Management practices

• Preventative fungicide program during high risk periods.
• 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.

Fungicidal control

The following products have label recommendation for Dollar Spot control in Australia:  

Refer to label for full details.

Suggested Programme

Contact Syngenta for assistance in creating a custom GreenSure Plan for your course.

DOLLAR SPOT

Causal Agent

Sclerotinia homoeocarpa     

Susceptible Turfgrass

All turfgrass species 

Symptoms

• Closely mowed areas - sunken circular tan coloured spots (less than 5 cm).
• May coalesce into larger areas - especially higher moved 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 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.

Plate 1. High infection level of Dollar Spot on a bent green.

Conditions Favouring Disease

• 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.

General Comments 

• 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.

Distribution

Found in all states of Australia, particularly coastal areas