Identification of the disease is relatively easy, with the turf grass having irregular tan/orange coloured spots of damaged grass, varying in size (20-35mm) with a pale pink/white colour mycelium.
Initial symptoms are seen as small orange / brown spots, which will rapidly enlarge and cause scarring of the turf when conditions are favourable. These scars will be difficult to heal and repair during the winter months, so early recognition and treatment is important to reduce scarring of the turf surface.
All mature turf containing the following grass species will be susceptible to an attack of fusarium:
(Annual meadow grasses)
Poa is the most commonly attacked, however, this grass is able to recover easily because of its seed bank presence within in the soil.
Spores can remain viable for up to two years and they can be spread by wind, water, and by foot traffic. These spores germinate infecting new plant tissue (pale pink and white mycelium), which can be seen around the edge of the patches, indicating that the disease is active.
In severe infections, the fungus may penetrate as far as the crown, but will usually not kill the plant. Infected turf will generally recover when the plant becomes more active in the spring and is able to produce new healthy leaves, restoring its vigour and colour.
The fungal pathogen has a disease life-cycle, which continues when conditions are favourable. Understanding this cycle will enable you to control the pathogen by effective management to break the cycle of disease.
Keeping the sward healthy, and reducing the conditions that favour this disease should be the first priority:
• Carry out programmes of aeration to help keep the surface free draining
• Prevent moist conditions remaining on the surface by brushing surface to remove dew
• Apply a balanced fertiliser low in Nitrogen (less than 3-4%) to keep the sward healthy
Look to remove thatch layers, as thatch provides a good environment for the disease.