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