Performance of Bt and Non Bt Cotton hybrids against pink bollworm, Pectinophora gossypiella

The experiment was conducted at Main Agricultural Research Station, Dharwad, during 2004–05 and 2005–06. In all the Bt cotton hybrids, the rosette flowers, larval population, green boll damage, locule damage were significantly low compared to their non-Bt cotton counter parts. Among all the Bt cotton genotypes, significantly lower pink bollworm larvae, green boll damage and locule damage were registered in RCH-2 Bt (5.6 larvae/50 bolls) being on par with RCH-20 Bt (6.4 larvae/50 bolls, 17.3% and 17.0%, respectively) and RCH-144 Bt (8.8 larvae/50 bolls). Significantly higher number of larvae, highest green boll damage and locule damage were recorded in DHB-290 (29.1 larvae/50 bolls, 39.3% and 34.5%, respectively) being on par with DHH-11 (25.4 larvae/50 bolls). The seed cotton yield among Bt cotton hybrids ranged from 6.7 to 10.3 q/ha, which was significantly superior to their non-Bt counter parts.