Identification of an Isolate of the Andean Strain of Potato Virus S in North America. S. A. Slack, Associate Professor, Department of Plant Pathology, University of Wisconsin, Madison 53706. Plant Dis. 67:786-789. Accepted for publication 22 December 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-786.

An unusual isolate of potato virus S (PVS-An) was recovered from potato (Solanum tuberosum ‘Red La Soda’). In contrast with most described PVS isolates, PVS-An is aphid-transmissible and invades Chenopodium quinoa systemically after inducing chlorotic local lesions. PVS-An was transmitted (10 aphids per plant) at about 10% efficiency in tests that included transmission of purified PVS-An by aphids fed through artificial membranes. The systemic invasion of C. quinoa is of interest because the PVS isolates reported from Europe and North America induce only a local lesion response. Recent evidence indicates that aphid-transmissibility and systemic invasion of C. quinoa are common features of isolates of the Andean strain of PVS. PVS-An conforms to the description of the Andean strain of PVS.

Keyword(s): carlavirus.