BIO-EFFICACY OF NEEM OIL AND DELTAMETHRIN AGAINST SPOTTED BOLL WORM Earias vittella (Fab.) (Noctuidae: Lepidoptera) ON COTTON (MCU 5)

A study was carried out to test the bio-efficacy of neem oil at 0.10 to 0.50 per cent concentrations alone and in combination with the pyrethroid deltamethrin (0.09% ) on cotton CMCN 5) under field condition during winter 1986-1987. Deltamethrin (0.09%) was the most effiective treatment in minimising shoot, square, bolls, kapas and loculi infestation due to E. vittella. The next best treatments were neem oil at 0.5% alone and combinations of neem oll 0.30, 0.40 and 0.50% with deltamethrin 0.09%. Deltamethrin 0.09% spray recorded the maximum yield. Deltamethrin in com- bination with neem oil recorded higher yield than neem oil alone. Yield loss was minimum in detalmethrin 0.09% alone. Deltamethrin 0.09% alone can be used for effective control of bollworms and realising appreciably high yield of kapas. Addition of neem oil and deltamethrin spray fluid has not conferred any additional benefits.