Differentiation of Sugarcane, Maize Dwarf, Johnsongrass, and Sorghum Mosaic Viruses Based on Reactions of Oat and Some Sorghum Cultivars. M. Tosic, Professor, Department of Plant Protection, Faculty of Agriculture, University of Belgrade, Beograd-Zemun 11080, Yugoslavia. R. E. Ford, D. D. Shukla, and J. Jilka. Professor and Head, Department of Plant Pathology, University of Illinois, Urbana 61801; Senior Principal Research Scientist, CSIRO, Division of Biotechnology, Parkville Laboratory, Parkville, Victoria 3052, Australia; and Graduate Research Assistant, Department of Plant Pathology, University of Illinois, Urbana 61801. Plant Dis. 74:549-552. Accepted for publication 16 December 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0549.

Different virus strains, formerly called sugarcane mosaic virus (SCMV) and maize dwarf mosaic virus (MDMV), were studied under the same experimental conditions. The objective was to determine if a differential set of oat and 11 sorghum cultivars would distinguish among the four viruses in the new taxonomic system now classified as SCMV, MDMV, johnsongrass mosaic virus (JGMV), and sorghum mosaic virus (SrMV). Fifteen well-characterized strains of these four were used in this study. These viruses are separable based on symptom expression in sorghum and oat. JGMV alone infects oat. Strains within MDMV and JGMV react uniformly in sorghum. SCMV strains differ in reactions on some sorghum cultivars. SrMV strains differ on two sorghum cultivars. These infectivity results clearly support the new taxonomy suggesting that, although helpful, it is not essential to have biochemical and serological laboratory capabilities to classify these 15 virus strains.