VIEW ARTICLE

Discovery and Characterization of Elm Mosaic Virus in Iowa. R. E. Ford, Professor, Department of Botany and Plant Pathology, Iowa State University, Ames 50010; H. E. Moline(2), G. L. McDaniel(3), D. E. Mayhew(4), and A. H. Epstein(5). (2)(4)(5)Graduate Research Assistants, and Associate Professor, respectively, Department of Botany and Plant Pathology, Iowa State University, Ames 50010; (3)Graduate Research Assistant, Department of Horticulture, Iowa State University, Ames 50010. Phytopathology 62:987-992. Accepted for publication 1 March 1972. DOI: 10.1094/Phyto-62-987.

A virus was isolated from leaves of Moline elm exhibiting ringspot mosaic symptoms and enations. It was serologically identical to type strain elm mosaic virus (EMV). This is the first report of EMV in Iowa. This isolate of EMV was examined with an electron microscope in shadowed and negatively stained preparations, and was seen associated with necrotic ringspots in fixed preparations of inoculated Chenopodium quinoa leaves. The particle is a polyhedron of 19-nm diam. New hosts of EMV are reported. Density gradient and analytical ultracentrifugation revealed that EMV was composed of particles of three densities: top, middle, and bottom components of S_20,w 45, 65, and 92, respectively. Infectivity was associated only with middle and bottom components. The buoyant density of the major bottom component was 1.3328 g/cm³.