The spots may grow together into large areas. Lesions are bounded by a tan to reddish-brown margin. A white, cotton-like fungal mycelium growth may be seen on diseased grass during early morning hours, when dew is present. Dollar spot fungus overwinters as dormant mycelium and sclerotia in crown and roots of infected grass. Pieces of diseased plants are carried from place to place by mowers, sweepers, and other lawn maintenance equipment.
Prevention is the best method of disease control.
To prevent dollar spot or other lawn diseases from developing, practice the following disease control procedures. Maintain adequate moisture and nutrients. The severity of dollar spot can be reduced by maintaining a high level of nitrogen during periods when the disease is most prevalent. Prevent the buildup of thatch. Do not water in the late afternoon or evening because it prolongs the period of leaf wetness during cool nights when dew is likely to form on leaves.