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POSTERS: Pathogenicity and host specificity

Spread and host-specificity of tomato ringspot virus on sweet cherry (Prunus avium) in Oregon
Lauri Lutes - Oregon State University. Jay Pscheidt- Oregon State University

Oregon ranks second among U.S. states for sweet cherry (Prunus avium) production. Recent statewide surveys identified the presence of the dagger nematode (Xiphinema spp.) transmitted tomato ringspot virus (ToRSV) in Hood River, The Dalles, and the Grande Ronde Valley. Little is known about this virus on sweet cherry. A ToRSV-infected orchard in The Dalles was assessed for foliar enations, rosetting, dieback and rapid decline symptoms. Visual assessments of symptoms on 1500 trees were made by ranking severity on a 0-4 scale (0 = no symptoms, 4 = most severe). Leaves were collected from a sub-region of 400 trees for diagnostic testing using a ToRSV-specific double-antibody sandwich ELISA (Agdia, Inc., Elkhart, IN). A section of 50 trees was selected for nematode sampling within the sub-region. A composite of four soil cores from around each tree base were collected in October 2018. Nematodes were extracted by sugar flotation and identified with microscopy. The visual assessment of symptoms matched 92.9% (n = 352) of the ELISA results. A total of 28 mismatches occurred, 26 (6.9%) were positive when no symptoms were observed and 2 (0.5%) tested negative that had symptoms. Dagger nematodes were present in soil near trees with and without ELISA-positive ToRSV diagnoses.Host-specificity of the ToRSV sweet cherry isolate is being evaluated in a field study by interplanting apple, peach, cherry, blueberry, raspberry, and grape around ToRSV-infected sweet cherry trees.