Brown Patch & Cool Season Lawns

By on August 1, 2015

Brown Patch & Cool Season Lawns

Landscape & Garden Editor Kevin Johnson Gives Us 
the Basics for Summer Lawn Care

Mr. Smith recently had his lawn sodded with a turf type fescue. The new sod was laid and it created the green space he was looking for. Having spent significant money he was diligent to do whatever it took to make sure the lawn would survive. He followed the landscaper’s watering instructions diligently, yet his lawn started turning brown. Naturally he increased the watering only to watch the majority of the sod die as the lawn appeared to dry out.

This scenario happens often. What happened to Mr. Smith’s lawn?

Rhizoctonia solani, otherwise known as Brown Patch is a fungal disease of cool season lawns. What Mr. Smith mistook as a dry lawn was actually Brown Patch, which only worsened with the additional irrigation. This particular disease generally occurs during periods of warm and humid weather and is the main disease we deal with in our fescue lawns. This disease is identified by browned out rings or patches ranging from a few inches in diameter to several feet. Sometimes with the onset of cool weather the disease can be grown out, often it can cause considerable damage.

There are several things a homeowner can do to help avoid damage caused by fungal diseases in fescue lawns. Here are a few recommendations.

  1. Avoid applying nitrogen to your lawn in the summer. Early spring and fall are the proper times for nitrogen applications. Summer nitrogen applications encourage disease.
  2. Mow the lawn high during the summer months. I recommend 4 inches or more. This not only keeps the pathogen from spreading to the crown as quickly which causes damage, it also help to shade and cool the root system at the same time reducing weed competition.
  3. Avoid night-time watering. If you’re fortunate enough to have an irrigation system set it to come on early in the morning, and when you have to water manually get out early. When the lawn stays wet through the night it promotes disease.
  4. Fescue lawns typically need 1 inch of water per week. If we’ve had rain, adjust your watering to accommodate the rainfall.
  5. Use fungicides. There are many good fungicides that can provide 14-28 day’s control of Brown Patch disease. It you want to keep your fescue healthy during the summer months a fungicide regimen is the way to go.

Fescue lawns are not the only turf types prone to disease. Bermuda grass and Zoysiagrass can also develop problems. A common disease of Bermuda grass is Dollar Spot and Zoysiagrass can develop Large Patch. These are the same pathogens that cause Brown Patch in Fescue.
Being familiar with the various turf disease will keep what happened to Mr. Smith’s lawn from happening to yours. ACLM

For additional reading on the subject visit:

Kevin Johnson is the owner of Green Leaf Lawn and Ornamental, LLC, based in Blue Ridge. For more information about the devastating hemlock woolly adelgid and treatment options, Kevin can 
be reached toll free at 866. 883. 2420 
or by email at 
Or check out his web site at or visit for more info