Effect of BT and non-BT cotton on biology of Thrips tabaci and its management using insecticides

The development of Thrips tabaci was studied on transgenic BG I, BG II, non-Bt, and desi cotton cultivars. The oviposition period was minimum on desi cotton, FDK 124 (11.67 days) as compared to BG II (RCH 650) and non-Bt cotton (LH 2076). Female longevity was minimum on FDK 124 (17.50 days) followed by RCH 650 (23.17 days) and LH 2076 (21.83 days). Maximum female longevity was recorded on BGI cotton cultivar RCH 308 (26.83 days). Nymphal, pupal period, and total development period were minimum on FDK 124 (8.17, 2.33, and 34.00 days) as compared to Bt and non-Bt cotton cultivar, LH2076. Based on the higher oviposition period, female longevity, fecundity, and nymphal period, Bt cotton hybrids were found to be more favourable for thrips development in comparison to non-Bt cotton cultivars and desi cotton. The new generation insecticide, spinetoram 11.7SC @ 425g/ ha was most effective and also found to be safe to the predators.