【目的】 草地贪夜蛾Spodoptera frugiperda (J. E. Smith)是一种迁飞性的农业重大害虫，2019年入侵我国并暴发成灾。2020年2月调查发现在福建省南部地区（长泰和漳平县）存在草地贪夜蛾越冬种群，而厘清其生物型情况，有助于认识其种群遗传特征与变化趋势，为草地贪夜蛾下一步的治理工作奠定基础。【方法】 采用分子标记方法，对采自玉米田的35个草地贪夜蛾越冬样本分别进行COI和Tpi基因片段的扩增、测序和比对分析，明确福建越冬种群的生物型和遗传特征。【结果】 COI基因序列聚类分析显示福建草地贪夜蛾越冬种群全部为水稻型（与实际寄主玉米不符）；而Tpi基因10个关键位点的序列分析表明为玉米型（与实际寄主一致）。【结论】 福建草地贪夜蛾越冬群体是一个杂合群体，来源并非单一的水稻型或玉米型。入侵后有进一步进行水稻型分化新风险，对福建及周边省份水稻生产造成威胁。

[Objectives]  The fall armyworm (Spodoptera frugiperda J. E. Smith) is a major, migratory, agricultural pest that invaded China in 2019. A field survey in February 2020 found an overwintering population of S. frugiperda in the southern part of Fujian Province (Changtai and Zhangping counties). Clarifying the biotype of this population will further understanding of its genetic characteristics and population trends, and provide a foundation for developing management methods. [Methods]  Using molecular markers, DNA from 35 S. frugiperda overwintering in corn fields was amplified, sequenced and compared to compare their COI and Tpi gene fragments and biotypes, thereby clarifying the characteristics of the overwintering population in Fujian. [Results]  Cluster analysis of the COI gene sequence indicates that, despite being collected on maize, all overwintering specimens were of the Rice-strain. However, sequence comparison of the Tpi gene at several key positions indicated that this was of the Maize-type. [Conclusion]  The results indicate that the overwintering population of S. frugiperda in Fujian is heterozygous, with genes from both the Rice and Maize biotypes. There may be a risk of differentiation of the Rice-type in Fujian, posing a threat to rice production in this and surrounding provinces.