Spinetoram resistance in Spodoptera frugiperda: Molecular mechanisms, diagnostic tools, and management implications

Spodoptera frugiperda (fall armyworm) has emerged as a major global pest of maize and other crops. Spinetoram, a widely used spinosyn insecticide, has played a central role in its management; however, increasing reports of resistance threaten the long-term sustainability of this compound. This review synthesizes current knowledge on spinetoram resistance in S. frugiperda, encompassing field reports, underlying molecular mechanisms, and emerging diagnostic approaches. Clear evidence of resistance has been reported from Brazil, whereas studies from China and Pakistan indicate emerging resistance. Molecular and transcriptomic analyses consistently associate cytochrome P450 monooxygenases, glutathione S-transferases, carboxylesterases, ATP-binding cassette transporters, and cuticular proteins with reduced susceptibility phenotypes. However, their direct contribution to spinetoram resistance remains to be fully resolved. In contrast, functional validation supports a causal role for mutations in the nicotinic acetylcholine receptor α6 subunit. Advances in transcriptomic analyses, qRT-PCR validation, and RNA interference-based diagnostic platforms further strengthen the early detection of resistant populations. Collectively, integrating field surveillance with mechanistic and diagnostic insights provides a useful framework for molecularly informed resistance management, emphasizing the importance of Insecticide Resistance Action Committee-guided insecticide rotation, Bacillus thuringiensis-based integrated pest management, and the development of novel RNA interference-based biocontrol strategies to preserve spinetoram efficacy and ensure sustainable crop protection. © 2026 Society of Chemical Industry.