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Take-All Patch [Gaeumannomyces graminis]
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| 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 lawns and
turf, 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
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| 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 and it very unlikely it will ever
return. |
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Conditions that favour Take-All Patch Disease
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- 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.
- Wet thatchy lawns are ideal for take-all to spread through the soil
particles.
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Prevention and control of Take-All Patch
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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 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.
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