Alex Edwards, Joint MD at Inturf, advises on a common turf ailment – Fusarium patch disease
Fusarium patch disease is the most common and one of the most damaging diseases of turfgrass in the UK, which can be difficult to control.
The disease is caused by the fungus Microdochium nivale but in the past its Latin name was Fusarium nivale, hence its common name.
The fungus develops as an irregularly shaped orange-brown area of turf a few centimetres in diameter, sometimes with a white or pink fluffy growth around the edge of the patch.
The disease can occur at any time of the year and over a period of weeks these fungal patches die back and can create areas of bare ground. These gradually recover naturally if weather and soil conditions are warm enough. However, if the disease occurs in the autumn/ winter, the conditions may not be suitable for recovery until the following spring because the turf is not growing fast enough to recover quickly.
The disease can especially take hold if snow falls on the infected turf. The layer of snow insulates the disease fungus from the cold and allows it to grow beneath the snow. When this occurs it becomes commonly known as “snow mould” and more extensive damage can occur.
As with all plant diseases, the spores from this fungus are abundant, but only cause disease if environmental conditions are right for growth.
If, for example, the weather is very still, damp and mild, the grass stays wet for most of the day and Fusarium patches are likely to develop. The fungus grows in the water film on the grass leaf and that is why heavy dews and still air favour its spread.
Chemical free and cultural practices can reduce the risk of Fusarium patch disease so avoid over-feeding turf and try not to lay in damp, shady locations with still stagnant air. To keep the lawn surface dry, mow regularly to prevent the leaves of the grass becoming too long.
Air movement dries the lawn surface, making conditions less suitable for growth of fungal diseases.
The condition of the soil under the turf is also very important in defending against disease attack – a well- structured, free-draining soil will help produce healthy turf.
In most cases, the diseased area will completely recover once the grass is actively growing again.