Disease Note

A New Geminivirus Infecting Potatoes in Venezuela. E. J. F. Roberts, Department of Pure and Applied Biology, Imperial College of Science and Technology, London, England. K. W. Buck, and R. H. A. Coutts, Department of Pure and Applied Biology, Imperial College of Science and Technology, London, England. Plant Dis. 70:603. Accepted for publication 3 January 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-603a.

Solanum tuberosum L. subsp. tuberosum plants grown in north-central Venezuela showed a bright yellow mosaic, leaf distortion, and stunting (mosaico amarillo de la papa). Studies of infected material supplied by R. Lastra showed the responsible pathogen to be a geminivirus, which we have named potato yellow mosaic virus (PYMV). PYMV is transmitted by the whitefly Bemisia tabaci (Genn.) and is mechanically transmissible to Lycopersicon, Nicotiana, and Petunia spp. but not to potatoes. PYMV was successfully transmitted from infected tobacco plants by scion-grafting healthy potato apices, stem cuttings of which were grown to maturity. Isolated virions contained circular single-stranded DNAs characteristic of the geminivirus group. A number of other double-stranded DNA forms found in infected tissue may correspond to viral replicative intermediates. Work is in progress on molecular characterization of PYMV.