What is Dollar Spot and how can you treat it?

The Lowdown on Dollar Spot: Causes, Symptoms, and Treatment Methods

The million-dollar question: What is Dollar Spot and how can you treat it?

Dollar spot, a common and destructive turfgrass disease, is a challenge for gardeners and turf managers alike. Understanding what it is, recognising its warning signs, and knowing how to prevent and treat it is essential for maintaining healthy and aesthetically pleasing lawns.

Here’s a brief guide to all things Dollar Spot!

What is dollar spot?

It’s caused by the fungal pathogen Clarireedia jacksonii (formerly known as Sclerotinia homoeocarpa), primarily affects cool-season grasses such as bentgrass, bluegrass, fescues, and ryegrass. The name “dollar spot” derives from the small, silver-dollar-sized patches it creates on lawns, typically ranging from 2 to 6 inches in diameter. These patches can coalesce, forming larger areas of damaged turf if left untreated.

Warning signs of dollar spot

Recognising the early signs of dollar spot is crucial for timely intervention. Here are the primary indicators:

Small, circular patches: The most characteristic symptom is the appearance of small, circular, straw-coloured patches on the lawn. These patches are often about the size of a silver dollar, hence the name.

Hourglass-shaped lesions: On closer inspection, individual grass blades within the affected patches will exhibit distinctive lesions. These are typically tan-coloured with reddish-brown borders and often have an hourglass or elongated shape.

Mycelium: In the early morning when dew is present, you may notice a white, cobweb-like fungal growth (mycelium) on the grass surface. This is more evident during periods of high humidity and can be an early sign of infection.

Thinning turf: Over time, the patches may coalesce, leading to larger areas of thinning turf. This can severely impact the aesthetic and functional quality of the lawn if not managed promptly.

Prevention 

Preventing it involves implementing sound cultural practices that create an environment less conducive to the fungus. Here are some effective strategies:

Adequate fertilisation: Maintain balanced nitrogen levels. Dollar spot thrives in nitrogen-deficient soils, so a regular fertilisation program tailored to the specific needs of your turf species is essential.

Proper mowing: Mow the grass at the recommended height for the species you are growing. Avoid mowing too low, as this stresses the turf and makes it more susceptible to disease.

Watering practices: Water deeply but infrequently to encourage deep root growth. Avoid excessive moisture on the grass blades by watering early in the day, allowing the turf to dry before nightfall.

Thatch management: Excessive thatch provides a conducive environment for dollar spot. Regularly dethatching and aerating the lawn helps reduce thatch build-up and improves air circulation and water penetration.

Enhanced airflow: Improve air circulation around the turf by trimming nearby shrubs and trees. This reduces humidity levels, making the environment less favourable for fungal dollar spot growth.

Treatment 

If dollar spot does appear, prompt treatment can help mitigate its impact. Here are the key treatment options:

Fungicide application: Fungicides are a primary tool for controlling dollar spot. Select a fungicide labelled for dollar spot and follow the manufacturer’s recommendations for application rates and timing. Rotate fungicides with different modes of action to prevent the development of resistance.

Reseeding and overseeding: In areas where the turf has been severely damaged, reseeding or overseeding with disease-resistant grass varieties can help restore the lawn’s health and appearance.

Professional help: For severe or persistent cases, consulting a turf management professional can provide specialised expertise and treatment plans tailored to the specific conditions of your lawn.

Dollar spot is a prevalent and potentially damaging turf disease that requires vigilant monitoring and proactive management. By understanding its warning signs and implementing both preventive and treatment strategies, you can maintain healthy, disease-free turf in your clients’ gardens. A proactive approach not only enhances the beauty of the lawn but also ensures its resilience against future outbreaks.

We are always happy to discuss all things turf – call us for help with any troubleshooting or products to assist you!