Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 3/5/2019
Publication Date: 5/20/2019
Citation: Perkin, L.C., Suh, C.P., Oppert, B.S. 2019. Assessment of DNA integrity from trap-captured boll weevils for use in pending diagnostic tool. National Cotton Council Beltwide Cotton Conference. pp. 157-160.
Interpretive Summary: The boll weevil has been eradicated from over 95% of the cotton acreage in the U.S. but eradication programs continue to operate pheromone traps in eradicated areas to detect potential re-infestations. These traps commonly capture other weevil species that can be mistaken for boll weevils, which in turn, can lead to unnecessary remedial actions and costs. Thus, collaborative efforts with Texas A&M University and USDA-APHIS scientists have been initiated to develop a genetic-based tool to definitively distinguish boll weevils from other weevil species. The viability of this tool relies on the quality and quantity of DNA extracted from weevils exceeding a minimum level. We held boll weevils in pheromone traps for up to 21 days under field conditions and measured the quality and quantity of DNA extracted from these weevils at various time intervals. Our findings indicated that the quality and quantity of DNA extracted from weevils did not change substantially over the three-week period and, more importantly, exceeded the levels required for our diagnostic tool. Therefore, we anticipate our collaborative efforts will eventually provide eradication programs with a tool to accurately and rapidly distinguish weevils captured in pheromone traps, thereby reducing the possibility of improper management decisions.
Technical Abstract: Efforts are underway to develop a PCR-based diagnostic tool that can be used to rapidly and accurately differentiate the boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), from other closely related weevil species (e.g., thurberia weevils), which are commonly captured in boll weevil pheromone traps. Under typical field scenarios, weevils collected from traps may be dead, dismembered, and/or exposed to adverse environmental conditions for up to 21 days. Consequently, the integrity of DNA extracted from these weevil specimens may be too fragmented or yield insufficient amounts for identification via the PCR-based assay. In order to enhance the commercial potential and adoption of this diagnostic tool, we documented the degradation of DNA quantity and integrity in weevils and weevil body parts aged in traps up to a three-week period.