What is Dollar Spot?
Dollar spot is a common lawn disease usually occuring during the warm day/cool night conditions of late spring and late fall. It appears as small circles of bleached-out dead grass, 2-3 inches in diameter, which can coalesce into larger patches of dead grass. White, cobwebby mycelium may be present on the patches in the early morning with the dew. Dollar spot can be found in most grass species but likes Kentucky bluegrass the best.
How does dollar spot happen?
Dollar spot pops up when high moisture levels are present, especially when warm days followed by cool nights bring on a heavy dew. These conditions are most prevelant in the late spring and late fall. Frequent watering and excessive thatch or poor drainage will also encourage the disease. Low soil fertility will exascerbate a dollar spot outbreak.
How to deal with dollar spot
The best way to deal with dollar spot is to avoid conditions that can hasten it's onset or make conditions worse. Maintain healthy turf by mowing at a height of 2.5-3.5 inches, watering deeply and infrequently, and maintaining adequate fertility.
Although fungicides are available to treat dollar spot, they are not recommended for home lawns. A low rate application of quick release fertilizer is preferrable and effective in causing the grass to "grow out" of an out-break.
Dethatch if necessary and core aerate occasionally to improve drainage and water movement through the soil.
For future prevention of dollar spot infestation, overseed with disease resistant cultivars of grass.