Gray leaf spot is a foliar disease that affects perennial ryegrass and tall fescue. It is caused by a fungal pathogen (Pyricularia grisea) that readily infects and kills leaf blades. Leaf infections can progress into the crown area, resulting in death of individual plants. Moderate outbreaks of gray leaf spot result in clusters of thin, off-colored turf. Severe outbreaks, however, will result in the death and decay of extensive areas and ruin the entire turf stand.The map in Figure 1 helps describe the range of the disease in the Midwest and the potential frequency for outbreaks. The purple area defines a transition zone where the disease occurs sporadically. Outbreaks are more likely to occur in the red area. Gray leaf spot has not been reported in the blue area.

Disease Characteristics
From a distance, initial gray leaf spot outbreaks resemble drought stress. Affected turf often assumes a blue-gray cast and is noticeably thinned by dead and decaying leaf blades. Close inspection reveals blighted leaves, some with distinct lesions. Because the epidemic progresses so rapidly, the leaf spot symptom may be short-lived. When leaf spots are apparent, they may be confused with symptoms caused by the other leaf spot diseases, therefore, accurate identification is critical. The importance of obtaining an accurate identification as soon as possible cannot be over emphasized. The disease spreads so fast and control is so expensive that a delay in identification can be very costly.

Solutions
3336, 26/36, Headway, Heritage, Disarm, Disarm G, Insignia, TM+CTN, T-Methyl, Banner Maxx, PimeraONE Propiconazole