The wide application and industrialization promotion of transgenic Bt crops not only effectively contained the large-scale outbreak of pests, significantly reduced the application amount of chemical pesticides, but more importantly, alleviated the resulting problems of pesticide residues and environmental pollution. In order to monitor the resistance of S. frugiperda to Bt toxin in Yunnan Province, this study investigated the field populations of fall armyworm in Xundian County, Yunnan Province; diagnostic dose test in the F₂ generation was performed. The research systematically assessed the level of resistance of fall armyworm populations in this area to Bt toxins. Detection results showed that only three single female lines had low-frequency resistance to Cry1Ab (resistance allele frequency of 0.006), but remained highly sensitive to Vip3Aa. This study indicated that the fall armyworm population in Yunnan has not yet developed obvious resistance, providing an important scientific basis for the sustainable promotion of Bt transgenic crops in this area and suggesting the need for long-term resistance monitoring and resistance management strategies.

The fall armyworm, Spodoptera frugiperda, is a globally important invasive agricultural pest and has been listed as a "Category Ⅰ Crop Diseases and Pest" in China. Since its first detection in China in December 2018, the pest has rapidly spread across major agricultural production regions, posing a severe threat to the secure production of key crops such as maize. This review provides a systematic overview of the current research status of S. frugiperda in China, and comprehensively summarizes key advances made over the past seven years, including biotype dynamics, ecological adaptation, invasion mechanisms, resistance evolution, and integrated pest management technologies. In addition, we discuss the existing limitations of current research and outline future research directions, while proposing evidence-based strategies for scientific governance and precision control based on recent advances. This work aims to provide both theoretical foundations and practical guidance for the long-term management and sustainable control of S. frugiperda in China, and also to contribute valuable insights to the study and management of invasive pests worldwide.