First Report of Gray Leaf Spot (Pyricularia grisea) on Perennial Ryegrass (Lolium perenne) in New England.

Pyricularia grisea (Cooke) Sacc. causing significant damage in perennial ryegrass (Lolium perenne L.) was first observed on a golf course in eastern Maryland in 1985 by P. H. Dernoeden, but there is no published account. The first published report of the problem was from southeastern Pennsylvania in 1991 (1). There were scattered reports of gray leaf spot in several other states in 1991. A more severe and widespread epidemic occurred under similar environmental conditions throughout the mid-Atlantic region in 1995 and has reoccurred to some extent annually since then in an expanding area throughout the United States. This report documents the expansion of the northern range of the epidemic into New England. Samples of perennial rye-grass with gray leaf spot from golf courses in three towns in Connecticut (Norwich, Stratford, and Willamantic) and one in Rhode Island (West Warwick) were submitted to the diagnostic labs at the universities of Massachusetts and Rhode Island beginning on 22 September 1998. Severe gray leaf spot was observed in perennial ryegrass fairways and roughs, especially where new seedlings were present, causing turf loss exceeding 50% in some areas. Diagnosis of this now familiar disease is based on the presence of abundant sporulation of the pathogen on infected tissue, distinctive leaf symptoms, and rapid foliar blighting of only perennial ryegrass in plantings of mixed turfgrass species. Golf course superintendents in New England with perennial ryegrass may have to extend their late-season fungicide applications to accommodate this new and destructive late-summer and fall disease. Reference: (1) P. J. Landschoot and B. F. Hoyland. Plant Dis. 76:1280, 1992.