Abstract

The deployment of crop varieties that are partially resistant to plant pathogens is an important method of disease control. However, a trade-off may occur between the benefits of planting the resistant variety and a yield penalty, whereby the standard susceptible variety out-yields the resistant one in the absence of disease. Therefore, there is likely to be an optimal trade-off and thus an optimal cropping density for the resistant variety. I study a simple stochastic, epidemiological model to investigate the trade-off and the consequences for crop yield. I will discuss SIR epidemic dynamics and use the final size equation to calculate the surviving host population in order to analyse the yield, an approach suitable for rapid epidemics in agricultural crops.