Impact of transgenic events on Helicoverpa armigera (Hubner) and Spodoptera litura (Fabricius) on cotton in India

Four Bt cotton hybrids viz, RCH2 Bt, JK Durga Bt, Nath baba Bt and RCH BG II representing Mon 531, JK cry1Ac, GFM and Mon 15985 events with their corresponding non Bt genotypes were evaluated under field conditions at RARS, Lam, India. The comparative incidence and damage of Helicoverpa armigera (Hubner) and Spodoptera litura (Fabricius) over two years revealed the superiority of Bt cotton hybrids in managing H. armigera. However, the incidence of S. litura is comparable in both Bt and non Bt hybrids except RCH BG II. This second generation Bt cotton hybrid was found superior over the other tested hybrids with no signs of incidence and damage of both target pests. Despite the low levels of damage on all Bt hybrids, little progression was observed after 130 DAS corresponding to decreased levels of toxin expression. The present investigation can be helpful for IPM in Bt cotton.