Use of Enzyme-Linked Immunosorbent Assay Results in Efforts to Control Orchard Spread of Cherry Rugose Mosaic Disease in Washington. G. I. Mink, Irrigated Agriculture Research and Extension Center, Prosser, WA 99350. M. D. Aichele, Division of Plant Industry, Washington Department of Agriculture, Yakima 98901. Plant Dis. 68:207-210. Accepted for publication 29 August 1983. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-207.

Dormant flower buds from over 15,000 sweet cherry trees were submitted by Washington growers over a 3-yr period and tested by enzyme-linked immunosorbent assay (ELISA) for the presence of Prunus necrotic ringspot virus (NRSV). Approximately 28% of all trees tested were infected with NRSV, and about 20% of these were rated by ELISA as infected with strains causing cherry rugose mosaic disease (CRM). Most, but not all, CRM-infected trees examined for symptoms during the growing season showed one or more symptoms of the disease. In orchards planted with certified virus-free trees, nearly all trees rated by ELISA as CRM-infected showed severe fruit symptoms. In these orchards, diseased trees were reliably identified by ELISA during the winter months for removal before flowering. In orchards planted with noncertified trees, however, a variable percentage of the trees rated by ELISA as CRM-infected had mild leaf symptoms of no economic importance to growers, atypical symptoms, or no symptoms. Although ELISA results proved useful for detecting and mapping the distribution of NRSV in these orchards, growers were reluctant to remove trees solely on the basis of such results.