IDENTIFICATION OF THE SCMV-D VIRUS OF SUC ARCANE INFECTING ST AUGUSSTIN GRASS IN VENEZUELA

A virus isolate collected in a commercial crop of St. Augustine grass in Turmero, Aragua State, was mechanically inoculated to some differen tial hosts for its identification The virus infected different sorghum (Sorghum bicolor) cultivars, maize (Zea mays) and sugarcane (Saccharu m officinarum) cvs CP-31294 and CP-31588, but it didn't infect oat (Av ena sativa), barley (Hordeum vulgare), wheat (Triticum aestivum), john songrass (Sorghum halepense), and some dicotyledonous species. The the rmal inactivation point of the virus was 55-60 degrees C, the dilution end point was 10(-3)-10(-1), and the longevity in vitro was 12-24 h a t 27 degrees C. The virus was transmitted from sorghum to sorghum in a non-persistent manner by the aphid Rhopalosiphum maidis, but it was n ot transmitted through sorghum seed Electron microscopy revealed flexu ous rod's 730-800 nm long. Citoplasmic inclusions of the pinwheel, scr oll and laminated aggregates types were found in cells of maize infect ed with the virus. It was distantly related to SCMV-A and MDMV-V, but mere closely to SCMV-D when tested with antisera to the three strains by double-diffusion tests. On the basis of all used identification cri terions, the St. Augustine grass virus isolate corresponds to SCMV-D. This is the first report of SCMV-D in Venezuela. S. secundatum is repo rted, apparently, for the first time as a natural host of SCMV-D.