Efforts to control the disease by turf managers generally failed because of the lack of information on the cause of the disease and the effectiveness of specific disease management practices. Research Research initiated during the 1980s identified the cause of the disease, determined the effectiveness and timing of fungicide applications needed to control the disease, and determined the susceptibility of some bluegrass cultivars to the pathogen. The fungus Leptosphaeria korrae is the cause of this newly recognized disease, now called necrotic ring spot. Several fungicides suppress the growth of the pathogen in the laboratory, and field studies have resulted in the registration of one fungicide that, when applied once in the spring, provides season-long control of the disease. Several cultivars of Kentucky bluegrass appear to be resistant to necrotic ring spot.
Current research seeks to identify additional resistant cultivars to reduce the use of fungicides.