Biological parameters of the non-target pest Aphis gossypii Glover (Hemiptera: Aphididae) on genetically modified (GM) Bt cotton

In the present work, we aimed to evaluate: 1) the influence of the Cry 1Ac protein expressed by the genetically modified cotton variety (Bt) NuOpal, on the biological parameters of a non-target pest, Aphis gossypii, reared under laboratory conditions; 2) the influence of plant age on aphid development. Cotton cultivars were grown following technical advice. In the laboratory, the aphids were separated into plastic containers including a cotton sheet, which was changed daily with the help of a moist cotton cloth. Observations were carried out daily, and the duration of the immature and adult stages, and offspring number, were recorded. Our results show that regardless of the differences in the duration of each instar, cultivars Bt and non-Bt and the different ages of the plant to Bt, no differences were seen in the total duration of these phases. It was only during the reproductive period that differences were observed among genotypes for 120 days. Regarding the number of offspring and longevity total, there were differences between the different ages of the Bt treatment.