Transgenic-Bt and Non-transgenic Cotton Effects on Survival and Growth of Helicoverpa armigera

The impact of Transgenic Bt cotton line (IR-FH-901) containing Cry1Ac toxin on Bt cotton leaves and flowers-bolls against Helicoverpa armigera Hubner with its parental non-Bt cotton variety (FH-901) was investigated. The parameters measured were larval mortality to pupation, larval period and pupal weight. Results indicated significant effects of Bt cotton on the percent cumulative mortalities of all instars compared with non-Bt cotton. However, a significant higher mortality (100%) was observed in neonates fed on Bt cotton leaves than those fed on Bt flower-bolls (93%). There was a marked difference in larval development period between Bt cotton (27.75 days) and on non-Bt cotton (16.68 days) flower-bolls. Pupae weight was significantly higher for larvae fed on non-Bt cotton compared with Bt cotton plant parts (leaves & flowers-bolls).