Lawn Diseases - Red Thread Disease
Red Thread lawn fungus appears in turf as small pinkish-red spots or patches, usually in later May and June when temps are high, and humidity is higher. Infected areas eventually turn light tan, and the leaf tips or margins may be covered with fine pink to red threads, giving the turf an overall pink coloration.
Red Thread, also known as "Pink Patch," occurs in the cooler and more humid areas of the Pacific Northwest, Northeast, and Midwest. It is most severe on slow growing, nitrogen- deficient turf grass during damp weather. We have had these exact conditions here in Chicago and Northwest Indiana these past few weeks of early June. (lots of rain, heat and humidity)
Susceptible turf grasses include bluegrasses, bent grass, fescues, Bermuda grass, and perennial ryegrass. The fungus actually over winter's on the leaves and in the debris of previously infected plants. The leaves and leaf sheaths appear to be the only grass parts that become diseased.