Management of Sucking Insect Pests of Bt cotton by Buprofezin 70% DF

Development of resistance in leafhopper and other sucking pests in Bt cotton has necessitated the use of newer molecules to manage them. Towards this end two field experiments were conducted during kharif of 2011 and 2012 at Main Agricultural Research Station Raichur to test the bioefficacy of buprofezin 70% DF against sucking pests of Bt cotton and its safety to natural enemies. Buprofezin 70% DF @300g a.i. ha⁻¹ recorded significantly low leafhopper population of 0.32 per leaf at seven days after spraying. This was followed by its next lower dosage of 250g a.i. ha⁻¹. The molecule also brought about significant reduction of whiteflies and mealybugs. It did not exhibit any phytotoxicity on Bt cotton and was safe to the natural enemies viz. spiders and coccinellids. Buprofezin 70% DF @300 g a.i. ha⁻¹ recorded the highest seed cotton yield of 1986.66 kg ha⁻¹ and this was on par with its next lower dosage of 250 g a.i ha⁻¹ (1976.66 kg ha⁻¹), both being significantly superior to the check chemicals imidacloprid and acephate. Therefore its use at 250 g a.i. ha⁻¹ is recommended against cotton sucking pests like leafhopper, whiteflies and mealybugs.