This devastating fungus disease will blight leaves and crowns of susceptible perennial ryegrass causing large areas of dead turf when weather conditions are favorable. This is a relatively new disease in our region and whole lawns have been blighted by gray leaf spot in recent years.
Symptoms
Gray leaf spot symptoms develop in early to mid August. Small chocolate brown spots develop on leaves. The spots enlarge and develop a gray center with a yellow halo. Dying turf blades often develop a characteristic twist at the leaf tip that helps differentiate gray leaf spot from Pythium blight or brown patch. In mixed stands of cool season grasses perennial ryegrass will be blighted while other grasses including annual bluegrass is unaffected. Tall fescue can be spotted but is not killed and therefore is considered resistant.