Ovipositional preference of tobacco caterpillar, Spodoptera litura (Fabricius), to different transgenic Bt cotton cultivars

The ovipositional preference of S. litura on two Bollgard (Bt) cotton hybrids (Yuvraj and JKCH 1050), three Bollgard II hybirids (NCS 855, Ankur 3028 and MRC 7017) and one non Bt cotton cultivar (LH 2076) was studied on 105, 120 and 135 day old plants. Significantly higher number of S. litura eggs were recorded on Ankur 3028 BG II (140.77 eggs/plant) and MRC 7017 BG II (139.08 eggs/plant) as compared to NCS 855 BG II, LH 2076, Yuvraj and JKCH 1050. More number of eggs per plant was recorded at 135 day old plants (135.71 eggs/plant) as compared to 105 and 120 day old plants. The study on morphological parameters revealed significantly higher no. of trichomes on Ankur 3028 (36.26/mm²) and MRC 7017 (34.11/mm²) whereas significantly higher trichome density was observed in 135 day old plants (27.75/mm²). Trichomes from leaves of JKCH 1050 (730.96 μm) and Yuvraj (720.44μm) were significantly lengthier as compared to other cultivars.