LABORATORY EVALUATION OF TRANSGENIC BT COTTON AND NON BT COTTON PLANT PARTS AGAINST THIRD INSTAR LARVAE OF SPODOPTERA LITURA (FAB.) (NOCTUIDAE: LEPIDOPTERA)

Abstract

ABSTRACT The lab performance of certain released Bt cotton hybrids for their effect on Spodoptera litura were evaluated in comparison with non Bt cotton plant parts. Bt cotton hybrids viz., Bt bunny, six Bollgard II (cry 1 Ac + cry 2 Ab genes) hybrids e.g. RCH 2 Bt , RCH 515 Bt , RCH 596 Bt, RCH 530 Bt, RCH 134 Bt and RCH 533 Bt and two non Bt cotton viz., Non Bt bunny and RCH 2 non Bt cotton against cotton leaf worm, S. litura third instar larva. Four plant parts viz., young green bolls, top fully opened young leaves, middle leaves and squares were tested. Among the Bt cotton hybrids and non Bt cotton evaluated, RCH 2 Bt top fully opened young leaves showed highest per cent mortality followed by squares, middle leaves and young green bolls observed at 168 hours after the treatments (HAT) followed by top fully opened young leaves, squares, middle leaves and young green bolls of RCH 515 Bt which recorded 46.67, 38.34, 37.67 and 30.00 per cent mortality, respectively after 168 HAT when compared to squares, green bolls, top fully opened leaves and middle leaves of RCH 2 non Bt cotton which recorded 4.83, 4.17, 3.33 and 0.00 per cent mortality respectively after 168 HAT.