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ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Publications at this Location » Publication #240898
Title: Susceptibility of Different Potato Cultivars to Purple Top Disease

Author
item Munyaneza, Joseph - Joe
item Crosslin, James
item Buchman, Jeremy

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2009
Publication Date: 8/16/2009
Citation: Munyaneza, J.E., Crosslin, J., Buchman, J.L. 2009. Susceptibility of Different Potato Cultivars to Purple Top Disease. American Journal of Potato Research. 86:499-503.

Interpretive Summary: In 2002, Columbia Basin potato growers in Washington and Oregon began to experience serious outbreaks of potato purple top disease that have caused significant yield losses and reductions in tuber quality. Despite the increasing importance of the problem, little is known about the impact of purple top disease on potato in the Pacific Northwest. Researchers at USDA-ARS Wapato and Prosser, WA assessed the susceptibility of important potato cultivars grown in the Columbia Basin to purple top under field conditions. It was determined that Russet Norkotah, Ranger Russet, and Umatilla Russet were relatively highly susceptible to purple top. Russet Burbank and FL1967 showed some resistance to the disease. Alturas, Shepody, and FL 1879 were moderately susceptible to purple top. Information from this study will help potato growers reduce damage caused by potato purple top through selection of cultivars that are resistant to or tolerant of the disease and by protecting susceptible varieties against the beet leafhopper, the disease insect vector.

Technical Abstract: In 2002, Columbia Basin potato growers in Washington and Oregon began to experience serious outbreaks of potato purple top disease that have caused significant yield losses and reductions in tuber quality. It was determined that the beet leafhopper-transmitted virescence agent (BLTVA) phytoplasma is the causal agent of the disease in the Columbia Basin and that this pathogen is transmitted by the beet leafhopper. Little is known about the impact of purple top disease on potato in the Pacific Northwest. Trials were conducted in 2006, 2007, and 2008 to assess susceptibility of important potato cultivars grown in the Columbia Basin to purple top under field conditions. Eight potato cultivars were planted in small field plots and exposed to naturally occurring BLTVA-infected beet leafhoppers. Disease incidence was recorded at the end of the growing season. Purple top foliar symptoms were observed in all the tested cultivars, and plant samples collected and tested by PCR confirmed the presence of BLTVA. Results also showed significant differences in susceptibility of the cultivars to purple top. Disease incidence in leafhopper-exposed plots ranged from 1.5 to 49.3% among cultivars. Russet Norkotah, Ranger Russet, and Umatilla Russet were relatively highly susceptible to purple top, with average disease incidence of 33.5, 23.3, and 19.4%, respectively. Russet Burbank and FL1967 showed some resistance to purple top as they had the lowest plant disease incidence of 2.3 and 4.4%, respectively. Alturas, Shepody, and FL 1879 were moderately susceptible to purple top, with average disease incidence of 12.8, 8.0, and 9.3%, respectively. Information from this study will help potato growers reduce damage caused by potato purple top through selection of cultivars that are resistant to or tolerant of the disease and by protecting susceptible varieties against the beet leafhopper.