Dollar spot is caused by the fungal pathogen Sclerotinia homoeocarpa, in the Sclerotiniaceae family. The pathogen blights leaf tissues but does not affect turf grass roots or crowns. The disease is a common concern on golf course turf, but is rare in sports turf and professional landscapes. Disease symptoms commonly result in poor turf quality and appearance. The disease occurs from early spring through late fall, but is most active under conditions of high humidity and warm daytime temperatures 59–86 °F (15–30 °C) and cool nights in the spring, early summer and fall. The disease infects by producing a mycelium, which can be spread mechanically from one area to another.