Phleospora idahoensis on native Festuca spp. in the northwestern Great Plains

Abstract

Cultural characters, spore morphology, and size indicated that a fungus consistently associated with culm and inflorescence lesions on the native fescues Festuca scabrella Torr., F. idahoensis Elmer, and F. ovina L. in Western Canada and northwestern United States was Phleospora idahoensis Sprague. The fungus was morphologically and culturally identical with P. idahoensis, which recently caused severe out-breaks of a stem eyespot disease in crops of the introduced creeping red fescue, F. rubra L. subsp. rubra, in northern Alberta and on the ‘Olds’ cultivar in central Alberta. The widespread occurrence of P. idahoensis in Western Canada and northwestern Great Plains suggests that it is endemic. The epidemiological implications for crops of introduced fescues of the occurrence of the pathogen on native species are considered.