Toxicity of Imidacloprid 17.8%SL and Triflumezopyrim 10%SC to Rice Brown Planthopper Nilaparvata lugens

The rice brown planthopper Nilaparvata lugens (Stål.) is a threat to rice growers and it has developed resistance to many insecticides. Hence, newer molecules like triflumezopyrim 10%SC are available. Its toxicity has been investigated in this study, with four populations from Tamil Nadu along with imidacloprid 17.8%SL using rice seedling dip method. Lower LC₅₀ values of 0.538 ppm and 0.280 ppm were observed with the susceptible populations against imidacloprid 17.8%SL and triflumezopyrim 10%SC, respectively. LC₅₀ values were in range of 0.280-0.848 ppm for triflumezopyrim 10%SC indicating its superior toxicity. Nagapattinam population exhibited moderate resistance (15.36 folds) to imidacloprid 17.8%SL and low resistance (3.02 folds) to triflumezopyrim 10%SC.