Rust
Causal Agent
Puccinnia & Uromyces specie
What is rust disease?
Rust is a fungal turfgrass disease that affects grasses growing under stressful environmental conditions. Rust can appear as yellow to reddish-brown in colour on affected turf, giving the disease its name.
What are the symptoms of rust disease?
Symptoms of rust disease include:
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Early symptoms of Rust diseases appear as light-yellow flecks on leaves or stems.
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The flecks enlarge, elongate, and turn yellow in colour.
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The yellowed area of the infected spots enlarge and elongate parallel to the leaf or stem axis as the infection matures.
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The leaf blade turns yellow starting at the tip and progressing to the base.
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A severe infection can cause the shoot to turn yellowish to reddish-brown and slow down growth.
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As individual plants die, the turf thins
What causes rust?
Rust is caused by Puccinnia & Uromyces fungal species. When grass is affected by rust, the infected areas rise above the epidermis and then rupture, releasing spores that are yellowish-orange to reddish-brown in colour.
What Turfgrasses are particularly susceptible to rust?
All cool season turfgrass species.
When does rust occur?
The conditions particularly favourable to rust include:
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Early spring through mid-summer.
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Rusts favour moist, low-light areas.
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Leaf wetness is required for fungal growth.
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Depending on the species, rusts favour temperatures between 18°C and 30°C.
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Severe Rust infections occur on slow-growing turfgrass particularly those with low nitrogen levels and/or plant water stress.
What can I do to manage or control rust disease?
Turf management practices that can help control or reduce instances of rust disease include:
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Convert to a turfgrass seed blend that is resistant to rust diseases found in the area.
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Apply adequate levels of nitrogen and other nutrients.
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Remove clippings from turf.
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Reduce shade and improve air circulation.
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Regulate irrigation to minimise the amount of time moisture remains on the leaf surface.
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Water deeply and infrequently