First Report of Pyricularia oryzae Causing Gray Leaf Spot of Perennial Ryegrass (Lolium perenne) in Oregon

Gray leaf spot of perennial ryegrass (Lolium perenne), caused by Pyricularia oryzae, is a devastating turfgrass disease in many regions of the United States. In 2021, P. oryzae was detected for the first time in Oregon, causing disease on a perennial ryegrass athletic field. This report describes the occurrence of gray leaf spot and pathogenicity testing on the original infected cultivar mixture. The confirmation of this pathogen in Oregon could have management implications for turfgrass managers of the state.