Why Does Fescue Grass Turn Yellow?
Fescue (Festuca spp.) is a cool-season grass well adapted to growing in cooler regions. The low-maintenance grass has low water and fertilizer requirements. Fescue is susceptible to a fungal disease that gives the grass a yellow look.
Rust is a fungal disease caused by Puccinia spp. The disease is most common on tall fescue grass. Rust fungi are prevalent in hot weather when grass growth rate is slower.
The disease starts with the appearance of long, yellow-orange pustules on grass blades. These pustules are filled with fungal spores that are released in the form of orangish powder when the grass is cut. As disease progresses, the blades turn entirely yellow and start to die. Rust-infected lawns take on an overall yellow appearance.
Keeping lawns in vigorous health with proper watering and fertilization is among the best defense strategies as the disease favors weak and poorly growing grass. Mow lawn frequently and remove all clippings. Fungicides are not generally recommended for rust control.