Isoalates of fungi from aquatic weeds were screened in 1996 for pathogenicity on both hydrilla and water milfoil. This endeavor is summarized in a separate report in this document. Additioal isolates of Puccinia jaceae teliospores from Iran were tested for viability along with a Bulgarian isolate that formed teliospores in the greenhouse. These results also are described in a separate report in this document. A virus disease of velvetleaf collected in the PRC was established from dried, pressed leaves, and it has been increased in two Nicotiana spp. and returned to velvetleaf.
Plans are to identify the virus and conduct host range studies.
An unknown rust fungus was provided by Dr. Dave Kazmer from the University of Wyoming. It was an only occurrence during a survey of musk thistle for insects. Examination of the spores microscopically and susceptibility of musk thistle provide the evidence for identification of this pathogen as Puccinia carduorum . This is the first report of P. carduorum on musk thistle in Wyoming and the farthest west that it has been recorded. Yellow starthistle tissue infected by an MLO was provided from Italy along with healthy tissue.