Rust (fungus – Puccinia cynodontis)
Host Grass: Common Bermuda, Perennial Ryegrass(Lolium perenne), Poa Series(Poa sp.), St. Augustine Grass(Stenatophrum secundatum), Zoysiagrass(Zoysia japonica)
Cause and Symptoms: Bluegrass, ryegrass and zoysiagrass are most commonly affected. Rust diseases are favored by warm humid conditions and develop most frequently on grasses stressed by drought conditions, low nitrogen fertility and shade. Disease first appears on leaves as small orange to reddish-brown flecks that enlarge to form raised pustules. Individual pustules are usually oval or elongated and contain a powdery mass of orange to reddish-brown spores. As pustules mature, they turn brown to black. Heavily infested turf becomes thin with an overall yellow-orange to reddish-brown color. Infected leaves turn yellow, wither and die.
Control and Management: Maintain adequate nitrogen levels, avoid moisture stress or overwatering and adjust mowing heights according to turf requirements. Use rust resistant varieties. Fungicides (See the section Chemical Controls for Turfgrass Diseases) are available for rust control.
Content edited by: Young-ki Jo, firstname.lastname@example.org , Assistant Professor and Extension Specialist, Dept Plant Pathology & Microbiology, Texas A&M University, Texas AgriLife Extension Service, May 31, 2013