Detection of Prunus Necrotic Ringspot and Prune Dwarf Viruses in Prunus Seed and Seedlings by Enzyme-Linked Immunosorbent Assay. G. I. Mink, Plant Pathologist, Washington State University, Irrigated Agriculture Research and Extension Center, Prosser 99350. M. D. Aichele, Plant Pathologist, Division of Plant Industries, Washington Department of Agriculture, Yakima 98901. Plant Dis. 68:378-381. Accepted for publication 31 October 1983. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-378.

Enzyme-linked immunosorbent assay (ELISA) was used to determine the incidence of Prunus necrotic ringspot (NRSV) and prune dwarf (PDV) viruses in lots of Prunus seed and seedlings used by commercial nurseries in Washington and Montana between 1981 and 1983. These viruses were found rarely, if ever, in seed or seedlings of P. armeniaca, P. besseyi, P. salicina, P. serotina, and P. tomentosa. The incidence of both viruses in noncertified P. mahaleb seed lots (both foreign and domestic) was below the 5% tolerance limit allowed by the tree fruit virus certification programs of both states. Although NRSV was rarely detected in P. cerasifera seed, the incidence of PDV in noncertified seed lots ranged between 1 and 53%. PDV was detected in only two of 1,000 P. cerasifera seedlings, however, indicating that most PDV-infected seed did not germinate. In noncertified P. avium seed lots, the incidence of PDV ranged between 0 and 58% and the incidence of NRSV ranged between 0 and 28%. The incidence of either virus in P. avium seedlings was dependent on the incidence found in the seed lots. Only an occasional virus-infected seed was found in noncertified P. persica seed lots from Europe, whereas the average incidence of PDV and NRSV in domestic seed lots was 10 and 17%, respectively. Although NRSV was detected in P. persica seedlings of various size classes and in ungerminated seed, PDV was detected only in ungerminated or partially germinated seed. Use of ELISA to monitor virus incidence in Prunus seed and seedlings provides nurseries with a valuable tool for reducing the incidence of seedborne viruses in Prunus rootstocks.