Incidence of Prunus Necrotic Ringspot Virus in Some Pennsylvania Peach Orchards and Nurseries. B. A. Jaffee, Department of Plant Pathology, Pennsylvania State University, Fruit Research Laboratory, Biglerville 17307. C. A. Powell and M. A. Derr, Bureau of Plant Industry, Pennsylvania Department of Agriculture, Harrisburg 17110. Plant Dis. 70:688-689. Accepted for publication 14 January 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-688.

Sixteen percent of 324 trees sampled in 12 commercial orchards (23–30 trees per orchard) were positive for Prunus necrotic ringspot virus (PNRSV) as determined by enzyme-linked immunosorbent assay. Among orchards, the median and range of PNRSV-infected trees were 6 and 0–83%, respectively. If data from all orchards were combined, there appeared to be a statistical correlation between incidence of virus and canker of the trunk or scaffolds. However, there was no apparent statistical relationship between the presence of virus and cankers if the two orchards with the highest incidence of PNRSV were removed from the data set. PNRSV incidence in three nurseries ranged from 0 to 10% and appeared to be related to the source of budwood and seed.