|Swisher Grimm, Kylie
|WOHLEB, CARRIE - Washington State University
|WATERS, TIM - Washington State University
|FROST, KEN - Washington State University
Submitted to: Potato Progress
Publication Type: Trade Journal
Publication Acceptance Date: 7/19/2018
Publication Date: 7/20/2018
Citation: Swisher Grimm, K.D., Wohleb, C., Waters, T., Frost, K. 2018. 2017 potato symptoms in the Columbia Basin: Is there a pathogenic cause?. Potato Progress. 18(10):1-4.
Interpretive Summary: Roughly 25 percent of the United States potatoes are grown in the Columbia Basin of Washington and Oregon. A researcher at the USDA-ARS in Prosser, Washington, in collaboration with Washington State University and Oregon State University, sought to identify a pathogenic cause for symptoms of leaf distortion, purpling terminals, and stem blistering identified on potato plants in the Columbia Basin during the 2017 growing season. Using both greenhouse grafting techniques and routine molecular diagnostic analyses in the laboratory, no pathogen was identified that correlated with these symptoms. While additional studies are required to validate these results, these results suggest that the causal agent of these symptoms could be due to pest pressure or environmental factors.
Technical Abstract: Starting in early- to mid-July of the 2017 growing season, potato crops across the Columbia Basin began showing symptoms of purpling terminals, distorted leaves with warping, crinkling, and holes, and stems with bumps or blisters, often accompanied with spots of necrosis. Symptoms increased as the season went on, and by mid-August, it was difficult to find a field without symptoms. Symptomatic fields were typically 90% affected, or higher, depending upon the variety. Symptomatic foliar tissue was collected from several commercial and research fields across the Columbia Basin, and taken to the USDA-ARS research laboratory in Prosser, WA, for grafting and molecular analyses. None of the symptoms appeared graft-transmissible, as there was no correlation between field symptoms and recipient plant symptomology. In addition to this, standard molecular analyses did not detect any common bacterial or viral pathogens that correlated with these field symptoms. Results from this first year of study indicate that the causal agent of the symptoms of leaf distortion, purpling, and stem blistering in 2017 were not pathogenic in nature.