We receive quite a few tall fescue disease samples during the spring and summer months in the Plant Disease and Homeowner IPM Clinics. The majority are diagnosed with Brown Patch caused by the fungus Rhizoctonia solani . Early symptoms of the disease are small, circular brown patches 6 to 12 inches in diameter. Other patches develop and older patches may continue to enlarge during hot, dry and wet weather. If the turf is not irrigated, tall fescue lawns near the end of the summer may have a uniform brown appearance without patches.
Tall fescue is a cool season grass and is stressed by our summer conditions and periods of drought.
There are, however, management practices that can help reduce stress to the grass and aid in disease control. Lush, vigorously growing plants that have received high nitrogen during the spring and summer are very susceptible to brown patch. The proper time to fertilize tall fescue is during the fall and winter months. Soil test prior to fertilizing in the fall and adjust these levels accordingly. If establishing a tall fescue lawn, the best time to do so is in September or October.