Source tracing of (Anthonomus grandis) captured in areas of the USA where the species had previously been eradicated

Authors: RASZICK, TYLER - Texas A&M University; Perkin, Lindsey; SHIRLEY, XANTHE - Animal And Plant Health Inspection Service (APHIS); RUIZ-ARCE, RAUL - Animal And Plant Health Inspection Service (APHIS); KRAMER, ZOEY - Texas A&M University; Suh, Charles; SWORD, GREG - Texas A&M University

Submitted to: Journal of Pest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2023
Publication Date: 8/1/2023
Citation: Raszick, Tyler J., Perkin, Lindsey C., Shirley, Xanthe A., Ruiz-Arce, Raul, Kramer, Zoey A., Suh, Charles P.-C., Sword, Gregory A. 2023. Source tracing of Anthonomus grandis captured in areas of the USA where the species had previously been eradicated. Journal of Pest Science. https://doi.org/10.1007/s10340-023-01656-y.
DOI: https://doi.org/10.1007/s10340-023-01656-y

Interpretive Summary: Although the boll weevil has been eradicated from all cotton production areas in the U.S., with the exception of the southernmost production area of Texas along the Mexico border, eradication programs continue to operate pheromone traps to detect re-infestations. In 2015 and 2017, weevils were captured in a previously eradicated area near Uvalde, Texas, and in Hidalgo Co., New Mexico, respectively. However, the sources of the re-infestations were unknown. We obtained weevils from these two areas and based on our previous genomic work, we were able to identify the likely geographical origin of weevils contributing to these re-infestations. The work also confirmed that the weevils captured in Hidalgo Co. were thurberia weevils, which are difficult to visually distinguish from boll weevils. The ability to accurately distinguish weevil species and determine the geographical origin of re-infestations is critical to eradication programs to help develop policies and regulations to prevent future re-infestations and to reduce unnecessary mitigation costs.

Technical Abstract: The boll weevil, Anthonomus grandis (Coleoptera: Curculionidae), is an important pest of commercial cotton in the western hemisphere. In the United States, an eradication program has been successful, but re-infestations of eradicated or functionally eradicated zones from unmanaged source populations remain a threat to the industry. In 2015 and 2017, boll weevils were captured in pheromone-baited cone traps used by the eradication program for monitoring and early detection of new infestations. In 2015, weevils were trapped in the functionally eradicated Winter Garden growing zone in Texas. Weevils established in the area and triggered a multi-year, multi-million-dollar mitigation effort. In 2017, weevils were trapped in Hidalgo County, New Mexico. Here, weevils did not establish, but the source of the weevils was unknown. In this study, we obtained specimens from both the Winter Garden and Hidalgo Co., NM captures and used double digest restriction site-associated DNA sequencing to obtain SNP information in homology with a previously published boll weevil population genetic investigation. We then used a variety of analyses to compare the outbreak populations to the known populations of boll weevil and assign them to a likely source. We also compared the accuracy of the SNP genotyping to diagnostic methods currently used by the United States Department of Agriculture for determining the sources of boll weevils captured in traps.