Occurence of Spodoptera frugiperda(J. E. Smith) and adaptability of its larvae to different environments in Southwest Guizhou Autonomous Prefecture, Guizhou Province

【Objective】In order to provide scientific reference for the forecast and integrated control of Spodoptera frugiperda(J. E. Smith) in Southwest Guizhou Autonomous Prefecture by investigating the occurrence and overwintering of S. frugiperda, and test the adaptability of overwintering larvae to different temperature environments.【Method】Cities or counties with high average annual temperature in Southwest Guizhou Autonomous Prefecture were selected as the survey sites, including Wangmo, Xingren, Xingyi, Anlong, Ceheng and Zhenfeng. Searchlight-trap, forecast lamp, sex pheromone trap and field investigation were used to survey the overwintering host and insect stage of S. frugiperda in the winter of 2019 and spring of 2020, and insect number and the mount of insect per 100 plants were counted. The survival rate and pupation rate of S. frugiperda larvae which collected from field were investigated by raising them in indoor, outdoor and artificial climate chest in Wangmo.【Result】In the winter of 2019, only the 3^rd-6^th instars were found on regenerated corn in Sanglang, Wangmo, and the number of larvae were 34.67 per 100 plants. In the spring of 2020, the 1^st-3^rd instars were first found in Sanglang, Wangmo, the host was corn seedling and the highest number of larvae was 28.00 per 100 plants. The 1^st instar larvae were found in Mamaya, Xingren, and the number of larvae per 100 plants reached 30.00. During the field investigation, only one pupa was found in the soil and no adults and eggs. In addition, sex pheromone trap and searchlight-trap first captured the adults of S. frugiperda in Wangmo on January 13, 2020 and March 18, 2020 respectively. Later S. frugiperda were also found in Xingyi, Xingren and Anlong, but the forecast lamp did not capture in anytime. The survival rate of S. frugiperda was indoor > outside > artificial climate chest within two weeks of feeding. The pupation rate was the highest indoors and was the lowest outdoors in the third week.【Conclusion】The results indicate that S. frugiperda can reproduce annually in Southwest Guizhou Autonomous Prefecture, but insect source base number is small in winter, which is unable to become the main insect source of outbreak next year. Moreover, the overwintering larvae of S. frugiperda are more adapted to the cold environment, but not to the mutant warm or the lower temperature.