Impact of Ergot on Kentucky Bluegrass Grown for Seed in Northeastern Oregon. Steve C. Alderman, Plant Pathologist, USDA-ARS National Forage Seed Production Research Center, Corvallis, OR 97331. Dale D. Coats, Research Assistant, and Fred J. Crowe, Superintendent, Central Oregon Agricultural Experiment Station, Madras, OR 97741. Plant Dis. 80:853-855. Accepted for publication 30 April 1996. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1996. DOI: 10.1094/PD-80-0853.

The impact of ergot on production of Kentucky bluegrass grown for seed in northeastern Oregon was determined. High levels of ergot occurred in only two of the six cultivars examined. In susceptible cultivars as many as 504 sclerotia per gram of seed were detected. This equated to 47% ergot by weight, or 25% infected seed. Ergot severity (percent sclerotia by weight) in Kentucky bluegrass seed in 1991 to 1994 was estimated at 0.20, 0.04, 0.07, and 1.15%, respectively, based on total seed production in northeastern Oregon. Percent seed replaced by sclerotia in 1991 to 1994 was 0.05, 0.01, 0.03, and 0.44%, respectively. A significant relationship between ergot severity and yield was not delected. However, a 9% reduction in marketable seed weight occurred when seed lots contaminated with ergot were recleaned to meet purity standards.