Study On Combining Chlorpyrifos With Emamectin Benzoate And Application In Controlling Chilo Suppressalis And Cnaphalocrocis Medinalis

Chilo suppressalis (Walker) and Cnaphalocrocis medinalis (Guenee) which were serious pests of rice in China often outbreak in large areas. They resulted in serious damage of rice production. So, it is very important to find out an effective insecticide for sustainable insect control. In this paper, we combined chlorpyrifos with emamectin benzoate, then got the best proportion of each ingredient, and made the mixture into praeparatum, in order to control the pests:Chilo suppressalis (Walker) and Cnaphalocrocis medinalis (Guenee). The results were as follows:The toxicity in the lab to the larvae of Chilo suppressalis (Walker) was tested with paddy shoots-dipping. By dealing with2d, the LC50of chlorpyrifos was8.8260mg/L, and the LC50of emamectin benzoate was0.0471mg/L. By dealing with4d, the LC50of chlorpyrifos was2.9226mg/L, and the LC50of emamectin benzoate was0.0122mg/L.The best ingredient percentage was screened with CTC toxicity test.The results showed that when the ingredient percentage of chlorpyrifos and emamectin benzoate was57.82:1, the synergistic effect was the most obvious, and the co-toxicity coefficient was346.84.The field control of Chilo suppressalis (Walker) was carried out with the formulation of20%chlorpyrifos-emamectin benzoate EC,20%chlorpyrifos-emamectin benzoate EW, and the antitheses pesticide of200g/L chlorantraniliprole. The results showed that when the dosage was150mL/667m2, the control efficiency of20%chlorpyrifos-emamectin benzoate EC was87.05%, and the control efficiency of20%chlorpyrifos-emamectin benzoate EW was87.71%, which have no obvious difference with the controlling efficiency of200g/L chlorantraniliprole. The chlorpyrifos-emamectin benzoate EW controls Chilo suppressalis (Walker) better than the EC.The field control of Cnaphalocrocis medinalis (Guenee) was carried out with the formulation of20%chlorpyrifos-emamectin benzoate EW and the antitheses pesticide of200g/L chlorantraniliprole.The results showed when the dosage of20%chlorpyrifos-emamectin benzoate EW was100mL/667m2、150mL/667m2 180mL/667m2, the control efficiency was67.00%、73.66%、94.77%, and the leaf-protection efficiency was81.04%、87.65%、91.59%. With180mL/667m2, the20%chlorpyrifos-emamectin benzoate EW could control Cnaphalocrocis medinalis (Guenee) better, without harm to rice, and it had no obvious difference with200g/L chlorantraniliprole.In a word, the dosages of20%chlorpyrifos-emamectin benzoate EW for field controlling Chilo suppressalis (Walker) and Cnaphalocrocis medinalis (Guenee) are150mL/667m2,180mL/667m2separately.