Abstract: In this paper, the effect of temperature, ultraviolet radiation and tea dew on the virulence of nuclear polyhedrosis virus from tea geometrid is investigated. Results show that it is suitable for the virus to infect the host larvae of every instar at 18—26℃. The mortality of the larvae fed with virus at the beginning of every instar all reached 100%. But at 30 or 34℃, except the mortality of the larvae fed with NPVat the beginning of the first instar being100%, the mortality, pupation and emergence rate are significantly decreased or increased. When the larvae fed with virus at or after the beginning of the 3rd instar, more than74% larvae pupated and more than89% pupae emerged. The NPVin vitro is distinctly inactivited as exposured to 45℃ for two or more days. The virus in vitro is not inactivited as exposured to ultraviolet radiation for 2—8 minutes and significantly inactivited as exposured for 16 or more minutes. In addition, the effect of UVradiation on the virulence of EoNPVis related to the temperature and the concentration of the virus. Tea dew has a pHof 6.43—6.92 and can't result in an obvious loss in viral activity of the NPVin vitro.

Key words: EoNPV, Virulence, Temperature, Ultraviolet radiation, Tea dew