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ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Publications at this Location » Publication #410624
Research Project: Potato Germplasm Development for Improved Sustainability, Disease Resistance, Nutrition, and Quality

Location: Temperate Tree Fruit and Vegetable Research

Title: Improving our understanding of potato mop-top virus in the northwest U.S

Author
item Swisher Grimm, Kylie
item Quick, Rich
item Cimrhakl, Launa
item Feldman, Max
item PAVEK, MARK - Washington State University

Submitted to: Potato Grower
Publication Type: Trade Journal
Publication Acceptance Date: 11/21/2023
Publication Date: 1/1/2024
Citation: Swisher Grimm, K.D., Quick, R.A., Cimrhakl, L.L., Feldman, M.J., Pavek, M. 2024. Improving our understanding of potato mop-top virus in the northwest U.S. Potato Grower. January 2024.

Interpretive Summary:

Technical Abstract: Potato mop-top virus is becoming an increasing global concern due to both yield and quality losses in potato. Tuber symptoms induced by Potato mop-top virus vary by cultivar, but consist of brown, corky, necrotic tissue that appear as flecks, arcs or large blemishes in the tuber flesh. In some cultivars, necrotic arcs or blemishes are found on tuber surfaces. Potato mop-top virus is transmitted to potato by the Spongospora subterranea pathogen which causes powdery scab lesions on tuber surfaces and galling and necrotic lesions on potato roots. There are currently no known chemistries with effective control of the soil-borne vector or virus, rendering this disease complex problematic for potato growers. In addition, no commercial cultivars grown in the United States are known to have immunity to Potato mop-top virus. In theory, resistance can be obtained in two ways: resistance to the virus itself, or resistance to symptom development. For growers focused on domestic markets, lack of tuber symptoms is sufficient at harvest. However, growers focused on international markets require complete immunity to Potato mop-top virus, as diagnostic laboratories in other countries often test for viral detection rather than simply assessing symptom occurrence. Virus detection in asymptomatic tubers (those lacking internal or external tuber symptoms) can therefore lead to lot rejections. Researchers at the USDA Temperate Tree Fruit and Vegetable Research Unit in Prosser, WA, have been working to improve the general understanding of Potato mop-top virus in the northwest U.S. over the past several years. This has included assessment of the current threat of this pathogen to the local industry, assessment of seedborne viral transmission, and development of a new greenhouse screen to identify sources of resistance to Potato mop-top virus.