in a developing country

In this study we discuss why planting non-Bacillus thuringiensis (non-Bt) cotton as a refuge crop in China (and other developing countries) may not be economically optimal. To show this, we develop a bioeconomic model to run simulations that will help find the optimal strategies for managing the joint resistance of pests to the Bt toxin and conventional pesticides. We show that the approach of not requiring non-Bt cotton as a refuge is defensible given initial conditions and parameters calibrated to China's cotton production environment. Of special importance is the existence of natural refuge crops. The nature of transaction costs associated with implementing a refuge policy is also considered.