Comparison of the susceptibilities of Nilaparvata lugens and Sogatella furcifera from three areas to ten insecticides

The susceptibilities of Nilaparvata lugens and Sogatella furcifera from 3 areas (Guilin,Anqing and Dongtai,China) to 10 insecticides were determined in 2000 and 2001.The results revealed that the populations did not show significant difference in the susceptibility among years or areas,but the difference was significant among insecticides both planthoppers.The highest sensitivity was found in both planthoppers to imidacloprid and ethofenprox. But imidacloprid showed some variation in sensitivity among individuals.If the two insecticides are rationally combined or rotated in use,the chronical use of one insecticide in the control of planthoppers can be avoided,and the insecticide resistance development can be delayed and the longevities of insecticides can be prolonged.