Dollar Spot

All turf species

• Closely mowed areas – sunken circular tan coloured spots (less than 5 cm).
• May coalesce into larger areas – especially higher mowed turf.
• Closer inspection reveals water soaked lesions that will turn tan (hourglass) with definite reddish-brown margins.
• Infection will rarely progress to crown or kill plants completely despite leaves being totally blighted.
• May be confused with early Pythium Blight and Red Thread.
• Humid, cool conditions may see the development of white mycelial growth on infected tissue.

• Temperature ranges of 15°C to 30°C and continuous high humidity.
• Warm humid weather with cool nights that produce heavy dews.
• When the micro-climate temperature reaches 16°C the fungus resumes growth.
• Low nitrogen levels.
• More severe in dry soils.

• Preventative fungicide program.
• Provide adequate level of nitrogen, particularly in the spring and early summer.
• Mow grass at regular intervals.
• Reduce thatch.
• Increase air circulation.
• Irrigate turf deeply and as infrequently as possible to avoid drought stress.
• Remove dew from the turf early in the day.

This fungus overwinters as sclerotia and as a dormant mycelium in the crowns and roots of infected plants. Soil pH has little or no effect on Dollar Spot severity.