Association of Gaeumannomyces graminis var. graminis with a St. Augustinegrass Root Rot Disease. M. L. Elliott, University of Florida, Fort Lauderdale Research and Education Center, Fort Lauderdale 33314. A. K. Hagan, and J. M. Mullen. Department of Plant Pathology, Auburn University, Auburn, AL 36849. Plant Dis. 77:206-209. Accepted for publication 28 July 1992. Copyright 1993 The American Phytopathological Society. DOI: 10.1094/PD-77-0206.

A patch disease of St. Augustinegrass (Stenotaphrum secundatum) characterized by a severe root rot was observed during the summer and fall on residential lawns and sod production fields in Florida during 1988–1991 and in Alabama during the summer of 1991. Gaeumannomyces graminis var. graminis was consistently isolated from symptomatic roots and stolons. Koch’s postulates were fulfilled for this pathogen with St. Augustinegrass grown in a greenhouse. The disease was observed on a range of cultivars growing on numerous soil types, suggesting the pathogen is widely distributed. In addition, the disease was observed on lawns that had been established for only 1 yr as well as lawns established for over 10 yr.