Dollar Spot Fungus is a common lawn disease caused by the fungus Sclerotinia homoeocarpa. It’s named after the small, round spots it creates on the grass blades that are the size of silver dollars. These spots are often straw-colored with a reddish-brown border and can quickly merge to form large patches.
Dollar spot is one of the most common fungal infections that affect lawns. If left untreated, it can cause significant damage to your lawn, leaving you with unsightly patches of dead grass. Fortunately, there are several steps you can take to prevent and treat dollar spots.
Causes of Dollar Spot Fungus
This is a fungal infection caused by a lack of moisture and humidity in the grass. Over-fertilization or under-fertilization can also contribute to the development of dollar spots. Mowing too short or infrequently can reduce the plant’s ability to resist disease, while soil compaction and poor drainage can create the ideal conditions for fungal growth.
Dollar Spot thrives in warm, humid weather, and is most common in lawns with low nitrogen levels and high moisture content. Overwatering, poor soil drainage, and compacted soil can all contribute to the development of the disease. Additionally, mowing the lawn too short or using dull mower blades can increase the severity of the disease.
Symptoms of Dollar Spot Fungus
The symptoms of dollar spot are easy to spot. You may notice small, circular patches of dead grass, along with gray or tan lesions on the blades of grass. The grass blades may also have a “bleached” appearance, and these patches may merge to form larger areas of dead grass.
These spots can be as small as a few inches or merge to form large patches up to several feet in diameter. The infected grass blades may have a straw-colored or bleached appearance, and the disease often causes the grass to thin out.
Prevention and Treatment
1. Lawn Maintenance Practices
The best way to prevent Dollar Spot is by maintaining a healthy lawn. This includes proper watering and fertilization, as well as regular mowing at the correct height. It’s recommended to mow the lawn to a height of 2.5 to 3.5 inches, as shorter grass is more susceptible to the disease.
Fungicides can be used to control and prevent Dollar Spot. They should be applied at the first sign of the disease and according to the manufacturer’s instructions. Fungicides containing active ingredients such as azoxystrobin, flutolanil, and propiconazole are effective against Dollar Spot.
3. Proper Watering and Drainage
Overwatering and poor soil drainage can increase the risk of Dollar Spot. It’s important to water the lawn deeply but infrequently, ensuring that the soil has a chance to dry out between watering sessions. Additionally, proper soil drainage can be improved by aerating the soil or using soil amendments.
4. Reseeding and Fertilization
If Dollar Spot has caused severe damage to the lawn, reseeding may be necessary. Choose grass varieties that are resistant to disease and fertilize the lawn appropriately to maintain a healthy and resilient lawn.
Dollar spot is a common problem for lawn care, but with the right preventative measures, you can keep your lawn healthy and free from fungal infections. By following the lawn care tips outlined above, you can help prevent dollar spot from taking hold in your lawn and keep it looking its best all year round.
Remember, a healthy lawn is the best defense against fungal infections like dollar spot.