Inhibition of rice virus transmission by esfenvalerate and its mechanisms

Synthetic pyrethroid esfenvalerate, reduced the incidence of the rice stripe virus disease transmitted by smaller brown planthoppers, Laodelphax striatellus, in the greenhouse. To make clear the mechanisms preventing virus infection, the effects of esfenvalerate on vectors were investigated. This compound showed a high repellent activity against smaller brown planthopper which is a stripe disease vector, and green rice leafhopper, Nephotettix virescence, which is a tungro vector. Electronic measurement of insect feeding behaviour revealed that 1 ppm of esfenvalerate inhibited the ingestion and salivation of both species. These results suggested that insecticide lethality, repellency and/or activity inhibiting ingestion and salivation behaviour contributes to prevention of virus infection by planthoppers and leafhoppers.