Garden Column for the Salisbury Post
Darrell Blackwelder
June 30, 2003

    You would think with all the rain over the past few months our lawns would look great. However, once the sun finally arrived many have discovered serious problems with their lawns. Large brown circles or brown patch has hit cool season fescue lawns in our area with a vengeance.
    Brown patch is caused by a soil borne fungus Rhizoctonia solani. It is by far the most common disease of tall fescue. Recent weather patterns with several days of rain and heavy cloud cover along with day temperatures above 80 degrees F are perfect conditions the disease. Early symptoms of this disease are small circular brown patches of turf a foot in diameter. Small patches often melt together and may engulf an entire lawn.
    Vigorously growing turf fertilized with high rates of nitrogen fertilizer during late spring or the summer is very 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 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 very susceptible to brown patch.
    Over-seed with different cultivars of fescue to avoid rapid spread of the disease. Monocultures of fescue cultivars can be completely engulfed by the fungus. Damaged lawns will need renovating in the fall to correct soil pH and fertility problems and reseeding in September. Now is the time to have soils tested for fall renovation.
Established lawns may be damaged during the summer months, but with proper maintenance will recover during the fall. Maintaining proper nutrition is important. Soils must have proper soil pH to achieve maximum growth. Avoid using high nitrogen fertilization levels during late spring and summer.
    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 or phone at 704-633-0571.