PARTIAL HOST-RANGE OF THE HIGH-PLAINS VIRUS OF CORN AND WHEAT

Barley (Hordeum vulgare), cheat (Bromus secalinus), corn (Zea mays), o at (Avena sativa), rye (Secale cereale), and wheat (Triticum aestivum) were infected by a Kansas isolate of the High Plains virus (HPV) in g reenhouse experiments, but several other grass species were not. Infec tion of a host was dependent upon wheat curl mite numbers. Although bo th green foxtail (Setaria viridis) and yellow foxtail (S. glauca) are found naturally infected by HPV, only yellow foxtail could be infected in greenhouse experiments. Field sampling (1994 to 1996) of symptomat ic yellow foxtail showed that it is a good indicator of the presence o f HPV, with 252 of 278 symptomatic plants testing positive in enzyme-l inked immunosorbent assay (ELISA) for HPV, 2 of 278 for American wheat striate mosaic virus, and 1 of 278 for johnson grass mosaic virus, wh ereas 23 of 278 symptomatic plants were negative for all viruses teste d by ELISA and were not infectious in back-assays.