Effect of Bt Cotton on Growth and Development of Pink Bollworm, Pectinophora gossypiella

The laboratory experiment was carried out during 2004-05 and 2005-06 at Department of Agricultural Entomology, Dharwad. The larval weight was less (5.6 to 26.2 mg) in Bt cotton, compared to non-Bt cotton (5.6 to 43.8 mg). When the larvae were reared on Bt cotton bolls there was gradual increase in the larval mortality from three days after release (DAR) (28.2%) to 12 DAR (56.3) during 2004-05 and 2005-06. The period taken for pupation was more (23.2 days) on Bt cotton compared to non-Bt cotton (18.8 days). The pupal weight was less on Bt cotton (18.2 mg) compared to non-Bt cotton (25.7 mg). The adults lived for shorter time in Bt cotton fed larvae compared to non-Bt cotton.