Fall armyworm (Spodoptera frugiperda) is a noctuid moth from the Americas with a broad host range that threatens a range of important crops. It consists of two morphologically indistinguishable strains (‘corn’ and ‘rice’) that have different host plant preferences. It was detected for the first time in Australia in 2020 following its rapid dispersal through Africa and Asia. Species identification of S. frugiperda in 48 specimens from seven locations in the Northern Territory was confirmed by DNA barcoding and morphological assessment. The majority of specimens possessed the mitochondrial haplotype associated with the ‘rice-strain’, whereas two specimens had a haplotype identified as the ‘corn-strain’. The two mitochondrial haplotypes observed in our study are identical to the most common haplotypes previously observed in Africa. Analysis of a nuclear gene identified all specimens as ‘corn-strain’. The agreement of both mitochondrial and nuclear markers as ‘corn-strain’ haplotypes occurred in two samples only, suggesting discrepancies between the mitochondrial and nuclear markers analysed. As fall armyworm spreads to other locations in Australia, further monitoring and genetic characterization of populations is recommended to investigate strain, genetic diversity and population structure. Monitoring of populations in association with host plant preferences will provide valuable information on host plant preferences and strain characterisation.

秋夜蛾（Spodoptera frugiperda）是美洲的一种夜蛾，寄主范围广泛，威胁着许多重要农作物。它由两个形态上无法区分的菌株（“玉米”和“大米”）组成，它们具有不同的寄主植物偏好。在迅速传播到非洲和亚洲之后，该病于2020年在澳大利亚首次被发现。S的种类鉴定。弗鲁吉佩达DNA条形码和形态学评估证实了北领地7个地点的48个标本中的4个标本。大部分标本具有与“水稻株”相关的线粒体单倍型，而两个标本具有被鉴定为“玉米株”的单倍型。在我们的研究中观察到的两种线粒体单倍型与以前在非洲观察到的最常见的单倍型相同。核基因分析确定所有标本为“玉米株”。仅在两个样品中，线粒体和核标记物均符合“玉米株”单倍型，这表明分析的线粒体和核标记物之间存在差异。随着秋夜蛾传播到澳大利亚的其他地区，建议进一步监测种群的遗传特性以调查菌株，遗传多样性和种群结构。与宿主植物偏好相关的种群监测将提供有关宿主植物偏好和菌株鉴定的有价值的信息。