LAMP-based rapid detection of pesticide resistance mutations in the <i>ace-1</i> gene of fall armyworm <i>Spodoptera frugiperda</i> (Lepidoptera: Noctuidae)

The fall armyworm (Spodoptera frugiperda), a lepidopteran pest of highly destructive, has developed resistance to organophosphate and carbamate insecticides through target-site mutations, including A201S and F290V in the ace-1 gene encoding acetylcholinesterase (AChE). Developing rapid and reliable methods to detect these mutations is crucial for monitoring resistance and guiding effective management strategies. Although S. frugiperda populations remain sensitive to the tested insecticides, the A201S and F290V mutations were identified in collected field samples. To facilitate detection, a sensitive and field-deployable loop-mediated isothermal amplification (LAMP) assay was developed, targeting these mutations within the ace-1 gene of S. frugiperda. The specificity and sensitivity of the LAMP assay was optimized for rapid detection, with reactions performed at 68 °C for 80 min. Results were visualized through color change and confirmed by gel electrophoresis. Validation using DNA from laboratory and field samples demonstrated complete agreement between the LAMP assay and DNA sequencing, affirming the accuracy and reliability of the method. The developed LAMP assay provides a simple, rapid, and effective tool for detecting the A201S and F290V mutations in the ace-1 gene of S. frugiperda. The assay's simplicity, isothermal operation, and clear visual results make it a valuable tool for resistance monitoring and integrated pest management in agricultural settings.