The repellent activities, including host deterrence and anti-oviposion, of pongam oil against the adults of the common greenhouse whitefly Trialeurodes vaporariorum Westwood in greenhouses were tested. Chrysanthemum plants treated with different concentrations (0.5%-2.0%) of water-suspended pongam oil showed relatively longlasting host deterrent and anti-oviposition effects on the adults of greenhouse whitefly. Although the repellent effect declined in time and concentration, strong effects on the reduction of oviposition were found, which lasts, dependent on concentration at least 12 days after application.