Viruses Infecting Red Clover in Pennsylvania. K. T. Leath, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, U.S. Regional Pasture Research Laboratory, University Park, PA 16802. O. W. Barnett, Professor, Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29631. Plant Dis. 65:1016-1017. Accepted for publication 17 August 1981. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1981. DOI: 10.1094/PD-65-1016.

Red clover of different ages in Centre, Crawford, Lancaster, Westmoreland, and Wyoming counties was surveyed for viruses in 1979; Centre and Lancaster counties were surveyed again in 1980. Enzyme-linked immunosorbent assay was used to detect specific viruses in randomly selected and symptomatic plants. Results for the two survey years were similar. Bean yellow mosaic virus, the most common in all fields, produced more than 80% of all positive assays in both years. Alfalfa mosaic, red clover vein mosaic, clover yellow vein, and peanut stunt viruses were detected at much lower frequencies. Clover yellow mosaic virus was not detected. Incidence of viral disease increased rapidly from year of seeding to the following year; it then stabilized at levels ranging from 30 to 54% of the plants infected, even in stands seeded 4 yr earlier.