Click Images to Enlarge

Brown patch is most severe during extended periods of hot, humid weather. The disease can begin to develop when night temperatures exceed 60°F, but is most severe when low and high temperatures are above 70°F and 90°F, respectively. Brown patch also requires at least 10 to 12 hours of continuous leaf wetness in order to develop.

How to manage it

• Avoid excess nitrogen. Tall fescue should not receive more than 1 pound of nitrogen per 1,000 square feet at any one time.
• Avoid applying nitrogen in late spring or summer, or use very low rates (0.25 lb N/1000 ft² or less) if necessary.
• Ensure adequate amounts of potassium and phosphorus by applying these nutrients based on soil test results.
• Avoid prolonged periods of leaf wetness. To minimize leaf wetness, do not irrigate daily.
• Irrigation should be applied based on weather conditions and the water requirements of the turf.  The Turf Irrigation Management System is available as a guide to irrigation scheduling.
• It is best to irrigate early in the morning, just before sunrise. Avoid watering after sunrise or in the late afternoon or evening, as this will increase the duration of leaf wetness.
• Turf surrounded by trees, shrubs, or buildings will remain wet for extended periods of time due to reduced air movement and sunlight. Removal or pruning of trees will help minimize leaf wetness and discourage brown patch development.

Pesticide selection

Fungicides which contain one or more of the following active ingredients will provide good to excellent control depending on severity of the disease:

chlorothalonil

myclobutanil

For more information on Brown Patch and fungicide selection go to:

http://www.turffiles.ncsu.edu/Diseases/Default.aspx#IS004047

or

http://www.cals.ncsu.edu/plantpath/extension/fact_sheets/Turfgrass_-_Managing_Diseases_of_Tall_Fescue.htm