Chemical control combined with transgenic Bt maize to control Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae)

In an attempt to improve the effectiveness of control of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) in Bt transgenic maize, we tested a combination of this strain with seed treatment and chemical control in the field. The trial was conducted in Ribeirão Preto, São Paulo, Brazil, with maize sown on 03/13/2013. The experimental plots (randomized blocks) were 4 rows of 6 m each, with 5 plants per meter and spacing of 0.7 m. The treatments tested were a combination of conventional and transgenic maize with seed treated with imidacloprid + thiodicarb (CropStar™) and chemical control at 15 days after seedling emergence, with lambda - cyhalothrin + thiamethoxan (Engeo™ Pleno). Twenty-five plants were artificially infested with neonate larvae of S. frugiperda (40 larvae per plant). At 15, 25 and 35 days after emergence, the plants were inspected for foliar injury, on a Davis scale from 0-9. On the last day, 10 plants from each plot were destroyed to count the number of larvae. Treating the seeds with insecticides applying insecticides to the plants, and a combination of the two did not improve the effectiveness of non-GM maize and GM maize Bt Cry1F PAT (Herculex™) and Cry1A.105 Cry2Ab2 Cry1F PAT EPSPS (PowerCore™) in the control of S. frugiperda.

Keywords: agricultural pest, insecticides, seed treatment.