Rust

Hosts, Symptoms & Signs

• many types of grass are susceptible, including Kentucky bluegrass and perennial rye
• orange colored “dust” is seen on grass blades; the dust is orange spores that give the disease its name
• lawn that is stressed is more susceptible to the disease
• rust is more common in shaded and moist parts of the turf area

Disease Cycle

• spores are dispersed through air, mowing, shoes and animals
• the fungus is most active during temperatures of 70-85 degrees F

IPM Recommendations

• Rust is mainly a cosmetic problem. It will not kill the grass.
• Fertilize and irrigate as needed to avoid stress. Irrigate in the morning so the grass is dry overnight.
• Mow frequently and remove clippings to remove new infection early, but do not mow below the recommended height.
• Prune trees to increase light in heavily shaded areas and increase air movement to reduce humidity.
• Fungicides containing azoxystrobin can be applied but are often unnecessary.