Pathogen: Rhizoctonia solani
Host: Annual Bluegrass, Creeping Bentgrass, Colonial Bentgrass, Velvet Bentgrass, Kentucky Bluegrass, Fine Fescue, Tall Fescue, Perennial Ryegrass
Environmental Requirements: 80-95 F, high moisture, high N
Stand Symptoms: circular blighted areas, with “smoke ring” at margin (Usually)
Plant Symptoms: water soaked blight on leaves, drying to dark brown
Fungal Signs: whitish, cottony mycelium on affected turf when moisture is present. Hyphae have right-angled branching and are constricted at the branch point. There is also a septum near the branch point.
Environmental Modification: avoid N fertilization during hot humid weather
Plant Resistance: Tall Fescue and Colonial Bentgrass most susceptible