Spatially explicit economic effects of non-susceptible pests' invasion on Bt maize

Abstract

Maize expressing the Bacillus thuringiensis Cry1Ab toxin (Bt maize) provides a more effective control of corn borers than the use of insecticides. Yet, the spatial expansion of Bt maize may offer ideal ecological conditions for the development and spread of secondary pests, i.e. pests not susceptible to the expressed toxin. This paper develops a bio-economic, spatially explicit population model to analyse the spread and economic consequences of a secondary pest outbreak. Results show that the present use and even an eventual expansion of Bt maize can be economically and environmentally advantageous, as it would decrease insecticide usage intensity. However, we show that caution is required when considering its widespread use. If a pest outbreak is not identified and dealt with at an early stage, it could lead to severe economic impacts even if insecticides are used in combination with the Bt maize. We further discuss potential policy and subsequent management strategies to address this issue.

An agent‐based model of insect resistance management and mitigation for Bt maize: a social science perspective

“…Also, economic surplus is an incomplete measure of social benefits 57 . For example, as used here, it ignores the environmental impacts of insect management, although a significant benefit of Bt maize is that it substitutes for conventional insecticides 58–60 . With these caveats, the policy experiments reported here support refuge requirements as the foundation of resistance mitigation policies for high‐dose technologies, just as for resistance management.…”