Abstract: Spodoptera exigua is an important pest of vegetables.It occurs 6 generations a year in south of Zhejiang Province.They occur from the last ten days of April, and seriously damage the various vegetables during May to December, with the peak period from July to September.Spodoptera exigua can overwinter in the form of pupa within green house.Development duration of Spodoptera exigua is shortened with the increase of temperature within the range from 22.3℃to 27.9℃at natural condition.