1993 Volume 28 Issue 3 Pages 339-346
The brown planthopper, Nilaparvata lugens STAL, is known to immigrate annually into Japan from overseas, primarily from mainland China. The susceptibility to insecticides of the brown planthopper in the Ono area, Hyogo Prefecture, was monitored annually for 8 years, from 1980 to 1987, by the micro topical application technique. The susceptibility to 8 insecticides tested fluctuated greatly at levels which indicated some degree of resistance. The brown planthopper collected in 1874 and 1985 showed extremely high LD50 values to both carbamates and organophosphates. Data for other prefectures showed similar fluctuations. The LD50 values for 1984 and 1985 were also high.
