Study on food consumption parameters of Spodoptera litura (Fab.) (Noctuidae: Lepidoptera) on different Bt cotton hybrid plant parts

The food utilization efficiency of Spodoptera litura (Fab.) on squares, flowers and bolls of Bt-II cotton hybrids was reduced compared to Bt-I hybrids. Bt-II cotton hybrids were found to be superior over Bt-I hybrids. Among the twelve hybrids tested the least consumption index (C.I.) on squares, flowers was recorded on RCH-2 Bt-II (5.30), (5.36) respectively, and least growth rate (G.R.) was recorded in NCS-950 Bt-II on squares, flowers (0.083) and (0.080) respectively. The lowest E.C.I was noticed in NCS-950 Bt-II (1.51) on squares. On flowers the least E.C.I was recorded in RCH-134 Bt-II (1.54) where as on bolls the E.C.I was least in NCS-954 Bt-II (1.51). The least E.C.D on squares was noted in NCS-954 Bt-II (17.75) on flowers least was in RCH-134 Bt-II (18.50), on bolls it was (20.14) in NCS-954 Bt-II which was least. The Approximate digestibility was recorded least in NCS-145 Bt-II (40.36) on squares, on flowers the least A.D. was noticed in RCH-134 Bt-II (48.73), whereas on bolls it was RCH-134 Bt-II recorded least A.D. as 47.91 compared to other hybrids.