Studies on the influence of Bollgard II Bt cotton (Cry 1Ac + Cry 2Ab) plants against I and II instar larvae of Spodoptera litura (Fab.)

Abstract

The present investigation was conducted at Regional Agricultural Research Station, Lam, Guntur, A.P. during kharif, 2014-15. To study the affect of BG II cotton plants against I and II instar larvae of Spodoptera litura. The mortality of 1st instar larvae of S. litura was recorded 100 % and 2nd instar larvae recorded 92.5 % on BG II hybrids, where as the mortality was very low and more or less similar in BG I and non Bt cotton hybrids 15-17 % and 10- 12% respectively. The mean weight of larva fed on BG II cotton leaves was found to be very low, where as BG I hybrids shows marginal influence and non Bt versions did not affect the larval or pupal weight and weight gains were more or less similar.