Abstract: The study on the nuclear polyhedral virus epidemic of Spodoptera litura under effects of temperature showed that at above 29 ℃,S.litura larvae started to die 2～3 d after virus-inoculation,and reached the peak 4～5 d after the inoculation.The mortality and death velocity of virusinfected host larvae were increased with increasing incubation temperature.No thermo-inhibition temperature for the virus was observed in the test temperature range,while there existed a constant temperature range,i.e.,29～35 ℃,for the highest mortality of infected host larvae.Complementary log-log regression model could well simulate the daily distribution of host larvae mortality,and the cumulative disease death time could be described by Gompertz model.The revised biophysical model could well simulate the relationship between S.litura larvae mortality and temperature,and be applied to virus epidemic forecasting.

Key words: Winter wheat, Booting stage, Waterlogging, Root system, Senescence