Efficacy of Bacillus thuringiensis var.galleriae Berliner and selected insecticides on cotton bollworm, Earias vitella

Cotton, an important cash crop of tropical world, is attacked by many insects. Earias vitella is a major pest in winter crop.Bio-efficacy of B.t, var galleriae as Spicturin®, was evaluated in comparison with insecticides. Two field experimentswere conducted winter and summer seasons with the cotton cultivar LRA- 5166 to assess the efficacy of B.t. on Earias spp. in combination with the insecticides like endosulfan (0.035 %), quinalphos (0.025%), fenvalerate (0.01%) and diflubenzuron (0.075%),endosulfan (0.035%) in combination with B.t.g. @ 3 l/ha was found to be the best in reducingthe boll damage.The damage to the larva tissues is illustrated with thin sections of diseased larva after fixing in blackwax, microtomy sectioning and light microscopy. Cracks in gut lining, damage to gut lumen, epidermis and epithelialcells, basement membrane, musculosa , peritrophic membrane were observed and support the successful pathogenesisand mortality of treated larvae. Keywords: Cotton, boll worm, Earias, Bacillus, squares, pathogenei