Dollar Spot
Causal Agent
Lanzia spp.
Formerly Sclerotinia homoeocarpa.
What is Dollar Spot?
Dollar Spot disease is caused by a fungus that overwinters as sclerotia and as a dormant mycelium in the crowns and roots of infected plants. Turf that is infected with dollar spot will commonly show small, sunken, circular patches about 1.5cm to 5cm in diameter.
Soil pH has little or no effect on Dollar Spot severity.
What are the symptoms of Dollar Spot disease?
Symptoms of dollar spot disease include:
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Small, sunken, circular patches 1.5 to 5cm in diameter which appear bleached out
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The patches turn from brown to straw colour and may coalesce, into larger irregularly shaped areas.
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In the presence of dew, mycelium may be seen as a fine white cottony thread.
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Infected leaves may show small lesions that turn from yellow-green to straw colour with a reddish-brown border. These lesions can extend the full width of the leaf.
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Multiple lesions may occur on a single leaf blade.
Dollar Spot INFO SHEETWhat causes Dollar spot disease?
More recent information suggests that Dollar Spot is now caused by species of Lanzia and Moellerodiscus fungi. The causal pathogen of Dollar Spot was formerly known as Sclerotinia homoeocarpa. Microscopic identification of Dollar Spot is undertaken via its distinctive granulated hyphae which appear after a period of incubation.
What turfgrasses are especially susceptible to Dollar Spot disease?
All turfgrass species, predominantly cool season grasses.
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The most susceptible grass is – Crenshaw, SR1020.
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Bentgrass – Pennlinks, A1 & A4, Providence, L-93 and Penn G2 have shown superior tolerance
When does Dollar Spot occur?
Conditions that are particularly favourable for Dollar Spot disease include:
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Temperature range of 16°C to 28°C and continuous high humidity above 85%.
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Warm humid weather with cool nights that produce heavy dews.
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When the micro-climate temperature reaches 16°C the fungus resumes growth.
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Low nitrogen levels.
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More severe in dry soils.
What can I do to manage or control Dollar Spot Disease?
Recover from dollar severe cases of dollar spot can be extremely slow. To control and reduce instances of dollar spot, we recommend the following management practices:
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Preventative fungicide spray program.
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Provide adequate level of nitrogen, particularly in the spring and early summer.
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Mow grass at regular intervals.
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Reduce thatch.
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Increase the air circulation.
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Irrigate turf deeply and as infrequently as possible to avoid drought stress.
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Remove dew from the turf early in the day
