Effect of Neem Oil on Survival of Nilaparvata lugens (Homoptera: Delphacidae) and on Grassy Stunt and Ragged Stunt Virus Transmission

Neem ( Azadirachta indica A. Juss) seed oil was found highly effective in reducing the survival of a planthopper, Nilaparvata lugens (Stal), and in suppressing transmission of grassy stunt and ragged stunt viral diseases of rice. Generally, insect survival and disease transmission decreased with increasing neem oil concentrations. After 3 days of exposure, the insect failed to transmit the viruses to plants sprayed with 50% neem oil, compared with control plants where virus transmission was successful.