Association of Bactericera cockerelli (Hemiptera: Triozidae) with the perennial weed Physalis longifolia (Solanales: Solanaceae) in the potato-growing regions of western Idaho

Authors: REYES CORRAL, CESAR - Washington State University; Cooper, William - Rodney; Horton, David; MILICZKY, EUGENE - US Department Of Agriculture (USDA); RIEBE, JENNIFER - Jfr Crop Care; WATERS, TIMOTHY - Washington State University; WILDUNG, MARK - Washington State University; KARASEV, ALEXANDER - University Of Idaho

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2021
Publication Date: 8/19/2021
Citation: Reyes Corral, C., Cooper, W.R., Horton, D.R., Miliczky, E., Riebe, J., Waters, T., Wildung, M., Karasev, A. 2021. Association of Bactericera cockerelli (Hemiptera: Triozidae) with the perennial weed Physalis longifolia (Solanales: Solanaceae) in the potato-growing regions of western Idaho. Environmental Entomology. 50(6):1416-1424. https://doi.org/10.1093/ee/nvab076.
DOI: https://doi.org/10.1093/ee/nvab076

Interpretive Summary: Management of the potato zebra chip pathogen and its vector, potato psyllid, is challenging in part because we do not yet know the non-crop source of infective psyllids arriving in potato fields in the Pacific Northwest. Recent research showed that longleaf groundcherry is a very good host for potato psyllid and is also susceptible to the zebra chip pathogen, but this weed has largely been overlooked as a source of infective psyllids in recent field surveys. Researchers at the USDA-ARS laboratory in Wapato, WA in collaboration with researchers from the University of Idaho and Washington State University found that longleaf groundcherry is abundant in the potato growing regions of western Idaho and is often infested with potato psyllids. These findings indicate that longleaf groundcherry should be considered a risk as a source of potato psyllids in potato fields of western Idaho. This weed was difficult to find in the Columbia Basin of Washington, and is not thought to contribute to the spread of zebra chip disease in that region. The realization that longleaf groundcherry is abundant in certain potato growing regions could lead to the development of weed management guidelines that reduce potato psyllid movement from longleaf groundcherry to potato

Technical Abstract: The potato psyllid, Bactericera cockerelli (Šulc), is a major pest of potato (Solanales: Solanaceae) as a vector of “Candidatus Liberibacter solanacearum” (Lso). Bactericera cockerelli colonizes potato from non-crop host plants, yet we do not yet know which non-crop species are the primary sources of Lso-infected psyllids. The perennial weed, Physalis longifolia Nutt., is a high-quality host for B. cockerelli and Lso under laboratory conditions but has been overlooked in recent field studies as a source of Lso-infected psyllids. Our current study had four objectives: 1) determine whether P. longifolia is abundant in potato growing regions of Washington and Idaho, 2) determine whether wild stands of P. longifolia harbor B. cockerelli and Lso, 3) identify the psyllid haplotypes occurring on P. longifolia, and 4) use gut content analysis to infer which plant species the psyllids had previously fed upon prior to their capture from P. longifolia. Online herbaria and field searches revealed that P. longifolia is abundant in western Idaho and is present at low densities in the Columbia Basin of Washington. Over 200 psyllids were collected from P. longifolia stands in 2018 and 2019, confirming that B. cockerelli colonizes wild stands of this plant. Gut content analysis indicated that a proportion of B. cockerelli collected from P. longifolia had arrived there from potato. Confirmation that P. longifolia is abundant in certain potato growing regions of the Pacific Northwest, and that B. cockerelli readily uses this plant, could improve models to predict the risk of future psyllid and Lso outbreaks