Disease Note.

First Report of Sugarcane Mosaic Virus Strain MB in Venezuela. C. M. D'Lima, Facultad de Agronomfa, Universidad Central de Venezuela, Apartado 4579, Maracay 2101, Venezuela. M. J. Garrido, Facultad de Agronomfa, Universidad Central de Venezuela, Apartado 4579, Maracay 2101, Venezuela. Plant Dis. 79:212. Accepted for publication 11 May 1994. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0212A.

Virus-like symptoms on maize (Zea mays L.) were observed at Danac Experiment Station, St. Javier, Yaracuy, in 1991. Naturally infected maize plants showed mild mottle, mosaic, and slight stunting. The virus was mechanically transmissible to maize and some differential sorghum (Sorghum bicolor (L.) Moench) cultivars (2), but it didn't infect johnsongrass (Sorghum halepense (L.) Pers.), oat (Avena sativa L.), or sugarcane (Saccharum officinarum L. cvs. CP-31294 and CP-31588). The thermal inactivation point of the virus was 50-55 C, the dilution end point was 10-2–10-3, and longevity in vitro was 1-2 days at 25-30 C. Flexuous rods 730 nm long were observed by electron microscopy in clarified viral concentrate from diseased plants. The virus was transmitted from sorghum to sorghum nonpersistently by Schizaphis graminum (Rondani). Reactions positive in agar double-diffusion tests to antisera specific for sugarcane mosaic virus strain MB (SCMV-MB) and negative to antisera specific for johnsongrass mosaic virus and maize dwarf mosaic virus strain A (supplied by D. D. Shukla and R. W. Toler) identified the maize virus isolate as SCMV-MB (1). This is the first report of this strain in Venezuela.