Identification of Viruses and Mycoplasmas in Maize by Use of Light Microscopy. M. A. Overman, Instructor, Department of Mathematics and Computer Science, University of Tennessee at Martin, Martin 38237. N. J. Ko, and J. H. Tsai. Visiting Professor, Agronomy Department, University of Florida, Gainesville 32611; and Professor, University of Florida, IFAS, Fort Lauderdale Research and Education Center, Fort Lauderdale 33314. Plant Dis. 76:318-322. Accepted for publication 1 October 1991. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0318.

Maize tissues infected with maize dwarf mosaic virus (MDMV) strain A or B, maize stripe virus (MStpV), maize mosaic virus (MMV), maize rayado fino virus (MRFV), maize chlorotic dwarf virus (MCDV), maize bushy stunt mycoplasma (MBSM), or corn stunt spiroplasma (CSS) were studied by light microscopy. Intracellular inclusions in stained epidermal strips were uniquely associated with infection by MDMV-A, MDMV-B, MStpV, or MMV. For MStpV identification, paradermal sections of the leaf sheath were better sources than such sections of the leaf blade. Both irregular and granular inclusions were found in parenchyma and phloem cells of leaf sheaths, leaf veins, and roots infected with MRFV. The phloem-inhabiting pathogens MCDV, MBSM, and CSS were found in longitudinal sections of the midrib and root. Stomata in epidermal strips of leaves infected with CSS showed a unique type of deformity. Light microscopy offers a rapid technique for detection and identification of maize viruses and mycoplasmas.