Brown Patch Disease in Fescue Grass

Symptoms

• The exact coloration of the blades of grass distinguishes the disease from other causes of browning in a lawn. Under careful examination, you will notice the blades will be a lighter tan color on the insides, with a darker brown crusting the outsides of the blades. If the disease has not had a lot of time to spread, each blade of grass will have only small patches of brown on them; over time the brown spreads throughout the whole leaf. As the fungus spreads, the initially infected areas will tend to heal as the fungus works its way outwards, often creating a bulls-eye like appearance with healthy grass in the center surrounded by infected grass.

Causes

• Like most fungi, brown patch grows best in hot, moist conditions, so it tends to become prominent in the summer, when heat and humidity are high both day and night. High rainfall and dew will also lead to the development of the fungus, as the excess moisture sits on the blades of grass. Excessive nitrogen in the soil can also lead to this problem, as extra nitrogen produces young growth that is more susceptible to fungal infection.

Prevention

• Some types of fescue grass are more resistant to brown patch than others, so plant these if you know your area suffers from this disease. Fertilize the lawn in early spring with a slow-release fertilizer and do not feed again throughout the summer to prevent nitrogen buildup during the time the lawn is most susceptible. Water your lawn only in the early morning to allow excess moisture to evaporate during the day. Water deeply so the grass is uniformly moist.

Control

• The worst cases of the disease will require application of a fungicide. Chemicals such as propiconazole and triadimefon are available through garden centers and nurseries for homeowner use. Carefully follow all instructions for using these products, or you can severely harm the grass. If you are unsure about the condition of your lawn or how to apply fungicides, don't risk it; contact a professional at a garden center, nursery or extension service for help.