Modeling durability of DAS-59122-7 maize efficacy against corn rootworm (Coleoptera: Chrysomelidae) when refuge is deployed as a seed blend

The model of Onstad (2006), investigating blended refuge for corn rootworm, was modified based on the unique characteristics of event DAS-59122-7. These characteristics and improved model parameter estimates are a result of research that has continued since the original US regulatory submission in 2003. Modifications include the addition multiple fields that can be modeled simultaneously, the ability of larvae to discriminate between protected and refuge roots and the addition of a gene inherent in rootworm populations conferring tolerance to maize containing DAS-59122-7. The model accurately predicted beetles per plant for both western and northern corn rootworm using different rates of blended refuge and also predicts genotypic frequency. The calibrated model was used to evaluate how the relative durability of CRW efficacy may change in response to different ecological, genetic and practical factors. The model and results of specific simulations will be presented.