Dollar spot causes sunken, circular patches that measure up to 5 cm in diameter on golf greens and several inches on higher mown turf.
The patches turn from brown to straw colour and may eventually coalesce, forming irregularly shaped areas. Infected leaves may display small lesions that turn from yellow-green to straw colour with a reddish-brown border. The lesions can extend the full width of the leaf. Multiple lesions may occur on a single leaf blade.
Dollar spots coalescing.
All species of warm and cool-season turfgrass.
Conditions favouring disease
Dollar spot is favoured by temperatures between 15°C to 30°C and continuous high humidity.
This disease is particularly favoured by warm days, cool nights and intense dews.
It is more prevalent in areas with low levels of nitrogen and its effects are more severe in drier soils.
Integrated turf management
Use an adequate level of nitrogen, particularly in the spring and early summer.
Mow grass at regular intervals.
Increase the air circulation.
Irrigate turf deeply and as infrequently as possible to avoid drought stress.
Remove dew from the turf early in the day.
Convert to a turfgrass cultivar (especially for bentgrass) that is more tolerant to dollar spot.
Apply contact and/or penetrant fungicides on a preventive basis.