Determination of an effective dose of Beauveria bassiana against Thrips tabaci infesting onion

Onion (Allium cepa L.) is one of the most important vegetable crops, among the various bulbous vegetables. There were many insect pest attack on the onion crop among them management of thrips was quite difficult. Management of thrips is problematic due to their minute size, hidden in crevices of flowers and leaf sheaths, and high reproductive capacity leads quickly to great numbers, infesting individual plants. Due to that the experiment was carried out to determine the effective dose of the Beauveria bassiana against Thrips tabaci infesting onion. Results revealed that The B. bassiana at each five doses resulted superior in case of thrips over check. The B. bassiana 1.15% WP @7 g/litre caused the highest mortality of 92.50%and it was at par with B. bassiana 1.15% WP @6 g/litre and B. bassiana 1.15% WP @5 g/litre, which both caused 90.00% mortality. The remaining lower doses of4 and 3 g/litre expressed inferior results. Considering the efficacy along with cost of effective doses, the B. bassiana 1.15% WP @5 g/litre was found the most effective dose against T. tabaci.