Isolation of Tomato Spotted Wilt Virus from Hydrangea and Four Weed Species. T. C. Allen, Professor, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. J. P. McMorran, Research Assistant, and E. A. Locatelli, Graduate Research Assistant, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. Plant Dis. 67:429-431. Accepted for publication 8 November 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-429.

Field selections of Hydrangea macrophylla 'Imaculata,' tansy ragwort (Senecio jacobea), puncture vine (Tribulus terrestris), purslane (Portulaca oleracea), and cutleaf nightshade (Solanum triflorum) were infected with tomato spotted wilt virus (TSWV). Hydrangea exhibited ring spot symptoms in the field, and tansy ragwort from the field developed ring patterns when transplanted and maintained in a greenhouse. Both TSWV and hydrangea ringspot virus (HRSV) are associated with ring spots on hydrangea and local lesions on Gomphrena globosa, the most sensitive and commonly used indicator plant for HRSV. Therefore, special attention must be paid to correctly identify the virus involved in symptom formation in these plants.