Impact of Transgenic and Non-Transgenic Cotton on Insect Pests and Natural Enemies

The present field study was conducted at the Regional Agricultural Research Station in Lam, Guntur, to assess the effects of transgenic cotton on insect pests and associated natural enemies in comparison to non-Bt cotton. The findings showed that there was no difference in the egg-laying pattern of Helicoverpa armigera between Bt (12.68/plant) and non-Bt (13.07/plant). However, the number of larvae in the non-transgenic population was higher (6.33 larvae/plant) than in the transgenic population (2.30 larvae/plant). The boll damage caused by pink bollworm was lower in Bt cotton (27.68%) than in non-Bt cotton (36.33%). Populations of sucking pests, particularly leafhoppers, showed similar trends across Bt (15.82/three leaves) and non-Bt cotton (13.64/three leaves), with no major differences observed for aphids, thrips, or whiteflies. There were no discernible changes between transgenic and non-transgenic cotton in terms of natural enemies. Spider populations on Bt and non-Bt plants were 4.35 and 5.03 per plant, respectively. In contrast, the numbers of ladybird beetles and chrysopids were 1.12 and 1.39 per plant, respectively, in Bt cotton, while they were 0.93 and 1.10 per plant, respectively, in non-Bt cotton. The findings suggest that Bt cotton effectively suppresses bollworm infestation without negatively influencing the abundance of natural enemies, thereby supporting its continued role in integrated pest management.