The grass turns light brown to straw-colored in circular spots from the size of a silver dollar to 6 inches during warm, wet weather in May to June or September to October. Dead spots may merge to form large irregular patches. Small blotches with reddish-brown borders appear on leaf blades. In the early morning before the dew dries, a white cobwebby growth may cover infected blades. Dollar spot attacks many kinds of lawn grasses but is most severe on bentgrass, bermudagrass, and Kentucky bluegrass.
Lawns troubled by dollar spot are usually under stress from lack of moisture and nitrogen. It seldom causes permanent damage, although the lawn takes several weeks or months to recover. Shoes, hoses, mowers, and other equipment spread the fungus. Keep grass as dry as possible. Water only in the morning, one or two times per week. Maintain proper nutrient levels; applying nitrogen will help the lawn recover if it has a nitrogen deficiency.