Problem: Leaf Smuts
This grass disease is caused by two fungus organisms (Ustilago striiformis, or stripe smut, and Urocystis agropyri, or flag smut) that attack many kinds of turfgrass but are most prevalent on Kentucky bluegrass. The spores infect the plant''s crown and adjoining underground stems. The fungus then grows throughout the plant''s tissues. The disease is most active in cool weather (50° to 60°F). Diseased plants die during the next period of hot weather. Leaf smuts are favored by high soil fertility and excessive watering.
Leaf smut is difficult to eliminate completely, but its severity can be lessened. Follow recommended lawn care practices to maintain a healthy and vigorous lawn.