Managing the Invasive Fall Armyworm through Biotech Crops: A Chinese Perspective

The first Bt maize in Brazil was launched in 2008 and contained the MON 810 event, which expresses Cry1Ab protein. Although the Cry1Ab dose in MON 810 is not high against fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), MON 810 provided commercial levels of control. To support insect resistance management in Brazil, the baseline and ongoing susceptibility of FAW was examined using protein bioassays, and the level of control and life history parameters of FAW were evaluated on MON 810 maize.

Abstract The rapid wide‐scale spread of fall armyworm (Spodoptera frugiperda) has caused serious crop losses globally. However, differences in the genetic background of subpopulations and the mechanisms of rapid adaptation behind the invasion are still not well understood. Here we report the assembly of a 390.38‐Mb chromosome‐level genome of fall armyworm derived from south‐central Africa using Pacific Bioscience (PacBio) and Hi‐C sequencing technologies, with scaffold N50 of 12.9 Mb and containing 22,260 annotated protein‐coding genes. Genome‐wide resequencing of 103 samples and strain identification were conducted to reveal the genetic background of fall armyworm populations in China. Analysis of genes related to pesticide‐ and Bacillus thuringiensis (Bt) resistance showed that the risk of fall armyworm developing resistance to conventional pesticides is very high. Laboratory bioassay results showed that insects invading China carry resistance to organophosphate and pyrethroid pesticides, but are sensitive to genetically modified maize expressing the Bt toxin Cry1Ab in field experiments. Additionally, two mitochondrial fragments were found to be inserted into the nuclear genome, with the insertion event occurring after the differentiation of the two strains. This study represents a valuable advance toward improving management strategies for fall armyworm.