STUDIES ON DEVELOPMENT AND SURVIVAL OF SPODOPTERA LITURA ON BT COTTON (CRY 1 AC) UNDER LABORATORY AND FIELD CONDITIONS
Central Institute for Cotton Research, Regional Station, Sirsa-125055 National Centre for Integrated Pest Management, LBS Building, New Delhi Directorate of wheat Research, Karnal (Haryana)-132001
M.C.JAT, P. JEYAKUMAR , D. MONGA, R. K.TANWAR AND O. M. BAMBAWALE
Seven cotton genotypes including four Bt cotton hybrids (RCH-134, RCH-317, MRC-6301 and MRC-6304) and three non-Bt cotton hybrids (RCH-134, RCH-317 and LHH-144) were screened for feeding preference by Spodoptera litura (Fabricius) studies under laboratory and field conditions. Weight gain in larvae of S. litura was more when fed on RCH-134 bt (101.45 mg /larva) with relative growth rate (RGR) of 4.29 / larva as compared to its non-Bt counterpart (53.71 mg /larva and RGR 2.51/larva) under laboratory conditions. In the field, incidence of S. litura showed an increasing trend and reached maximum (0.80 larvae/plant) in RCH-317 Bt cotton on the 41st Standard Meteorological Week (SMW). The pooled data indicated that the population of S. litura ranged from 0.06 to 0.40 larva per plant in all the Bt cotton hybrids as against 0.05 to 0.12 larva per plant in non-Bt hybrids.