Brown Patch

Brown patch is a turfgrass disease that is caused by the Rhizoctonia species fungus. This turfgrass disease is most common Brown patch can be found in all of the cool season turfgrasses found in the United States. Brown patch is most devastating to: Bentgrass (Agrostis sp.), ryegrass (Lolium sp.), Annual bluegrass (Poa annua), and Tall fescue (Festuca arundinacea). Brown patch is also found in Kentucky bluegrass (Poa pratensis) and Fine fescue (Festuca sp.) but this is rare or does minimal damage. Brown patch is known as a foliar disease, so it does not have any effect on the crown or roots of the turf plant.

Brown patch symptoms differ depending on the various maintenance practices performed on the turfgrass (mowing height, fertilizer, watering, etc.) Symptoms on turfgrasses that are wet for extended periods and are closely mowed will produce a distinctive gray-purplish bordered ring "smoke-ring" that is up to 50 cm in diameter. While on taller cut grasses that are not wet for extended periods of time will begin to produce patches that can be several feet in diameter and may have a "frogeye" appearance. White mycelium can be found on dew-covered turf in the early part of the morning. On a closer look at the grass leaf blades (usually on Tall Fescue) you maybe able to see tan to brown small, irregular shaped lesions.