Also, after the grass has been killed, it becomes increasingly difficult to identify the cause. In many cases, microscopic examination by experts is required to accurately diagnose a turfgrass disease problem. Key to the identification of common turfgrass diseases. Group I. Grass affected in distinct patches. Individual patches 2 to 3 inches in diameter, leaf lesions present.
Diseased spots are light tan or straw-colored.
Light tan lesions may be found near the top of the grass blade. Fine, cobwebby, mycelial growth can be seen covering the spots in the early morning when dew is present. Individual patches usually larger than 2 to 3 inches in diameter, leaf lesions not present. Spring Dead Spot. Grass not affected in distinct patches.