How to Identify and Treat Lawn Fungus

Lawn Fungus

Identify and Treat Lawn Fungus

It’s August and summer here in Florida is in full swing. Temps are high and precipitation is plentiful, so it’s time for homeowners to be on the lookout for lawn fungi, which thrive in these warm, wet conditions. This is especially important to consider for homeowners who want to lay new sod, since they’ll want to wait until temperatures are lower and rainfall is less frequent. Here at Council Growers Sod of Hillsborough County, we recommend waiting until October to lay new sod here in Tampa Bay, as it is still warm enough for root establishment without being too wet. If you have any questions about laying new sod, contact us at (813) 633-8665.

In this post, we’ll cover how to identify and treat the most common fungal issues for Florida lawns.


Brown Patch

The brown patch starts in a small area but quickly grows to patches up to a few feet in diameter. Patches begin as small, tan-colored spots with dark brown borders on the grass blades and grow into larger areas of brown or dead grass circled with a dark brown, narrow ring. Some people report rings of yellow-brown grass with healthy grass both inside and outside the rings.

Fairy Rings

Fairy rings get their name due to the mushrooms that sometimes line the rings (the perfect size for an actual fairy to rest on), along with a quirky folk tale about the namesake fairies dancing in circles. However, dealing with fairy rings is a little less whimsical. These rings are dark green or brown and range from three to 20 feet in diameter. They are pervasive and will return to the same areas year after year. Fairy rings are very difficult to fully eradicate.

Dollar Spot

If you’re seeing brown circles about the size of a silver dollar along with tan spots with reddish borders on the grass blades, you’re probably dealing with dollar spot fungus. Those small brown circles quickly merge into one large area of dead, straw-like grass.

Gray Leaf Spot

Gray leaf spot looks a lot like brown patch fungus, with a few small but significant differences. First, the top of the grass leaves will show oblong dark green or brown spots that sometimes include a small bit of gray fuzzy material in the middle. Suspect gray leaf spots in times of heavy rain or prolonged high humidity.


If your lawn looks like it’s covered in a yellow, orange, red, or brown powder, rust fungus may be the culprit. Rust fungus will turn the glass blades shades of yellow and then dark red as it slows your entire lawn’s growth. Rust fungus isn’t usually what actually kills your grass, but it makes your lawn much more vulnerable to picking up other diseases.

Take-All Root Rot

Take-all root rot is caused by fungus and can quickly decimate an entire lawn. Yellowish patches that wilt away and turn brown are signs of this disease. These patches can be small or quite large, ranging from one foot to up to 20 feet in diameter.

Treatment of Lawn Fungus

Prevention is always the best way to deal with fungus, since, by the time you see the signs of it, it’s usually too late to save the affected areas. Sometimes, it’s too late to keep the entire lawn. If you see signs of fungal growth in your lawn, contact a lawn care expert immediately to find out your options. If you prefer the DIY route, a trip to your local lawn care store should give you some ideas.