Disease Note.

Survey of Kentucky for Potato Virus Y Strain N and Other Potyviruses in Tobacco. T. P. Pirone, Department of Plant Pathology, University of Kentucky, Lexington 40546. W. C. Nesmith, Department of Plant Pathology, University of Kentucky, Lexington 40546. Plant Dis. 78:754. Accepted for publication 4 March 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0754B.

The tobacco veinal necrosis strain of potato virus Y (PVYN) causes systemic necrosis of burley tobacco (Nicotiana tabacum L.) cultivars and may cause a complete loss of the crop. The geographical distribution of PVYN strains was limited to Europe and parts of Africa and South America but recently has been found in Canadian provinces that supply seed potatoes to Kentucky (1,2). A survey for PVYN was conducted in 1992; the endemic ordinary strain (PVY?) and two other potyviruses, tobacco etch (TEV) and tobacco vein mottling (TVMV), were included in the survey, both as a control for our survey methods and to obtain data on their incidence. Over 20,000 plants were sampled from 1,098 individual fields throughout (he state. A single plant was found to be infected with a PVY isolate that reacted with a highly PVYN-specific monoclonal antibody in ELISA tests, but the isolate did not cause necrosis on tobacco. ELISA tests revealed that PVY°, TEV, and TVMV were present in all districts of the state, and the highest incidence was in the major burley tobacco-producing regions. The incidence of PVY° was much higher than that found in a 1980 survey; this is consistent with industry observations of increasing incidence of PVY in the Kentucky tobacco crop