Challenges and successes in managing resistance of Spodoptera frugiperda (Lepidoptera: Noctuidae) to a low-dose Bt maize MON810

Transgenic maize expressing Cry1b protein from Bacillus thuringiensis Berliner (MON810) for managing Spodoptera frugiperda (J. E. Smith) has been approved for commercial release in Brazil since 2007. The adoption of Bt maize has increased significantly over time by reaching up to 90% of total maize-grown area during 2012/2013 agricultural season. In this paper we report the challenges and successes with the deployment of a low-dose event with demonstration of changes in susceptibilities to Cry1Ab in S. frugiperda populations and the effect on the performance of MON810 under field conditions. Understanding the spatial and temporal variability of different crops in major agricultural ecosystems is crucial for designing an effective Insect Resistance Management (IRM) program to Bt crops in Brazil.