Figure 5. Dollar spot (right) compared to Pythium blight (left), both on creeping bentgrass. Irregularly shaped size and appearance of Pythium blight affected turf compared to that of dollar spot affected bentgrass. Dollar spots are smaller, about 5 cm (2 in.) in diameter, while Pythium blight affected patches are larger, in some cases 12 cm (5 or more in.) in diameter. In Pythium blight situations, smaller spots (highlighted with arrows in the photo) can coalesce and become larger patches of blighted turf overnight. Dollar spots will remain similar in size and not increase overnight. Upon closer inspection of the patches one would find characteristic dollar spot lesions on the turfgrass on the right, while single lesions would not be present on individual blades of grass on the left. Pythium blight affected turf would also appear “greasy”, while dollar spot infected turf would appear sunken and bleached. (Courtesy L.L. Burpee) BACK