Beet Western Yellows Virus Is Not an Important Component of Potato Leafroll Disease in Canada and the United States. Peter Ellis, Research Scientists, Agriculture Canada Research Station, Vancouver, British Columbia, Canada V6T 1X2. Richard Stace-Smith, Research Scientists, Agriculture Canada Research Station, Vancouver, British Columbia, Canada V6T 1X2. Plant Dis. 77:718-721. Accepted for publication 19 February 1993. Copyright 1993 The American Phytopathological Society. DOI: 10.1094/PD-77-0718.

We tested 801 samples of potato leaves with leafroll-like symptoms for potato leafroll virus (PLRV) and beet western yellows virus (BWYV) using virus-specific monoclonal antibodies in triple-antibody sandwich enzyme-linked immunosorbent assay (TAS ELISA). The samples represented 32 cultivars and originated in eight Canadian provinces and 12 states in the United States. None of the samples tested positive for BWYV, whereas 774 (96.6%) tested positive for PLRV. Neither virus could be recovered via aphid (Myzus persicae) transfers to indicator hosts from 18 samples that tested negative for both viruses. Tubers collected from 134 of the samples were sprouted and retested by both TAS ELISA and a polyclonal antiserum-based double-antibody sandwich (DAS) ELISA. These tests confirmed the initial results. Absorbance readings, when different, were consistently higher in TAS ELISA than in DAS ELISA. Aphid transmission attempts confirmed the ELISA results. In other aphid transmission trials, we were unable to transmit any of seven isolates of BWYV from infected groundcherry (Physalis pubescens) to potato, which indicated that potato is not a host of BWYV.