Take-All Patch [Gaeumannomyces graminis]

Take-all Patch Disease
Take-all patch disease is one of the most damaging lawn diseases, thankfully it is not all that common. Take-all patch is caused by the fungus Gaeumannomyces graminis, it was formerly known as Ophiobolus graminis hence its former name of Ophiobolus patch disease. This fungus kills the roots and stems of bent grass in lawns and turf and dying bent grass is easy to pull from the turf due to the rotting roots.
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Identification of Take-All Patch Disease

This disease first appears in mid summer usually around June, it first appears in small circular patches expanding to 50cm - 100cm across affecting only the bent grass in the sward. Patches or resistant grasses and weeds may be seen in these dead or dying rings of straw coloured bent grass. As the condition deteriorates these patches can join together affecting a large area. Take-all patch will eventually disappear after December but can keep returning for several years. Eventually it will disappear all together as the antagonistic bacteria suppresses the disease. Once this happens, it very unlikely it will ever return.
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Conditions that favour Take-All Patch Disease

  • An application of any material such as lime that raises the pH of the root zone will encourage take-all patch disease.

  • A soil that has a nutrient deficiency.

  • A light sandy soil, lighter soils are naturally lower in antagonistic bacteria which suppress the fungus that causes Take-all patch disease.

  • Wet thatchy lawns are ideal for take-all patch to spread through the soil particles.

 

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Prevention and control of Take-All Patch

Once you have this disease it is very difficult to control without fungicides, therefore prevention is better than cure. As fungicides are not available to the amateur gardener cultural methods will need to be employed. These include:

  • Avoid any practices such as liming which will raise the pH of the soil. If you need to lime, apply regular applications of lawn sand or iron sulphate afterwards to acidify the lawn surface to prevent take-all patch.

  • Over seed with a resistant grass seed mixture, such as fescue and ryegrass which are not affected by the disease.

  • Maintain adequate fertility with a balanced fertiliser program. It is also thought applications of magnesium can have an effect on suppressing the disease.

  • Aerate to remove any surface water as take-all spreads in wet soils. Aerating will also help increase the bacteria in the soil to inhibit the disease.

  • Scarify to remove any excess thatch and organic matter on which the disease lives on.