Fescue Sod Is Turning Black

Stripe Smut

• Stripe smut primarily infects cool season grass types such as fescue, according to the University of California. Gardeners may see signs of the disease when the weather cools between 50 to 60 degrees Fahrenheit in the spring or in the fall months, according to North Dakota State University. Symptoms of stripe smut rarely occur in the summer when temperatures soar past 90 degrees Fahrenheit. The disease is caused by Ustilago striiformis fungal spores, which can wreck havoc on fescue sod.

Symptoms

• Gardeners may see their fescue sod grass blades display long, yellow-greenish streaks, according to North Dakota State University. As the disease progresses, these streaks turn black. These black areas burst with fungal spores that go on and infect other areas of the fescue lawn. The blades eventually turn downward. Fescue lawns that have been infected with stripe smut exhibit bare patches and thinning grass. Gardeners can use both cultural and chemical treatment practices to control the spread of the disease.

Treatment

• Avoid using excessive amounts of nitrogen in the summer, as suggested by the University of California. Fescue sod that has contracted with stripe smut is already stressed from the disease. Fertilizer encourages new growth, which puts additional stress on the grass blades. Treat severely infected fescue sod with a fungicide that contains mancozeb, captan or mycolobutanil, as recommended by the University of California. Refrain from treating fescue sod with the fungicide if the grass appears water stressed.

Slime Mold

• Fescue sod that has contracted slime mold looks as though someone has poured oil over your grass. Gardeners may see the fungal disease turn gray before turning dark black. Different from stripe smut, this fungal disease doesn't attack your fescue sod. Gardeners can wash off their fescue sod in the early morning to remove the fungal spores. Avoid washing off the sod late in the day, or you can encourage other fungal diseases.