ABSTRACT
The Helminthosporium diseases or “leaf spot” are very widespread on both cool- and warm-season turfgrass species. Melting-out is potentially the most important disease of Kentucky bluegrass. Spots eventually appear on the leaf sheaths, and the fungus moves down and invades the crowns and roots of the grass plant. The turf should receive between 0.10 to 0.20 of an inch of irrigation every day. Moderate levels of nitrogen should be applied during warm weather, when the leaf spot is active. Potassium and phosphorus should be maintained at adequate levels as determined by soil tests. There are varieties of perennial ryegrass that are resistant to brown blight, and they should be used in preference to the susceptible varieties. The fungus survives the dormant period in infected tissue of living plants and in the infected dead tissue in the mat.
