Rust on Turfgrass
David Pfeiffer, Eric Radachi, Joseph W. Rimelspach
Department of Plant Pathology
The Ohio State University
Rust is a common fungal disease found on most species of grasses around World. Rust can be found early spring through fall depending on the location. Yellow flecks on the leaf blades are the first signs of rust disease on turfgrass. The yellow flecks enlarge which cause the leaf epidermis to rupture and release yellow-orange powdery spores. These fungal spores easily get on shoes, mowers, and pets but are not harmful to humans or animals. In severe incidences, infected grass can thin and individual shoots may die.
- Perennial Ryegrass (Most Common)
- Kentucky Bluegrass
- Tall & Fine Fescues
Rust is favorable in slightly warm moist conditions in conjunction with prolonged leaf wetness from dew. Wetness of the leaf blade for more than 10 hours with air temperatures between 68° and 86°F, are optimum growing conditions for this pathogen.
- Mid-Summer through Fall (Most Common)
- Optimum air temperature for pathogen 68-86 F
- Leaf wetness followed by rapid increase in temperature and high light intensity
Stressed grass from:
- Low nitrogen
- Low mowing height
There are many types of fungi that cause rust. The most common are Puccinia graminis (Black Stem Rust), Puccinia coronate (Crown Rust), Uromyces dactylidis ( Leaf Rust), and Puccinnia striiformis (Yellow Stripe Rust). The disease life cycle of rust is often very complex.
Genetic host resistance:
Today there are many new cultivars that have a high resistance to rust diseases. It is important before seeding to make sure you select a resistant cultivar. Visit the National Turfgrass Evaluation Program (NTEP) at www.ntep.com to find more information on rust resistant turf.
The most effective control for preventing rust is to establishing a healthy turf. Providing enough nitrogen and maintaining a proper irrigation regime will minimize the chance of rust. Below are key cultural practices to prevent this disease.
- Maintain a good fertility program adequate for healthy turf growth
- Avoid moisture stress
- Avoid irrigating in evenings
- Raise height of cut
- Manage Soil to avoid compaction
Fungicides are commonly not used to control this disease if proper plant health practices are being done. However, if a severe rust outbreak exists on a healthy turf stand, two fungicide families, DMIs and Strobilurins, are the most effective in suppressing the disease. Remember to follow application rates and make sure the fungicide is labeled for your area of application (i.e. residential lawn or golf course). Below are a few of the effective fungicides for rust. Post infection applications often are slow to reduce the disease and multiple application may be required. Preventative applications are much more effective.
- Clarke, Bruce, Dernoeden, Peter, and Smiley, Richard. Compendium of Turfgrass Diseases.3rd. St. Paul, MN: The American Phytopathological Society, 2007. Print. Pg. 43-44
- "Rust on Turfgrass Factsheet." Plant Disease Dianostic Clinic, Dr. Eric B. Nelson. May 2009 <http://plantclinic.cornell.edu/FactSheets/turfrust/rust.htm>
- “Leaf Rust.” Turfgrass Disease Profiles, Richard Latin. Purdue University. May 2009 http://www.ag.purdue.edu/btny/extension/pages/extpubs.aspx
- Cornell University turfgrass extension website