In order to study the main biological characteristics of Spodoptera frugipetda,the developmental duration, fecundity, developmental threshold temperature and effective accumulated temperature of different stages were measured on maize seedlings were used as feed under five temperature conditions: 20℃, 25℃, 28℃, 32℃ and 35℃, in laboratory. The results showed that the development duration of S. frugipetda (egg, larvae, pupae and adult) was gradually decreased with the increase of temperature within the range from 20℃ to 35℃, and the generation development duration was 23.0~48.3 d. The developmental threshold temperatures of egg, larvae, pupa, adult and whole generation were 12.70℃, 11.11℃, 11.01℃, 5.65℃ and 9.21℃, respectively. And the effective accumulate temperatures were 39.4 d·℃、201.25 d·℃、134.12 d·℃、171.06 d·℃ and 636.53 d·℃. The optimum temperature for eggs, larvae, pupa developing and adults oviposition was 20~32℃. However, the temperature of 15℃ and 35℃ were not conducive to S.frugiperda growth and development. Base on the tested developmental threshold temperature and effective accumulative temperature, the paper speculated that the generation numbers of S. frugipetdain the middle regions, west, south, southeast, southwest, northeast and northwest were 2.18~8.59, 2.28~10.15, 3.43~12.13, 3.15~8.46, 2.75~9.39, 1.38~ 6.87 and 1.11~6.72 respectively in Yunnan Province. |