A Novel Chemical -Microbial Hybrid Pesticide In The Management Of S.Oryzae L.

Abstract

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 10⁷ conidia/ml required 6 days to cause 10 percent mortality whereas 4 x 10⁷ 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 10⁷ conidia/ml  with 7.50 µg/dl   acetamiprid killed 100 percent of the S. oryzae in 96 h and at 2 x 10⁷ 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.