Beet Western Yellows Virus - A Major Component of Some Potato Leaf Roll-Affected Plants

Abstract

Beet western yellows virus (BWYV) was isolated from potato stocks with typical potato leaf roll (PLR) symptoms. Virus isolates from potato that induce leaf rolling, interveinal chlorosis, petiole epinasty and reduction in leaf size in Physalis floridana and interveinal chlorosis on Capsella bursa-pastoris were strains of BWYV. Isolates differing in host reaction and serological characteristics were found in individual potato plants indicating a complex etiology for the PLR syndrome. In addition to potato and other solanaceous hosts, 1 isolate was transmitted to and recovered from species in the Boraginaceae, Chenopodiaceae, Compositae, Cruciferae, Leguminosae, Malvaceae and Portulachceae. The BWYV isolates induce primary leaf roll symptoms in PLRV-free and virus-free potato cultivars, indicating that these isolates might easily be confused with typical PLRV. Preliminary serological data indicate that there are several serotypes of BWYV in potato that differ from each other and from PLRV in serological reactions. Serological testing for PLRV occurrence would probably give misleading information. The broad host range of these BWYV isolates raises questions about the reinfection of virus-free potato stocks from infected wild hosts in isolated areas.