Rust

Causal Agent: Puccinnia & Uromyces specie

Susceptible Turfgrasses: All cool season turfgrass species.

Symptoms

  • Early symptoms of Rust diseases appear as light-yellow flecks on leaves or stems.

  • The flecks enlarge, elongate, and turn yellow in colour.

  • The yellowed area of the infected spots enlarge and elongate parallel to the leaf or stem axis as the infection matures.

  • The leaf blade turns yellow starting at the tip and progressing to the base.

  • The infected areas rise above the epidermis and then rupture, releasing spores that are yellowish-orange to reddish-brown in colour.

  • A severe disease infection can cause the shoot to turn yellowish to reddish-brown in colour and slow in growth.

  • As individual plants die, the turf thins

Conditions Favouring Disease

  • Rust diseases typically occur in early spring through mid-summer.

  • Rusts favour moist, low-light areas.

  • Leaf wetness is required for fungal growth.

  • Depending on the species, rusts favour temperatures between 18°C and 30°C.

  • Severe Rust infections occur on slow-growing turfgrass particularly those with low nitrogen levels and/or plant water stress.

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