Native Bt strains efficacy against cotton aphid Aphis gossypii Glover

Abstract

The microbial pesticide market is dominated by Bacillus thuringiensis (Bt) but still a significant number of insect pests that cause immense losses on crop production are not sensitive to the commercially available Bt toxins in spite of the variability of Cry proteins. In the present study three native Bt strains (VKK-ENT1, VKK-ENT2, VKK-ENT3) were isolated from the soil and evaluated their efficacy against the cotton aphids in three different forms of feeding assays i.e. pre-solubilized, solubilized and trypsinized form. In pre-solubilized form the mortality ranged from 23.33 to 46.66%. In solubilized (30 to 53.30%) and trypsinized form (13.33 to 36.66%) mortality was found. Further studies are required on biochemical, physiological and molecular characterization of these Bt isolates.