Dollar spot and brown patch are two common lawn diseases caused by invasive fungi. Due to these lawn diseases, the lawn can undergo extensive damage in a short period of time. Lawn diseases can be difficult to control unless people know how to identify lawn and grass diseases accurately.
The key difference between dollar spot and brown patch is their appearance. Dollar spots manifest as small silver dollars throughout the lawn while brown patch manifest as brownish-yellow patches throughout the lawn.
CONTENTS
1. Overview and Key Difference
2. What is Dollar Spot
3. What is Brown Patch
4. Similarities – Dollar Spot and Brown Patch
5. Dollar Spot vs Brown Patch in Tabular Form
6. Summary – Dollar Spot vs Brown Patch
7. FAQ – Dollar Spot and Brown Patch
What is Dollar Spot?
Dollar Spot is a lawn disease that can normally affect residential lawns. This lawn disease specifically affects cool season grasses like Kentucky bluegrass, perennial ryegrass, and fine fescue. The areas affected by this disease usually appears as straw or tan colored spots in the lawn. These spots are small, round, and the size of a silver dollar. Moreover, the spots may also have a reddish-brown border.
Figure 01: Dollar Spot
Dollar spot lawn disease is caused by the fungus Sclerotinia homoeocarpa. This fungus thrives in warm and humid conditions. Sclerotinia homoeocarpa spreads in grasshades through contact or through the air. Furthermore, dollar spot can be controlled by pruning overly shady grass plants and applying fungicides such as myclobutanil, propiconazole, or triadimefon.
What is Brown Patch?
Brown patch lawn disease appears during periods of hot and humid weather. It appears as a purple or grayish-brown cobwebs in the early morning dew, which looks like rough, circular patches, varying in size from few inches to several feet. Brown spots cause significant damage to grass plants such as tall fescue, perennial ryegrass, and creeping bentgrass, and less damage is done to Kentucky bluegrass.
Figure 02: Brown Patch
Brown patch is a lawn disease caused by the Rhizoctonia fungi. This fungus affects grass foliage and crowns. Rhizoctonia usually colonizes the organic matter in the thatch layer and infects it mainly during times of stressful conditions. This fungus affects cool season grasses and most likely to destruct grass plants when temperatures are above 85°F with high relative humidity. Furthermore, brown patch lawn disease can be controlled by improving soil drainage and applying fungicides such as azoxystrobin, pyraclostrobin, or fluoxastrobin.
Similarities Between Dollar Spot and Brown Patch
- Dollar spot and brown patch are two lawn diseases.
- Both diseases are caused by invasive fungi.
- They are developed in hot, humid environments.
- Both diseases predominantly affect cool grass plants.
- These diseases can cause extensive damage to grass plants like perennial ryegrass.
- They can be controlled by applying fungicides.
Difference Between Dollar Spot and Brown Patch
Definition
- Dollar spot fungal lawn disease appears as round and sunken spots, usually straw-colored or white, on the lawn.
- Brown spot fungal lawn disease appears as circular tan, brown, yellow, or orange patches on the lawn.
Causes
- Dollar spot is caused by Sclerotinia homoeocarpa.
- Brown spot is caused by Rhizoctonia solani fungi.
Effect on Grass Plants
- Dollar spots cause extensive damage to Kentucky bluegrass, perennial ryegrass, and fine fescue.
- Brown spots cause extensive damage to tall fescue, perennial ryegrass, and creeping bentgrass and less damage to Kentucky bluegrass.
Treatment
- Dollar spot can be treated by pruning overly shady grass plants and applying fungicides such as myclobutanil, propiconazole, or triadimefon.
- Brown spot can be treated by improving soil drainage and applying fungicides such as azoxystrobin, pyraclostrobin or fluoxastrobin.
The following table summarizes the difference between dollar spot and brown patch.
Summary – Dollar Spot vs Brown Patch
Dollar spot and brown patch are two lawn diseases that are caused by invasive fungi. Dollar spots appear as small silver circular dots slightly larger than a dollar coin, while brown patches appear as purplish green to brown circular patches, which can range in size from a few centimeters up to a meter in diameter. Furthermore, dollar spot is caused by the fungus Sclerotinia homoeocarpa, whereas brown patch is a lawn disease caused by the Rhizoctonia solanifungi. This is the summary of the difference between dollar spot and brown patch.
FAQ: Dollar Spot and Brown Patch
1. What does lawn disease look like?
- Most common lawn diseases are fungal infections. They appear as patches of discolored or dying grass, ranging in color from yellow to brown with circular or irregularly shaped spots on the lawn. Fuzzy, powdery, or slimy growth on the lawn may also develop.
2. What causes a dollar spot on the lawn?
- Dollar Spot disease is caused by a fungus called Sclerotinia homoeocarpa, and it is common in both warm and cool-season grasses across Australia, America, and other European countries. This fungus becomes active when conditions are warm, humid, and on cool nights, as well as when there are heavy dews.
3. What is the best treatment for a dollar spot?
- The best fungicide for dollar spot is chlorothalonil. It is said to be highly effective in controlling and preventing the spread of dollar spots throughout the lawn.
4. How to identify brown patch fungus?
- The first sign of brown spots is a circular or oblong pattern of light-yellow discoloration appearing on the lawn. One of the most frustrating aspects of brown patches is that they may spread from inches to a few meters.
5. What is the best fungicide for brown patches on the lawn?
- Compendium® is the best fungicide for preventive control of brown patches. It contains the active ingredients azoxystrobin and propiconazole, and it delivers broad-spectrum control of brown patch lawn disease.
Reference:
1. Burke, Kelly. “How to Get Rid of Brown Patch Grass Fungus.” The Spruce, The Spruce.
2. “Lawn Diseases.” Lawn Diseases | University of Maryland Extension.
Image Courtesy:
1. “Turf (Bermudagrass): Dollar spot, prob. caused by Sclerotinia homoeocarpa” By Scot Nelson (Public Domain) via Flickr
2. “Brown Patch” By Scot Nelson – (CC0) via Commons Wikimedia
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