Rust
Puccinia spp.
Foliar rust fungi producing orange-yellow pustules that rub off as powder onto shoes and equipment.
Identification
Yellow-orange flecks that develop into raised pustules releasing orange spores. Heavily infected turf looks yellow-orange and thin; spores coat shoes and mowers.
Symptoms
The symptoms of rust can vary depending on the species of Puccinia and the host grass. In general, rust causes yellow or orange pustules on the leaf blades of the grass. These pustules can cause the leaves to become distorted and/or stunted. In severe cases, rust can cause significant thinning of the turf.
Signs
The most obvious sign of rust is the presence of the orange or yellow pustules on the leaf blades. These pustules will release spores when they rupture, which can be observed with a microscope.
Biology
Rust is caused by various species of the fungus Puccinia. The fungus infects the leaves of the grass, causing yellow or orange pustules (uredia) on the leaf surface. It is considered a secondary pathogen, meaning it requires a weakened host to establish infection.
Epidemiology
Rust is most common in the summer months and is favored by warm, humid weather. It is typically more severe in the southern regions of the United States but can occur anywhere that cool-season grasses are grown.
Favorable Conditions
Slow growth from low fertility, drought, or shade in late summer; heavy dew.
Cultural Management
To manage rust, it is important to maintain a healthy, vigorous turf. This includes proper fertilization, irrigation, and mowing practices. Avoiding high rates of nitrogen, especially quick release, and mowing at the appropriate height for the species will help to keep the grass healthy and more resistant to infection. It is also important to limit stress on the turf by avoiding heavy traffic and other stresses.
Further Reading
University extension resources — open in a new tab.
Related Reports
No published reports yet for this pest.
Reports will appear here as they are peer-reviewed and published.