A Novel Chemical -microbial Hybrid Pesticide in the Management of S.oryzae L. S.m. Vijila , S. Sam Manohar Das and R. Raja

Mortality of rice weevil, Sitophilus oryzae (L.) caused by Metarhizium anisopliae (Metschnikoff) Sorokin alone and in combination with a neonicotinoid insecticide, acetamiprid was evaluated in laboratory bioassays. Spray application of M. anisopliae alone at a spore concentration of 6 x 10 conidia/ml required 6 days to cause 10 percent mortality whereas 4 x 10 conidia/ml required 8 days to cause 10 percent mortality. Acetamiprid alone at a concentration of 30.00 μg/dl required 96h to cause 10% mortality and at 20.00 μg/dl required 120 h to cause 20% mortality. In combination with acetamiprid, M. anisopliae killed S.oryzae significantly faster than without acetamiprid. M. anisopliae at a spore concentration of 3 x 10 conidia/ml with 7.50 μg/dl acetamiprid killed 100 percent of the S. oryzae in 96 h and at 2 x 10 conidia/ml with 5.00 μg/dl acetamiprid killed 100 percent in 120 h. S. oryzae, M. anisopliae acetomiprid combination resulted in higher mortality. Statistical analysis demonstrated synergistic interaction between these two insecticides. S.M. VIJILA Department of Zoology, Scott Christian College, Nagercoil