10.22376/ijpbs.2019.10.1.p1-12 Volume 2 Issue 4 2011 (October - December) Mortality of rice weevil, lessThan i greaterThan Sitophilus oryzae lessThan /i greaterThan (L.) caused by lessThan i greaterThan Metarhizium anisopliae lessThan /i greaterThan (Metschnikoff) Sorokin alone and in combination with a neonicotinoid insecticide, acetamiprid was evaluated in laboratory bioassays. Spray application of lessThan i greaterThan M. anisopliae lessThan /i greaterThan alone at a spore concentration of 6 x 10 lessThan sup greaterThan 7 lessThan /sup greaterThan conidia/ml required 6 days to cause 10 percent mortality whereas 4 x 10 lessThan sup greaterThan 7 lessThan /sup greaterThan 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, lessThan i greaterThan M. anisopliae lessThan /i greaterThan killed lessThan i greaterThan S.oryzae lessThan /i greaterThan significantly faster than without acetamiprid. lessThan i greaterThan M. anisopliae lessThan /i greaterThan at a spore concentration of 3 x 10 lessThan sup greaterThan 7 lessThan /sup greaterThan conidia/ml with 7.50 µg/dl acetamiprid killed 100 percent of the lessThan i greaterThan S. oryzae lessThan /i greaterThan in 96 h and at 2 x 10 lessThan sup greaterThan 7 lessThan /sup greaterThan conidia/ml with 5.00 µg/dl acetamiprid killed 100 percent in 120 h. lessThan i greaterThan S. oryzae lessThan /i greaterThan , lessThan i greaterThan M. anisopliae - lessThan /i greaterThan  acetomiprid combination resulted in higher mortality. Statistical analysis demonstrated synergistic interaction between these two insecticides. S.M. Vijila , S. Sam Manohar Das And R. Raja Jeya Sekar Metarhizium anisopliae, acetamiprid, Sitopilus oryzae, synergism, hybrid pesticide 116-121