The insecticide susceptibility of the brown planthopper, Nilaparvata lugens, and white-backed planthopper, Sogatella furcifera, collected from China and Japan

Abstract

We determined the insecticide susceptibility of the brown planthopper (BPH) and white-backed planthopper (WBPH), which were collected from China and Japan in 1997, by topical application. The insecticide susceptibility of BPH was not much different among populations from Nagasaki (Southwest Japan), Hangzhou (Zhejiang, China), and Jinghong (Yunnan, China). The LD50s for BPH were 0.027-0.062 for nitenpyram, 0.083-0.14 for imidacloprid, 0.58-0.88 for silafluofen, and 0.78-1.2μg/g for etofenprox, in contrast to 67-130 for malathion, 51-93 for fenitrothion, and 57-94 μg/g for p, p' -DDT. Thus, the LD₅₀S of chlornicotinyl and the pyrethroids were much smaller than those of the organophosphates and organochloride. The LD₅₀ of monocrotophos was 1/23-1/3 times as large as that of the other organophosphates. The organophosphate and carbamate susceptibilities were not different between BPH populations collected in 1992 and 1997. The insecticide susceptibility of WBPH was not much different among the populations from Nagasaki, Hangzhou and Jinghong. The LD₅₀S for WBPH were 0.047-0.062 for nitenpyram, 0.067-0.18 for imidacloprid, 0.72-1.5 for silafluofen, and 0.89-1.6 μg/g for etofenprox, in contrast to 96-130 for malathion, 100 for fenitrothion, and 22-51μg/g for p, p'-DDT. Thus, the LD₅₀S of chlornicotinyl and the pyrethroids were much smaller than those of the organophosphates and organochloride. The LD₅₀ of monocrotophos was 1/17-1/3 as large as that of the other organophosphates. The LD₅₀S of isoprocarb and propoxur for WBPH populations collected in 1997 were 5 times as large as in 1989.