41st Annual Meeting of the Society for Invertebrate Pathology
and 9th International Conference on Bacillus thuringiensis

Spodoptera litura is a major pest attacking important commercial crops like cotton in India. Commercial Bt cotton hybrids carrying Cry1Ac toxin (Bollgard I type) or Cry1Ac and Cry2Ab toxins (Bollgard II type) give adequate control of the target insect Helicoverpa armigera, however there is a common opinion among farmers that S. litura is an emerging problem in Bt cotton. There is an urgent need to screen for more toxic holotype and/or hybrid Cry proteins against S. litura to minimise the use of chemical insecticides in Bt cotton, the main objective of transgenic cotton technology. In laboratory screening experiments G27, the EEC hybrid toxin producing strain, was more toxic than other holotypes (1Ca and 1Fa) and hybrids (AbAbC and AcAcC) tested.