The disease is less of a problem on general purpose lawns, fusarium patch disease attacks closely mown luxury lawns that contains a high percentage of annual meadow grass, this grass species being very susceptible to attack. The disease is a widespread problem on closely mown sports turf such as golf and bowling greens.
Identify fusarium patch disease
Fusarium patch disease initially appears on the lawn or in areas of turf as small patches that measure up to 50mm in diameter. The leaves turn an orangy - brown colour and are mushy. Sometimes during early mornig dews, white cobweb like fungal threads can be seen on the infected areas.As the disease quickly spreads the patches increase in size into larger patches that measure up to 300mm in diameter. As the severity of the attack increases, these patches can join together causing widespread damage to the lawn.
Conditions that favour fusarium patch disease
- Fusarium patch disease is most active during the cool and damp weather conditions typically associated with the autumn and winter months.
- Excess levels of nitrogen caused by late season applications of high nitrogen feeds will encourage fusarium patch disease.
- Areas of turf and lawns that suffer from shade lack sunlight and air movement, encourage fusarium patch disease.
- An excessive layer of thatch or organic matter build up encourages water retentive turf which in turn encourages fusarium.
- Surface alkalinity (high pH) caused by applications of lime or other materials with a high pH leaves the grass susceptible to this disease
- A lawn that contains a high percentage of annual meadow grass will always be at risk from an attack of fusarium, as this grass species is very susceptible.
Prevention and control of fusarium patch disease
- Fungicides are available for turf care professionals such as golf green keepers. Unfortunately for amateur gardeners the use of fungicides is severely limited and in many cases not allowed, therefore preventing fusarium patch is all the more important.
- Excess nitrogen is a contributing factor in many diseases including Fusarium patch disease. Avoid applying fertilisers with a high nitrogen content to late in the growing season.
- Apply an autumn / winter fertiliser at the end of the growing season with a high potash content. Potash is an important element for the grass plant during this period as it helps harden the plants against disease.
- Where possible prune back vegetation to allow more air and light into the garden. This will help keep the leaf of the grass dry which is important in preventing this disease from spreading.
- Regular mechanical operations like aeration and scarification are important to help control the thatch layer, thus helping in the fight against fusarium patch disease.
- Applications of sulphate of iron based products will help lower the surface pH therefore discouraging fusarium.
- Encourage grasses that are able to tolerate the disease as the expense of annual meadow grass.