With the occurrence of hot humid weather and nighttime temperatures remaining above 70 F, it is not surprising then to see Brown patch (Rhizoctonia solani)active especially in shaded or low-lying areas. Hot humid weather with nighttime temperatures above 70 F can produce classic brown patch symptoms on creeping bentgrass or creeping bentgrass/Poa annua greens.
Symptoms normally appear as circular areas with ranging from several inches to a yard in diameter. The patches appear as a light tan color. If the pathogen is active a "smoke ring" occurs on the outer edge. Cultural controls include fertilizing with a minimal amount of nitrogen but adequate phosphorus and potassium, and providing surface and subsurface drainage to remove excessive water. Enhancing air movement around the turf at risk can reduce disease severity. In addition, practices that help minimize the accumulation of thatch make conditions less favorable for pathogen development.