Lawn Diseases

Most widespread lawn diseases and measures to limit them

Pink Snow Mold (Monographella nivalis)

Pink snow mold (Fusarium nivale)

Grass begins dying in a round, elliptical, or irregularly shaped area. Grass blades are covered with a mycelium fungus off-white or pinkish in colour. The disease mainly manifests itself after the fall of snow. It is primarily caused by the failure to clean up and remove organic matter, snow on unfrozen ground, solidified surface soil, and an overabundance of nitrogen in the autumn. The affliction is stronger in shady places. The lawn takes on a brownish to brown colour and regenerates very slowly.

Countermeasures: Thoroughly rake up dead matter and fertilize with calcium nitrate or ammonium nitrate with lime. In the event of a serious attack, apply fungicidal treatment.

Grey Snow Mold / Typhula Blight (Typhula incarnata)

Grey snow mold / Typhula blight (Typhula incarnata)

Brownish spots of various sizes that appear after snowfall, the colour of which turns grey to white. The development of this disease is caused by long-term laying snow, temperatures between 0–10 degrees Celsius, and high air moisture. An abundance of waste likewise forms a microclimate, which causes the disease to thrive.

Countermeasures: Thoroughly rake up dead matter and fertilize with calcium nitrate or ammonium nitrate with lime. In the event of a serious attack, apply fungicidal treatment.

Powdery Mildew (Blumeria graminis)

Powdery mildew (Blumeria graminis)

An off-white coating that forms on blades of grass and turns into more extensive brownish spots. The grass blades gradually die. Caused by over-dense grass growth and trimmings, high air humidity, and shady areas.

Countermeasures: Growing resistance species, balanced nourishment, and frequent mowing limit the spread of the disease. In the event of a heavy outbreak, apply fungicidal treatment.

Crown Rust (Puccinia coronata Corda)

Crown rust (Puccinia coronata Corda)

Fuzzy yellow and orange bumps appear on the grass blades accompanied by chlorosis and necrosis, which turn into shiny black spots. Gradually leads to the destruction of leaf tissue. Caused by extensive piling up of chopped grass, inadequate nourishment, high temperature and air humidity.

Countermeasures: Balanced nourishment and more frequent mowing are effective in inhibiting this disease.

Stem Rust (Puccinia graminis)

Stem rust (Puccinia graminis)

Dark, rusty, fuzzy summer spore sacs appear around the joint and on the lower portion of the stalk. Later, winter spores appear dark black and bulging. This gradually leads to tissue destruction, and to the grass blades twisting up and drying out. Caused by excessive watering, frequent dew and heavy rain showers during higher temperatures.

Countermeasures: The disease can be limited by watering only during the evening hours.

Red Thread / Corticium (Laetisaria fuciformis)

Red thread (Laetisaria fuciformis)

Irregular spots appear in grassy areas, which later turn yellow and take on a rice straw colour. Pink coloured air mycelia fuzz appears during high humidity. The disease mainly strikes in autumn. Caused by insufficient nitrogen nutrients, long-term wetness, and frequent mist or fog.

Countermeasures: Effective methods of limiting this disease include regular and balanced nourishment, cutting the lawn back, and, if need be, fungicide treatment.

Fairy Rings (Marasmius oreades)

Fairy rings (Marasmius oreades)

Mushrooms of the Basidiomycetes order, which primarily emerge in older lawns, poor and sandy soil, densely packed soil, and former forest soil. It emerges looking like a dark green circle with an abundance of nitrogen from the decomposition of wood, or in the form of zones of dead grass with whitish mycelium fungus or circles of sporophores.

Countermeasures: The disease can be eliminated by replacing the topsoil layer to a sufficient depth and sowing grass mixture over the new topsoil.