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ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Publications at this Location » Publication #396090
Research Project: Developing New Potatoes with Improved Quality, Disease Resistance, and Nutritional Content

Location: Temperate Tree Fruit and Vegetable Research

Title: Detection of potato mop-top virus in potato seed lots entering Washington State

Author
item Swisher Grimm, Kylie
item Quick, Rich
item Cimrhakl, Launa
item BROWN, CHARLES - Former ARS Employee
item PAVEK, MARK - Washington State University

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2022
Publication Date: 10/20/2022
Citation: Swisher Grimm, K.D., Quick, R.A., Cimrhakl, L.L., Brown, C., Pavek, M.J. 2022. Detection of potato mop-top virus in potato seed lots entering Washington State. American Journal of Potato Research. 99:390-394. https://doi.org/10.1007/s12230-022-09889-w.
DOI: https://doi.org/10.1007/s12230-022-09889-w

Interpretive Summary: The tuber necrotic viruses, Potato mop-top virus and Tobacco rattle virus, cause internal tuber symptoms that can lead to economic losses for a grower. From 2016 through 2022, researchers at the USDA-ARS in Prosser, WA, in collaboration with Washington State University scientists, tested seed lots submitted to the Washington State University Seed Lot Trial for Potato mop-top virus and Tobacco rattle virus to determine if either pathogen enters commercial fields through infected seed. Tobacco rattle virus was nearly undetectable, while Potato mop-top virus was identified in the Washington State potato seed lots each year, ranging from 1.73 – 5.50%. Infected lots originated from across the U.S. and from Canada, indicating that virus infection is not limited to specific regions or seed producers. These results are concerning for commercial growers in Washington State, as the rate of transmission from seed to daughter tubers in these cultivars is unknown, and fields across the region are known to be infested with Spongospora subterranea, the vector of Potato mop-top virus.

Technical Abstract: For many years, potato seed lots have been tested for the presence of economically important pathogens such as Clavibacter michiganensis, Potato leafroll virus and Potato virus Y in an effort to curb the spread of these pathogens. Despite this effort, some pathogens like Potato virus Y, inevitably make it into commercial seed lots and require management by growers. Although knowledge on the prevalence of some pathogens in the commercial seed lots has increased over the last decade, assessment of two tuber necrotic viruses, Tobacco rattle virus and Potato mop-top virus, in these seed lots has been lacking. Over the course of seven years, four tubers from each commercial seed lot entered into the Washington State University Seed Lot Trial, conducted at the WSU Othello research unit, were assessed for these two viruses. Tobacco rattle virus was not found to be of concern, but 1.73 to 5.50% of seed lots tested positive for Potato mop-top virus each year. The infected seed originated from as many as five different U.S. states during a single year and originated from Canada in six of the seven years. Potato mop-top virus was found in seven seed growing regions and 23 different cultivars over the seven-year study. These results are concerning for commercial growers, as the rate of transmission from seed to daughter tubers in these cultivars is largely unknown, and fields across the region are known to be infested with Spongospora subterranea, the vector of Potato mop-top virus.