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Brown Patch Lawn Disease: Identification & Treatment

A lawn suffering from brown patch fungus damage

Your lawn is the first impression your home makes, which is why it can be so frustrating when patches of brown creep in. While brown patches may look like pockets of dead grass (and they sometimes are), generally the cause is an actual fungus called Brown Patch (Rhizoctonia solani). Here is a little more information about this stubborn and annoying turfgrass disease.

What is Brown Patch?

Brown patch is a very common turfgrass disease that can be found in many warm-season turfgrasses throughout the United States, especially Zoysia and St. Augustine. The disease is foliar, meaning that it does not affect the crown or roots of the grass, just the blades.

First, small circular patches begin to appear—but within a matter of weeks, the circle's diameter rapidly grows from 10 to 12 inches to several feet. Blades of the grass can be easily separated from the stolons of the grass, with a rotted appearance at the base of the detached leaves.

What causes Brown Patch?

Brown patch fungus commonly develops when night-time temperatures are 70 degrees F and below and are often caused by a combination of the following factors:

  • Cooler night-time temperatures
  • Excessive moisture
  • Poor drainage
  • Soil with high clay content
  • Shade
  • Mowing on too high of a setting.

How to Prevent Brown Patch Fungus

An ounce of prevention is worth a pound of cure, as the saying goes. While nothing will for sure prevent brown patch fungus from getting to your lawn, the following tips can reduce the chances.

  • Make sure to follow the appropriate lawn care tips, especially if you have a St. Augustine or Zoysia lawn. Watering should be done deeply and infrequently in the morning hours to prevent fungus growth. Learn more in our Watering Guidelines.
  • Mow the lawn frequently at a moderate height to improve air movement between the blades of grass. This will help evaporate any moisture on the grass, inhibiting the growth of brown patch fungus.
  • Proper fertilization ensures that your grass’ immune system has the nutrients it needs to fight off brown patch fungus.
  • Avoid using too much nitrogen during the fall, especially in a fast-release form, as it encourages fungus growth as well.
  • Water early in the morning so that everything evaporates from the grass leaves at night, leaving no water for fungus to grow.
  • Use preventative fungicides in September and October to drastically reduce the chances of brown patch fungus growing. However, directions need to be followed specifically to ensure the health of the grass.

How to Treat Brown Patch Fungus

We highly recommend the use of preventative fungicides, although the timing is as critical as the choice in fungicides.

If you already have symptoms of brown patch, we can still help stop it in its tracks. Our professional lawn care team has the knowledge and experience not just to get rid of that pesky brown patch fungus, but to help your whole lawn flourish. For more information on our lawn care services, please do not hesitate to give us a call. We’ll be happy to answer any questions you may have.