Sublethal effects of abamectin on the development, fecundity, and wing morphs of the brown planthopper Nilaparvata lugens

The brown planthopper Nilaparvata lugens negatively affects rice yield by sucking nutrients from the rice stem and spreading viruses. In this study, the effects of sublethal concentrations of abamectin on development, fecundity, and wing morphs of N. lugens were investigated. Treatment with sublethal concentrations of abamectin showed no significant effects on the developmental period of F-0 nymphs. Although LC10 and LC25 treatments resulted in 10% and 25% mortality, the LC25 treatment significantly prolonged the lifespan of macropterous and brachypterous females. Abamectin-treated brachypterous females showed significantly lower fecundity than control females. Furthermore, abamectin treatment showed no significant effects on the developmental period of F-1 nymphs. However, LC25 treatment significantly inhibited the fecundity of brachypterous F-1 females and significantly reduced the proportion of macropterous F-1 females and brachypterous F-1 males. LC25 treatment showed no significant effects on the fecundity of macropterous F-1 females. Considering the proportion of macropterous and brachypterous F-1 females, the relative fitness of the macropterous F-1 nymphs in the control, LC10, and LC25 treatment groups was 1, 1.02, and 0.84, respectively, and that of brachypterous F-1 nymphs was 1, 0.79, and 0.93, respectively. Sublethal concentrations of abamectin inhibited N. lugens emergence. The present findings indicate the potential of abamectin for N. lugens field control.