Identifying common lawn diseases in your turf

Lawn Disease

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Symptoms

Treatment

Take-All Patch

You can recognise Take-All Patch because the base of the shoots and roots become brownish black before they die.

1. Lower the pH of your soil to less than 5.5  by applying phosphorous and potassium.
2. Water your lawn less and improve the drainage of the soil as Take-All Patch thrives in poorly drained soils. 
3. If necessary remove the diseased patches and returf. 
4. Apply a preventative systemic fungicide.

Spring Dead Spot

1. Fertilise to maintain nutrition needs.
2. Supplement with potassium.
3. Improve drainage and phase back the watering as SDS thrives in moist soil.
4. Reduce thatch to below 1 cm thickness to alleviate compaction.
5. Apply a preventative systemic fungicide.

Pythium Blight

It’s most easily identified by the white, cottony fungal mycelia that you can see on the surface of the leaves in the morning.

1. Water deeply but infrequently to reduce waterlogging.
2. Reduce thatch to below 1cm thickness to alleviate compaction.
3. If necessary, aerate your lawn.
4. Pythium blight spreads easily, so clean your lawn mower blades and any other equipment after use.
5. Apply a preventative broad spectrum fungicide.

Fusarium Patch

Identifiable by the halo-like ring that can appear on the outer edges of infected areas on low-cut turf. Also by the thin covering of white mycelium that turns a pink colour in sunlight.

1. Ensure you maintain a low soil pH by amending the soil as necessary.
2. Increase air circulation through dethatching and aeration. 
3. Minimise shade.
4. Apply a broad spectrum fungicide.

Fairy Ring

It’s easily identifiable by the concentric ring of dead grass that develops inside the circle of fast growing turf. Often accompanied by mushrooms or toadstools.

1. If there are fungi in place but no accompanying dark grass, simply rake those away and dispose of them.
2. If dark grass is present you will also need to remove the turf and root zone with the soil that contains the white, cottony mycelial mass.
3. Continue with regular fertilising, mowing, thatch reduction and aeration. 
4. Apply nitrogen and iron to mask symptoms.
5. Use soil wetting agents to penetrate hydrophobic areas.

Dollar Spot

Often mistaken for drought injury or fertiliser burn, Dollar Spot is identifiable by the bleached lesions that run down the blades of the grass. And when dew is on the grass, cottony threads will appear as well.

1. Adopt a strong lawn care maintenance program including aeration, thatch and mowing.
2. Water deeply but infrequently in the morning.
3. Use a preventative fungicide that uses liquid copper or active ingredient propiconazole.

Helminthosporium Leaf Spot

On some lawn types – for example couch – white or black blotching can appear. And the lesions can look purple-black in colour. On kikuyu the lesions look solid brown to purple coloured as well.

1. Have a consistent fertilisation process paying close attention to potassium and nitrogen.
2. Water infrequently but deeply.
3. Mow your lawn regularly to the recommended height for your turf.
4. Improve air movement with aeration and dethatching.
5. Avoid herbicide applications when the disease is active.
6. Apply a preventative fungicide.