Necrotic Ring Spot

From Turf Wiki

• Pathogen: Ophioshpaerella korrae (J. Walker & A. M. Sm.)

• Common Names: Necrotic Ring Spot

• Climatic Zone: Temperate, Subtropical, and Tropical

• Geographic Distribution: North America, Europe, East Asia, Australia, Africa, South America

• Favorable Conditions: Conditions may be either cool and wet or hot and dry. Can be brought about by a nutrient deficiency

• Hosts:Creeping Bentgrass, colonial bentgrass, velvet bentgrass, Perennial Ryegrass, Annual Bluegrass (Poa annua), bermudagrass (Cynodon dactylon), Tall Fescue, Kentucky Bluegrass, St. Augustinegrass, zoysiagrass, fine fescues

• Symptoms: Small light green patches, 2"-4" (5-10 cm) in diameter, leaves turn reddish brown to a bronze color, blackening of roots and rhizomes, with recolonization of grass at center of the patch