Rust
Small, yellow flecks appear on affected leaves
Photo courtesy of Kansas State University
Rust is caused by the fungi Puccinia sp. and Uromyces sp.. All cool-season grasses can be affected, especially perennial ryegrass and certain cultivars of Kentucky blue grass. Zoysia grass can also be affected. Disease can occur from late spring through late summer.
Signs and Symptoms
Rust first appears as small, yellow flecks on the leaves. These flecks enlarge to form rust-colored pustules. Overall turf color may be yellow-orange to reddish brown. The affected turf yellows, withers and dies.
Favorable Conditions:
Moderately warm and humid conditions favor disease occurrence. Stressed turf is most susceptible.
Cultural Prevention and Control
Selecting rust resistant cultivars and maintaining adequate fertility levels may prevent disease occurrence.