Biological Activity and Control Effect of Nilaparvata lugens on the Pymetrozine and Isoprocarb and Mixed Pesticides

The result of the biological activity showed that the LC 50 and co-toxicity coefficient(CTC)of the mixture of pymetrozine and isoprocarb at the ratio of 1:2,which had excellent effect against the 3 th larval stage of Nilaparvata lugens,were 11.01 mg/L and 166.65,respectively.The mixture indicated addition effect,obviously.The results of field trials of pymetrozine and isoprocarb 30%WP which content pymetrozine and isoprocarb at the ratio of 1:2,showed that the mixture reagent had favorable quick-acting and persistent effects.The effect of pymetrozine and isoprocarb 30%WP at the dose of 450-600 g/ha was 90.83-94.94%after 3 days,and was still 87.60-89.32%after 21 days,which were all much better than pymetrozine or isoprocarb.So pymetrozine and isoprocarb 30%WP at the dose of 450 g/ha is recommended for controlling Nilaparvata lugens.