Detection of Potato Leafroll Virus in Leaf and Aphid Extracts by Dot-Blot Hybridization. Oney P. Smith, U.S. Department of Agriculture, Agricultural Research Service, Foreign Disease–Weed Science Research Unit, Frederick, MD 21702. V. D. Damsteegt, C. J. Keller, R. J. Beck, and A. D. Hewings. U.S. Department of Agriculture, Agricultural Research Service, Foreign Disease–Weed Science Research Unit, Frederick, MD 21702; and USDA-ARS, Crop Protection Research Unit, Department of Plant Pathology, University of Illinois, 1102 South Goodwin Avenue, Urbana 61801. Plant Dis. 77:1098-1102. Accepted for publication 4 June 1993. Copyright 1993 The American Phytopathological Society. DOI: 10.1094/PD-77-1098.

Cloned cDNA to potato leafroll virus (PLRV) RNA was evaluated for detection of PLRV in virus-infected samples from four states and the countries of Colombia and Russia. The use of formaldehyde was 32 times more effective than formamide for denaturing leaf tissue extracts in the dot-blot assay, and the sensitivity of the technique was estimated to equal that of the enzyme-linked immunosorbent assay (ELISA) for PLRV detection. These results, use of a commercial leaf sap extractor, detection of virus in bulk aphid samples, and use of the assay in a nonradioactive format demonstrate that the technology has potential for large-scale disease screening programs.