TechNotes Tips - 06.27.02

Brown patch is active on many tall fescue lawns through the transition zone. This disease is especially severe during hot humid weather, which is currently occurring through much of the Midwest and southeastern United States. Symptoms appear as light circular brown to black patches. The center of the patches may appear green. On tall fescue leaf lesions are often present and serve as a diagnostic key. The leaf lesions appear circular initially but can expand in size and shape. The lesions appear tan but where the lesion interfaces with the green tissue, a dark brown to black staining occurs. During periods of hot humid conditions, minimize applications of nitrogen, since this nutrient can enhance the severity of brown patch.

Mowing should be limited on turfs that are wilting or dormant. Damage to the leaf blades can occur from mower equipment traveling across the turf. Most damage that does occur to the turf will recover once adequate moisture is present and new leaves are generated.