Studies on Resistance Development and Detoxification Enzyme of Rice Weevil, Sitophilus oryzae to Insecticides Neethu P, Varghese Thania Sara1,*, Anitha N, George Thomas1, Kumar T Santhosh Department of Agricultural Entomology, College of Agriculture, Vellayani, Kerala Agricultural University, Thrissur, Kerala, India 1Pesticide Residue Research and Analytical Laboratory, College of Agriculture, Vellayani, Kerala Agricultural University, Thrissur, Kerala, India *Correspondence : thania.sv@kau.in
Online Published on 14 December, 2023. Abstract Insecticide resistance is a challenging factor for the management of rice weevil, Sitophilus oryzae. The susceptibility of five insecticides with different modes of action was tested against S. oryzae and the biochemical basis of resistance was also evaluated. The film method of bioassay was used to evaluate the susceptibility of malathion, deltamethrin, fipronil, indoxacarb and chlorantraniliprole against field and laboratory populations of S. oryzae. Among the insecticides tested, malathion (RR 14.9) and deltamethrin (RR 9.0) showed significantly higher resistance in the field population of S. oryzae when compared to the lab-reared population. The resistant ratios of fipronil, indoxacarb, and chlorantraniliprole were negligible. When compared to malathion, fipronil and indoxacarb were 619.8 and 40.13-fold toxic to S. oryzae and chlorantraniliprole was the least toxic. The activities of detoxifying enzymes like cytochrome P450 (0.74 p mol min-1 mg-1 protein), carboxylesterases (0.65 µ mol min-1 mg-1 protein) and glutathione S-transferase (0.41 µ mol min-1 mg-1 protein) were significantly higher in the field population compared to lab-reared insects. Top Keywords Resistance, Sitophilus oryzae, Insecticide, Enzymes, Deltamethrin, Malathion. Top |