FUSARIUM PATCH

Causal Agent:

Microdochium nivale

Susceptible Turfgrass:

Wintergrass, Bentgrass, Fescue, Ryegrass & Kentucky Bluegrass

Symptoms:

• Circular patches appear as small, water-soaked spots less than 5 cm in diameter
• Patches change in colour from orange-brown to dark brown and finally to a light gray
• Spots may enlarge indefinitely, but are usually less than 20cm in diameter
• On low-cut turfs, ring like patches "smoke rings" may appear, the outer ring of the patch may have a water-soaked, greenish black margin
• In very wet conditions a thin to fluffy covering of white mycelium may be seen on matted leaves
• The mycelium is white, but on exposure to sunlight induces spore production which is a pink colour

Conditions Favouring Disease:

• More than 10 hours a day of foliar wetness for several consecutive days
• Cool temperatures
• Soil high in nitrogen fertility and low phosphorous and potasssium.
• Areas with slow growing conditions and heavy thatch.

Management Tips:

• Maintain balance fertility.
• Avoid using lime. Alkaline soils enhance disease development.
• Maintain low soil pH
• Use slow release fertilisers when fertilising in Autumn
• Increase air circulation to speed turf's drying process.
• Minimise the amount of shade.
• Avoid excessive thatch.  

General comments

Symptoms are evident from May to September in the southern states of Australia

Distribution:

New South Wales, Victoria, South Australia and Tasmania.

Management practices

• Preventative fungicide program during high risk periods. 
• Ensuring adequate drainage and manage the turfgrass to reduce surface moisture.
• Keep thatch layers to a minimum.
• Light penetration (especially morning sunlight) and airflow should be encouraged to dry the turf surface quickly.
• Use acidifying fertiliser such as ammonium sulphate to help reduce the pH at the turf surface.
• Avoid heavy applications of topdressing in conducive conditions.
• Apply iron to help harden the plant against infection prior to the onset of conducive conditions.
• Avoid using lime as alkaline soils enhances disease development.
• Use slow release fertilisers when fertilising in autumn.

Fungicidal control

The following products have label recommendation for Winter Fusarium control in Australia:  

Refer to label for full details.

Suggested Programme

Contact Syngenta for assistance in creating a custom GreenSure Plan for your course.