Crop damage caused by fall armyworm (FAW), Spodoptera frugipera J.E. Smith (1797) (Lepidoptera: Noctuidae), has generated concern among agriculturists globally. In 2019, FAW was first reported in Sri Lanka, where it caused significant losses to corn crops. However, given that the two FAW biotypes – “rice strain” (R-FAW) and “corn strain” (C-FAW) – are morphologically identical, the biotype(s) present in Sri Lanka were unknown. The current study used the mitochondrial cytochrome c oxidase subunit I gene (mt-CO1) of FAW to biotype nine FAW samples collected in Sri Lanka. The resulting molecular phylogeny revealed that both R-FAW and C-FAW biotypes were present among the samples. In addition, we used the temperature-switch polymerase chain reaction (PCR) technique to develop a gel-based molecular marker. Two fragments were successfully amplified by the newly developed marker ABUOP0002, with fragment sizes of 341 bp from R-FAW and 204 bp from C-FAW. This demonstrates that ABUOP0002 can serve as a diagnostic gel-based molecular marker to identify the R-FAW and C-FAW biotypes from samples already identified to species level as S. frugiperda through taxonomical keys and provides a possible alternative to more expensive sequencing-based assays.

秋天的粘虫（FAW），草地贪夜蛾（Spodoptera frugipera JE Smith，1797年）（鳞翅目：夜蛾科）对作物的损害已引起全球农业学家的关注。2019年，一汽首次在斯里兰卡报道，这给玉米作物造成了重大损失。但是，鉴于两种一汽生物型-“稻株”（R-FAW）和“玉米株”（C-FAW）在形态上是相同的，因此在斯里兰卡存在的生物型是未知的。当前的研究使用了线粒体细胞色素C氧化酶亚基I基因（mt- CO1一汽）将斯里兰卡收集的九种一汽样品生物型化。所得的分子系统发育学表明，样品中同时存在R-FAW和C-FAW生物型。此外，我们使用了温度开关聚合酶链反应（PCR）技术来开发基于凝胶的分子标记。新开发的标记ABUOP0002成功扩增了两个片段，R-FAW的片段大小为341 bp，C-FAW的片段大小为204 bp。这表明ABUOP0002可以用作基于凝胶的诊断性分子标记，以通过分类键从已经鉴定到物种水平为S. frugiperda的样品中鉴定R-FAW和C-FAW生物型，并为更昂贵的基于测序的方法提供了可能的替代方法分析。