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Rapid Identification of Maize Stripe Virus. O. E. Bradfute, Department of Plant Pathology, Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691; J. H. Tsai, University of Florida, Fort Lauderdale Research and Education Center, Fort Lauderdale 33314. Phytopathology 80:715-719. Accepted for publication 25 January 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/Phyto-80-715.

Maize stripe virus (MStpV) was identified in maize leaves by either diagnostic symptoms or needle-shaped crystals. The symptoms consisted of chlorotic patterns of overlapping circles with distinct margins when magnified 3–10×. The crystals were found in abundance by phase-contrast light microscopy in sap from symptomatic leaf areas. The crystals were similar to crystals of MStpV noncapsid protein in appearance and in differential solubility and reacted with antiserum to MStpV noncapsid protein in immunofluorescence microscopy. Diagnostic symptoms and the crystals could be found readily in naturally and experimentally MStpV-infected maize plants with a wide range of gross symptom types and throughout disease development, but not in maize infected by other maize viruses, or mycoplasmas, or in maize with sorghum downy mildew. The crystals were found in MStpV-infected sorghum, itchgrass, and two species of annual teosinte. By the presence of diagnostic symptoms and the crystals in leaf samples, the distribution of MStpV or a similar virus in maize was confirmed in Botswana, Mauritius, Nigeria, Peru, and Venezuela, where MStpV has been reported previously, and extended to Argentina, Brazil, and Puerto Rico. Similar needle-shaped crystals were found in maize leaves infected with rice stripe virus, confirming the similarity of this virus to MStpV and suggesting that direct observation of needle-shaped crystals may also indicate the presence of other viruses in the rice stripe virus group.