Dollar spot

Small (1–6 cm) straw-colored, sunken circular spots. Look for hourglass-shaped bleached lesions with reddish-brown borders on leaf blades, and white cottony mycelium on dewy mornings.

Dollar spot causes silver dollar-sized spots in short cut turf and larger patches in higher cut turf. In higher cut turf, the lesions are hourglass shaped and tan with brown borders. In lower cut turf, the classic lesions may not be present.

Dollar spot is characterized by the presence of white cotton-like mycelium on the canopy, most prevalent early in the morning when dew is present. There are no spores associated with Clarireedia spp.

This fungus does not produce spores, but instead spreads through its mycelium. The mycelium is a network of hyphae, which are thread-like structures that are part of the fungus's vegetative growth. The mycelium grows through the leaf tissues of the turfgrass and forms small, hourglass lesions, which eventually cause the characteristic symptoms of dollar spot. The fungus also produces enzymes that break down the cell walls of the turfgrass, allowing it to consume the plant's nutrients. Dollar spot is most active in warm, humid weather and is most commonly found on golf course fairways, athletic fields, and home lawns.

Dollar spot is most common in late spring to early winter when there are moderate to warm daytime temperatures and cool nights. The disease thrives under conditions of prolonged leaf wetness, high canopy moisture, and high atmospheric humidity. It is more severe in dry soils but dew is required for infection.