|OHLER, BONNIE - Washington State University
|REYES CORRAL, CESAR - Washington State University
|Cooper, William - Rodney
|WATERS, TIM - Washington State University
Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2023
Publication Date: 9/13/2023
Citation: Ohler, B.J., Reyes Corral, C.A., Cooper, W.R., Horton, D.R., Waters, T.D. 2023. Targeted RT-PCR based gut content analysis for potato psyllid predation in laboratory assays. American Journal of Potato Research. https://doi.org/10.1007/s12230-023-09920-8.
Interpretive Summary: Potato psyllid is a key pest of potato as the vector of the pathogen that causes zebra chip disease of potato. Biological control could provide a means to manage potato psyllid without the use of insecticides, but identifying which predators actually feed on potato psyllids is challenging. Researchers at the USDA-ARS laboratory in Wapato, WA and from Washington State University developed a method called gut content anlaysis to identify potato psyllid DNA in the guts of predator insects, spiders, and mites. While confirming the usefullness of this technique, the scientists discovered that whirlygig mites are likely a more important predator of potato psyllid than currently recognized, and deserve further study. Gut content anlaysis will be a useful tool in identifying important predators of potato psyllid in crop and non-crop habitats.
Technical Abstract: RT-PCR was used to test whether DNA from potato psyllid (Bactericera cockerelli) could be detected in generalist predators that had been allowed to feed on the psyllid in laboratory feeding trials. The assay borrowed primers developed in Europe to amplify a region of the ITS2 gene in psyllids for use in identifying psyllid specimens intercepted at border inspection stations or discovered on solanaceous host plants in regions currently free of the pest. We conducted feeding trials with arthropod generalist predators in diverse taxonomic groups (Araneae, Acari, and 2 orders of Insecta). RT-PCR readily detected potato psyllid DNA in predators that had recently fed upon the insect. DNA from a closely related psyllid, Bactericera dorsalis, was not detected, suggesting that our approach is unlikely to lead to false positives. RT-PCR was found to be more sensitive than conventional PCR at detecting very dilute quantities of potato psyllid DNA. Predator taxa differed in how long after a feeding event prey DNA could be detected. Signal retention was longer in spiders and a predatory mite (Anystis) than in predatory true bugs (Hemiptera). We believe this new molecular tool will be of value in identifying potentially important sources of psyllid biological control under field conditions.