Field Efficacy Experiment of 50% Fipronil·trichlorfon EC against Rice Hopper

[Objective] The study aimed to reveal the optimal dosage of 50% fipronil·trichlorfon EC against rice planthopper.[Method] In order to study the control effect of various treatments against rice planthopper,the 450,600,750 and 900 g/hm2 of 50% fipronil·trichlorfon EC were designed as treatments,meanwhile 37.5 g/hm2of 50 ?g/L fipronil SC and water were regarded as normal control and blank control,respectively.[Result] The results of field experiment showed that there were no obvious phytotoxicity and no obvious harmful effects on rice and natural enemies in all treatments,respectively;750 g/hm2 was the optimal dosage of 50% fipronil·trichlorfon EC against rice planthopper.[Conclusion] 50% fipronil·trichlorfon EC was a high efficacy,low toxicity compound pesticide that could be generalized in production.