Analysis of strain distribution, migratory potential, and invasion history of fall armyworm populations in northern Sub-Saharan Africa

Authors: Nagoshi, Rodney; GOERGEN, GEORG - INSTITUT NATIONAL DES RECHERCHES AGRICOLES DU BENIN (INRAB); TOUNOU, KODJO - UNIVERSITY OF LOME; AGBOKA, KOMI - UNIVERSITY OF LOME; KOFFI, D - UNIVERSITY OF GHANA; Meagher, Robert - Rob

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2018
Publication Date: 2/27/2018
Citation: Nagoshi, R.N., Goergen, G., Tounou, K.A., Agboka, K., Koffi, D., Meagher Jr, R.L. 2018. Analysis of strain distribution, migratory potential, and invasion history of fall armyworm populations in northern Sub-Saharan Africa. Scientific Reports. 8:3710. https://doi.org/10.1038/s41598-018-2-21954-1.
DOI: https://doi.org/10.1038/s41598-018-21954-1

Interpretive Summary: The fall armyworm is the primary pest of corn production in South America and in portions of the southeastern United States. Severe outbreaks of fall armyworm have now been reported throughout sub-Saharan Africa, posing a significant threat to African agriculture with the potential for rapid dispersion throughout the hemisphere. Scientists at USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida, with colleagues from the African institutions of the University of Ghana, the Université de Lomé (Togo), and IITA collected and genetically characterized moth specimens from several African nations. The genetic analyses provided important information on the migratory potential, strain behavior, and invasion history of the pest in Africa. The information will be critical for future efforts to monitor, predict, and control the spread of this invasive pest in the Eastern Hemisphere and provide new insights into how invasive moths behave that will be relevant to understanding similar events in the United States.

Technical Abstract: Fall armyworm (Spodoptera frugiperda, J.E. Smith) is a noctuid moth pest endemic throughout the Western Hemisphere that has recently become widespread in Sub-Saharan Africa. There is a strong expectation of significant damage to African maize crop yield and a high likelihood of further dispersal, putting the rest of the Eastern Hemisphere at risk. Specimens from multiple locations in six countries spanning the northern portion of the infested region were analyzed for genetic markers. The similarity of haplotypes between the African collections was consistent with a common origin, but significant differences in the relative frequency of the haplotypes indicated limitations in migration. The mitochondrial marker frequently used to identify two host strains appears to be compromised, making uncertain previous reports that both strains are present in Africa. This more extensive study confirmed initial indications based on Togo populations that Florida and the Greater Antilles are the likely source of at least a subset of the African infestation and further suggest an entry point in western Africa. The origin of a second subgroup is less clear as it was rarely found in the collections and has a haplotype that has not yet been observed in the Western Hemisphere.