Southeastern Asia fall armyworms are closely related to populations in Africa and India, consistent with common origin and recent migration

Authors: Nagoshi, Rodney; HTAIN, NI NI - Department Of Agriculture-Bureau Of Plant Industry; BOUGHTON, DOUGLAS - University Of Michigan; ZHANG, LEI - Chinese Academy Of Agricultural Sciences; XIAO, YUTAO - Chinese Academy Of Agricultural Sciences; NAGOSHI, BENJAMIN - University Of South Florida; MOTA-SANCHEZ, DAVID - University Of Michigan

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2020
Publication Date: 1/29/2020
Citation: Nagoshi, R.N., Htain, N., Boughton, D., Zhang, L., Xiao, Y., Nagoshi, B.Y., Mota-Sanchez, D. 2020. Southeastern Asia fall armyworms are closely related to populations in Africa and India, consistent with common origin and recent migration. Scientific Reports. 10:1421. https://doi.org/10.1038/s41598-020-58249-3.
DOI: https://doi.org/10.1038/s41598-020-58249-3

Interpretive Summary: The fall armyworm is the primary pest of corn production in the Western Hemisphere. Severe outbreaks of fall armyworm have now been reported throughout sub-Saharan Africa India, and southeast Asia posing a significant threat to global agriculture. This makes understanding the migratory behavior of fall armyworm critical to controlling the spread of this pest. Scientists at USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida, with colleagues from Michigan State University, Myanmar, and China collected and genetically characterized moth specimens from southeastern Asia. These studies represent the first genetic description of fall armyworm from Myanmar, which is a likely source population for migration into China and the rest of northern Asia. The fall armyworm from Myanmar, China, India, and Africa were found to be closely related suggesting a common origin for these geographically distant populations and consistent with a single recent incursion into the Eastern Hemisphere. The rapid spread of the pest demonstrate the threat posed by invasive moth pests and the need for extensive monitoring and rapid response mitigation strategies. The genetic studies further indicate that the fall armyworm subpopulation most likely to be a threat to rice and millet, major crops in Asia, is not present in significant numbers in Myanmar and southern China.

Technical Abstract: The discovery of fall armyworm, a native of the Western Hemisphere, in western Africa in 2016 was rapidly followed by detections throughout sub-Saharan Africa, India, and most recently southeastern Asia. This moth pest has a broad host range that threatens such important crops as corn, rice, millet, and sorghum, creating concern for its potential impact on agriculture in the Eastern Hemisphere. Although genetic data suggest populations sampled in Africa and India originate from a recent common source, it is not known whether this is the case for populations in southeastern Asia, nor whether the subgroup with a preference for rice and millet is present in the region. This study found through comparisons of genetic markers that the fall armyworm from Myanmar and southern China are closely related to those from Africa and India, suggesting a common origin for these geographically distant populations and consistent with a single recent introduction into the Eastern Hemisphere followed by rapid dispersion. The molecular similarities include discrepancies between the genetic markers that brings into question whether the subpopulation most likely to be a threat to rice and millet is present in significant numbers in Asia.