Isolation and DNA barcode characterization of a permanent Telenomus (Hymenoptera: Platygastridae) population in Florida that targets fall armyworm (Lepidoptera: Noctuidae)

Authors: Hay-Roe, Mirian; Nagoshi, Rodney; Meagher, Robert - Rob; DE LOPEZ, MYRIAM - Instituto Nacional De Investigação Agrária E Veterinária; TRABANINO, ROGELIO - Honduran Foundation For Agricultural Research (FHIA)

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2015
Publication Date: 9/1/2015
Citation: Hay-Roe, M.M., Nagoshi, R.N., Meagher Jr, R.L., Lopez, M., Trabanino, R. 2015. Isolation and DNA barcode characterization of a permanent Telenomus (Hymenoptera: Platygastridae) population in Florida that targets fall armyworm (Lepidoptera: Noctuidae). Annals of the Entomological Society of America. 108(5):729-735.
DOI: https://doi.org/10.1093/aesa/sav074

Interpretive Summary: Fall armyworm, a major pest of corn and cotton in the Western Hemisphere, annually infests much of the continental USA and Canada. These populations arise from populations that overwinter in the southern regions of Florida and Texas, with the Florida migration the primary source of infestations in those states lying east of the Appalachian Mountain Range as far north as Pennsylvania. The parasitic wasp Telenomus remus (Nixon) is an effective biological control agent for fall armyworm and is frequently used in augmentative releases in Central and South America. There was an attempt 40 years ago to establish this wasp in Florida, but it was not successful. In this paper we demonstrate for the first time the presence of a permanent Telenomus population in the United States that targets fall armyworm. The available genetic evidence suggests that the species is T. remus, which may be a remnant of mass release studies done in the 1970s, or the result of a subsequent unintended introduction. The identified specimens were collected within 500 km of the fall armyworm overwintering regions in southern Florida, suggesting that T. remus might already or soon be established in areas that could mitigate migratory fall armyworm populations. Facilitating the establishment of permanent Telenomus populations at sites where winter corn is grown and augmenting the parasitoid density with appropriately timed mass releases could provide a cost-effective and environmentally benign method of reducing fall armyworm infestations for a large portion of the eastern United States.

Technical Abstract: Telenomus remus (Nixon) is a scelionid egg parasite of the fall armworm, Spodoptera frugiperda (J. E. Smith), with a history of use as an augmentative biological control agent in Central and South America. Efforts were made in 1975-1977 to introduce T. remus into the fall armyworm overwintering regions of southern Florida in order to mitigate infestations by this migratory pest, but no evidence of long-term establishment was found. However, in 2009 and again in 2013, an unidentified Telenomus species was found infecting fall armyworm sentinel egg masses placed on corn plants or pasture grasses in the north-central Florida counties of Levy and Alachua. Taxonomic uncertainties have so far not allowed a conclusive identification of species by morphological keys. DNA barcode comparisons showed a single Florida haplotype in all collections that was identical to that found in a T. remus colony from Ecuador and very similar to a T. remus colony from Honduras. The T. remus barcode sequences were phylogenetically distinct from a second Telenomus species from Ecuador, T. rowani, and from other related sequences obtained from the NCBI GenBank database. This represents the first observation of a permanent Telenomus population in the United States that targets fall armyworm and provides genetic evidence for its identification as T. remus. These findings have positive implications for the use of augmentative biological control methods to mitigate fall armyworm migration from Florida.