June is in full swing and so is brown patch in tall fescue lawns and landscapes. Brown patch, caused by the fungus Rhizoctonia solani, is the most common disease in tall fescue during late spring and throughout the summer months in North Carolina. Brown patch infections can start as early as April in some years with full blown outbreaks occurring by late May and early June in most years. As the name implies, symptoms are brown to tan areas of turf that are roughly circular patches that range from a few inches to several feet in diameter.
The two most common mistakes managers of tall fescue make are fertilizing too late or too much in late spring and over watering. Tall fescue should not be fertilized after the first of May, unless you are using ultra low rates (< 0.25 lb N/M) with iron for a color effect. The recommended amount of nitrogen on tall fescue per year is 3-4 pounds per 1,000 square feet. Most people will apply a pound or two in the fall and a pound or two in the spring. When in doubt, submit a soil test to ensure you’re feeding your lawn the right nutrients at the correct amounts.
Watering should be done only as needed to prevent drought stress. When you do apply irrigation, do it deep and infrequent instead of watering every day. It is a common mistake for homeowners to set their irrigation system on a schedule and forget about it. Remember, fungi love water and if you over water, you're giving the advantage to the fungi, not the turfgrass. The ideal time to water your lawn is in the early morning hours before sunrise. Irrigating during late afternoon or early evening is the worst thing you can do because this extends the leaf wetness period, however brown patch will love you for it!