Comparative molecular analyses of invasive fall armyworm in Togo reveal strong similarities to populations from the eastern United States and the Greater Antilles

Authors: Nagoshi, Rodney; KOFFI, DJIMA - UNIVERSITY OF GHANA; AGBOKA, KOMI - UNIVERSITY OF BENIN; TOUNOU, KKODJO - UNIVERSITY OF BENIN; BANERJEE, RAHUL - UNIVERSITY OF TENNESSEE; JURAT-FUENTES, JUAN - UNIVERSITY OF TENNESSEE; Meagher, Robert - Rob

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/13/2017
Publication Date: 7/24/2017
Citation: Nagoshi, R.N., Koffi, D., Agboka, K., Tounou, K.A., Banerjee, R., Jurat-Fuentes, J.L., Meagher Jr, R.L. 2017. Comparative molecular analyses of invasive fall armyworm in Togo reveal strong similarities to populations from the eastern United States and the Greater Antilles. PLoS One. 12(7):e0181982. https://doi.org/10.1371/journal.pone.0181982.
DOI: https://doi.org/10.1371/journal.pone.0181982

Interpretive Summary: The fall armyworm is the primary pest of corn production in South America and in portions of the southeastern United States. In 2016, severe outbreaks of fall armyworm were reported in several western and central African countries, representing the first indication of the species establishing itself in the Eastern Hemisphere. The voracious feeding and long-distance flight behaviors exhibited by fall armyworm indicate 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, in collaboration with those at the University of Tennessee and colleagues in the African institutions of the University of Ghana and the Université de Lomé (Togo) collected and genetically characterized moth specimens from several agricultural regions in the African nation of Togo. Genetic analyses confirmed the fall armyworm identification of the specimens, estimated host strain identity, and tested for the presence of the Puerto Rico Bt-resistance allele. The haplotype and marker data were used to extrapolate the most likely Western Hemisphere source locations. This information will be critical for future efforts to monitor, predict, and control the spread of this invasive pest in the Eastern Hemisphere.

Technical Abstract: The fall armyworm (Spodoptera frugiperda, J.E. Smith) is a major and ubiquitous noctuid pest of agricultural in the Western Hemisphere. Infestations have recently been identified in several locations in Africa, indicating its establishment in the Eastern Hemisphere where it poses an immediate and significant economic threat. Genetic methods were used to characterize noctuid specimens infesting multiple cornfields in the African nation of Togo that were tentatively identified as fall armyworm by morphological criteria. Species identification was confirmed by DNA barcoding and the specimens were found to be primarily of the subgroup that preferentially infests corn and sorghum in the Western Hemisphere. The mitochondrial haplotype configuration was most similar to that found in the Caribbean region and the eastern coast of the United States, identifying these populations as the likely originating source of the Togo infestations. A genetic marker associated with a Bacillus thuriengiensis (Bt) toxin resistance trait common in Puerto Rico fall armyworm populations was not found in the Togo collections. These observations demonstrate the usefulness of genetic surveys to characterize fall armyworm populations from Africa.