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

Authors: HAY-ROE, MIRIAN - University Of Florida; Nagoshi, Rodney; Meagher, Robert - Rob; ARIAS DE LOPEZ, MYRIAM - National Institute For Agricultural Research (INIAP); TRABANINO, ROGELIO - Zamorano, Panamerican School Of Agriculture

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2015
Publication Date: 8/5/2015
Citation: Hay-Roe, M., Nagoshi, R.N., Meagher Jr, R.L., Arias De 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: The migratory pest fall armyworm (Spodoptera frugiperda) attacks corn, cotton, grasses, and rice in North and South America and in the Caribbean, and is the number one pest of sweet corn in south Florida. Once sweet corn plants grow to the tassel stage, fields are sprayed every 2-3 days with insecticides to control fall armyworm populations. One alternative to pesticide sprays, especially early in the season, is to allow natural enemies to reduce numbers of this pest. One natural enemy species that has been released in large numbers in South America is the egg parasite known as Telenomus remus. Although releases of this tiny wasp were made in the mid-1970s and late 1980s, it wasn’t known if the species had been established in Florida. Researchers at the USDA-ARS CMAVE laboratory, in collaboration with a scientist at the University of Florida and scientists from Ecuador and Honduras, collected wasps parasitizing fall armyworm eggs from two north central Florida counties. DNA sequences from the Florida wasps were compared to wasps collected in Ecuador and Honduras and positively identified as T. remus. These exciting results show that this potentially beneficial parasite was probably established from earlier releases and gives current researchers another biological weapon against fall armyworm.

Technical Abstract: Telenomus remus Nixon is a platygastrid egg parasite of the fall armyworm, 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 and again in 1988-1989 to introduce T. remus into the fall armyworm overwintering regions of southern Florida to mitigate infestations by this migratory pest, but in neither case was evidence of long-term establishment found. However, in 2009 and again in 2013, an unidentified Telenomus species was found attacking 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.