"Stem and stripe" rusts are fungal diseases of grasses caused by the fungus Puccinia spp. "Leaf" rust on turf is a fungal disease caused by Uromyces spp. Early on, light yellow flecks or spots appear on the leaves and stems. After a short period of time, these spots become covered with rust-colored spore masses called pustules. Later, the pustules may turn yellow, orange, brown and eventually black. Severe infestations will deform, causing yellow leaves and leaf death. Rust does not usually hurt the grass, but under heavy infestation, the turf may wither and die due to heavy loss of moisture from rust-covered leaves. It is common when grass stays moist from irrigation or dew.
- Maintain healthy, vigorous turf.
- Increase nitrogen fertilization and mow frequently.
- Mow frequently
- Water early in the morning so grass dries by night.