5 Common Fungi in Lawns and How to Treat Them


Maintaining a healthy lawn is a year-round endeavor that requires constant attention and care. This is particularly true in Florida, where the warm, humid subtropical climate makes it susceptible to fungal infections throughout the year. In addition to warm-season grasses like Zoysia grass, this unique condition provides an optimal environment for fungal diseases, like brown patch disease and leaf spot fungus.

How to Prevent Lawn Fungus

The first step to control fungus is identifying the type of lawn disease you're dealing with. With this knowledge, you can take appropriate precautions and employ targeted fungus control measures.

Good lawn care practices, such as watering early in the morning to allow it to dry throughout the day, are also key to keeping your lawn healthy and protecting it from lawn diseases. It prevents stagnant water that can create a conducive environment for fungal growth.

How you trim your lawn can make a difference, too. Ensure your mower blades are sharp to cut the grass blades cleanly instead of ripping them, making your lawn more susceptible to fungal diseases. Additionally, avoid leaving excessive grass clippings on the lawn. An inch-thick layer should be enough for mulching. Anything more than that can retain excessive moisture, potentially fostering diseases. Follow the one-third rule, ensuring you cut no more than one-third of the grass height in each session.

Effective lawn fungus treatment should also include proper fertilization, dethatching, and aeration to relieve compacted soil. These measures contribute to a well-balanced lawn that is more resilient against fungal infections.


5 Most Common Fungal Diseases in Florida

Below is a list of the most common lawn diseases Florida homeowners often encounter.

Brown Patch Lawn Disease

Brown patch is a prevalent disease in St. Augustine grass. Still, it can also affect other warm-season grass species like Bermuda grass. This fungal disease initially appears as yellow patches, progressing to brown or reddish-brown circular areas with a darker ring around the edges, eventually causing the leaves to wilt. Starting as small as a few inches, it can rapidly expand to several feet if not treated.

Triggered by rainfall, excessive irrigation, or prolonged high humidity, brown patch fungus develops when daytime temperatures exceed 85°F and evening temperatures are above 70°F. While symptoms may resemble herbicide damage, brown patch differs as the leaves may wilt, starting from the blades closest to the soil, but the roots remain intact.

Dollar Spot

Starting as a small circular spot, often the size of a silver dollar, this fungal infection is common in warm-season grasses and can kill grass right down the roots. It manifests with lesions on grass blades, transitioning from brown to white before eventual death.

Lack of nitrogen can contribute to this issue, emphasizing the importance of proper soil fertilization to prevent it. In severe cases, use lawn fungicides to keep it from spreading and taking over the entire lawn.

Leaf Spot Fungus

Gray leaf spots may resemble the initial stages of brown patch fungal disease. But they uniquely affect the top of the leaves, creating tiny circular or oval spots with gray spores in the center, giving them a velvety gray appearance.

Excessive moisture, compacted soil, poor air circulation, and overuse of nitrogen fertilizer can contribute to leaf spot fungus, reducing your lawn's ability to thrive and causing it to become sparse. Prevent gray leaf spots by removing dead grass through dethatching and mowing at the recommended height and only when the grass is dry.

Root Rot

Root rot is associated with consistently wet soil conditions attributed to poor drainage, excessive watering, and soil compaction. This leads to a decline in grass quality and density, causing the grass blades to wilt and eventually resulting in the death of your lawn.

Preventive measures like dethatching and aerating your lawn each spring can help prevent root rot. Monitor the rainfall your lawn receives and adjust your watering schedule accordingly to prevent overwatering, thus reducing the risk of root rot.

Fairy Rings

While the name may sound whimsical, Fairy Ring disease is a challenging issue as it tends to persist for several years before visible signs emerge, making it difficult to get rid of.

The disease spreads through the root system, forming small rings of initially dark green grass that later turn brown as the grass dies. Occasionally, small mushrooms may appear at the edges as the fungus takes its toll on the grass. A targeted fungicide treatment integrated with consistent lawn care practices is essential to address this disease and prevent recurrence.


Restore Lawn Health with Proper Maintenance and Grass Plugs

Proper lawn maintenance and effective fungus control go hand in hand in shielding your lawn from these common fungal diseases. Ensuring adequate watering, fertilizing, mowing, and constant monitoring can go a long way toward a greener and more resilient lawn. While fungicide application may be necessary, it's crucial to identify the specific fungi affecting your lawn for targeted treatment.

In cases of severe damage, you can rejuvenate your lawn by removing dead grass and strategically using grass plugs. Our SodPods grass plugs provide a practical solution, promoting a rapid and even lawn recovery after a disease. It works by introducing small, healthy grass plugs with established roots into damaged areas.

To plant grass plugs, dig a hole in the affected area, insert them, and water deeply and thoroughly for the next few weeks to facilitate their establishment into the existing lawn. Supplement your grass plugs with NutriPod, a slow-release grass plug fertilizer that provides a gradual and steady release of nutrients to boost root development, stimulate healthy growth, and restore your grass to perfect health, fostering a vibrant and resilient lawn for the long term.

Read here for a more comprehensive, step-by-step guide on how to start a lawn with grass plugs.

Jamie Tedder

Jamie surrently serve as Vice President on the board for Turfgrass Producers of Florida. He currently oversees the production of all grasses throughout all farms in Florida at Bethel Farms. He is actively working with top grass breeders, researchers, producers and end users from public and private institutions around the country to stay up to date on current industry developments. Being a University of Florida graduate, he has applied that knowledge to over 22 years of experience growing spectacular grass!

Leave a comment

Please note, comments must be approved before they are published