VIEW ARTICLE

Etiology

Pathogenicity on Walnut and Serological Comparisons of Cherry Leafroll Virus Strains. Adib Rowhani, Postgraduate research plant pathologist, ARS, USDA, Department of Plant Pathology, University of California, Davis, CA 95616; S. M. Mircetich, research plant pathologist, ARS, USDA, Department of Plant Pathology, University of California, Davis, CA 95616. Phytopathology 78:817-820. Accepted for publication 6 January 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/Phyto-78-817.

Cherry leafroll virus isolate W8 (CLRV-W8) from English walnut (Juglans regia) with blackline symptoms in California was closely related serologically to isolate CLRV-Wsp from symptomless walnut seedlings originally from Spain. These two isolates were very similar to, but distinguishable from, a third isolate from Italy (CLRV-WRS) that induced ringspots on leaves of English walnut. Comparison by immunodiffusion with CLRV isolates from cherry, golden elderberry, dogwood, and rhubarb revealed that among these isolates, the golden elderberry isolate was the most closely related to the three walnut isolates. In pathogenicity tests, all three walnut isolates (CLRV-W8, -Wsp, and -WRS) infected Hartley English walnut cultivar and caused blackline symptoms at the English walnut/Juglans hindsii graft union. Uninoculated control trees and trees inoculated with CLRV cherry and golden elderberry strains remained healthy and virus-free.