Problem Management

Apply Lawn Fungicide to Tall Fescue in Summer

Written by Hillary Thompson | Jul 9, 2015 4:00:00 AM

Brown patch, caused by the Rhizoctonia species fungus, is the most common disease that can develop in a Fescue lawn. It appears as a brown or yellow circular patch of grass that can vary in size from a few inches to several feet in diameter.

Tall Fescue grass is more susceptible to brown patch during the hot, humid summer months.

Lawn fungicide or fungus control can be applied to the lawn after brown patch has appeared, but it is best to take preventative action and begin applying fungus control for the duration of the summer months.

We recommend beginning lawn fungicide applications when nighttime low temperatures rise to 60°F. Typically, preventative applications are made at 14 to 30 day intervals, depending upon the fungicide.

There are an abundance of lawn fungicides available that prevent brown patch and other lawn diseases. Our stores carry Strobe Pro G because it's the best lawn fungicide on the market offering 2 modes of action and it's longer lasting on the lawn once applied.


Following good lawn care habits will also help prevent diseases.

We recommend applying Strobe Pro G once a month during summer, coupled with these five preventative cultural practices, to help you care for your Tall Fescue lawn like a pro.

  • Avoid over watering by irrigating only when there has not been sufficient rainfall. An established fescue lawn needs 1" of water per week during the cool months; up to 2" per week during the warm months.
  • Water your lawn in the morning: This timeframe is to allow moisture to more rapidly dry off the leaf blades during the day, rather than watering in the evenings when moisture will not rapidly dry, instead it will remain on the leaf blades overnight. Watering in the evenings promotes diseases.
  • Raise your mower height: If you cut it at 2.5-3" over the winter, raise it to 3-3.5" for the warm months. Also, never cut more than 1/3 of the blade height at each mowing.
  • Do not fertilize tall fescue grass during the warm months: fertilize only when this type of lawn, classified as a "cool-season grass," is actively growing during the cool months of early spring and late fall. However, it's still okay to apply lime to neutralize the pH of your soil. Always take a soil test to confirm if you need to apply lime or fertilizer.
  • Topdressing in the autumn with compost is a sound organic fertilization practice that not only improves the quality of your soil and adds natural nutrients, it also provides good types of bacteria to the lawn that may out compete disease-causing pathogens.