The last couple of months my lawn has been perfect. All the rain and cool weather was perfect growing conditions for fescue. Unfortunately, once the high temperatures of summer finally arrived I, like many others, have discovered serious problems with lawns. Large brown circles have tainted cool season fescue lawns in our area with a vengeance. Brown patch is here.
    Brown patch is a common turf disease caused by a soil borne fungus Rhizoctonia solani. Recent weather patterns of rain and heavy cloud cover along with increasing temperatures above 80 degrees F are perfect conditions for this disease. Early symptoms are small circular brown patches of turf a foot in diameter. Small patches often melt together and may engulf an entire lawn.
    Turf fertilized with high rates of nitrogen fertilizer during late spring or early summer makes lush fescue susceptible to the disease. Tall fescue grown in partially shaded lawns and where air movement is restricted is more susceptible to brown patch because of higher humidity and more succulent growth.
     Fescue lawns established less than one year can be severely damaged or completely eliminated by this disease. Seeding rates of more than 6 pounds of seeds per 1,000 square foot, produces small, crowded seedlings with poor root systems that are also susceptible to brown patch.
   Over-seeding with different fescue cultivars helps reduce the rapid spread of the disease. Monocultures of fescue cultivars can be completely engulfed by the fungus.

     Brown patch infested lawns may need soil tested to determine if low pH is a contributing factor. A pH below 6.0 aggravates the spread of brown patch. Now is the time to have soils tested if fall renovation is in your plans. Soils must have a proper soil pH of 6.0-6.5 to achieve maximum health and growth to ward off the fungus. Turf and ornamental fungicides such as Banner, Bayleton, Eagle and Heritage can be applied as a control for brown patch. However, these may require repeated applications and can be rather pricey.
     According to plant pathologists at N. C. State University, the most important step of controlling brown patch is infrequent irrigation and regular mowing when the grass is dry. Unusually cool, wet weather over the past few weeks has made this almost impossibility, hence the rapid outbreak of the disease. Avoid irrigation in the late evening or at night. Early morning irrigation helps prevent the spread of brown patch.

Darrell Blackwelder is an agricultural agent in charge of horticulture with the North Carolina Cooperative Extension Service in Rowan County. For archived garden columns or other information, visit the Rowan County Master Gardener web site at www.rowanmastergardener.com, e-mail Darrell_Blackwelder@ncsu.edu