Cool Weather Brown Patch Fungus“What is this weird brown circle in my lawn that seems to grow?? I’m watering… mowing… I’ve fertilized… HELP!!”

More than likely, especially if it’s around October – November when this problem is occurring, you more than likely have a fungal disease called “Cool Weather Brown Patch Fungus.” Fall’s cooler weather means Brown Patch will become more prevalent in North Central Florida lawns as our Pest Specialists have already encountered many cases of it this year.

Cool Weather Brown Patch Fungus is a broad term that classifies a range of fungi that affect warm weather grasses when evening temperatures are below 70 degrees. It is essentially a cool weather disease that will return each Spring and Fall if left untreated.

“Brown patch is strictly a cool weather season problem.”


Cool Weather Brown Patch starts as small, irregular patches or rings of dead grass that steady grow as time progresses – generally range from 1’ to 50’ in diameter.

Detection: look at a single grass blade that is starting to yellow on the outer edge of the grass patch. If the tip of the grass blade is turning brown and curling while the base of the blade remains green, there is a fungal disease present.

Favoring habitats

Most affected types of turf grasses are St. Augustine, Bermuda and Zoysiagrass. Heavily watered and overly fertilized lawns are more at risk to develop CWBP than other lawns.

Florida turf grasses take a tremendous beating over the summer from outdoor festivities and foot traffic to dry weather and wet weather to chinch bugs and other lawn pests. Then, when evening temperatures remain below 70 degrees for more than a couple of days – creates the ideal habitat for this fungal disease to become a problem for your lawn.

Other notes

Other lawn pests such as winter weeds will be more likely to take up space in your lawn if CWBP isn’t treated. It will return year after year and you will begin to see other seasonal insect damage such as Chinch bug, grub worm and destructive lawn pests.

Raise the mowing height for affected lawns by 1” to 2”. Always wash mower blades and mower well after each cut to prevent further spread of the disease.


The best course of action against Cool Weather Brown Patch Fungus is by giving our highly trained Lawn Pest Specialists a call. They will come out, assess the problem and will set the appropriate course of action. Call today at (386) 362-3887 for more information and to schedule an appointment.

Also see: Large Patch Grass Fungus

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