Pythium Root Dysfunction
Causal Agent
Pythium spp.
What is Pythium Root Dysfunction?
Pythium root dysfunction is a fungal disease caused by Pythium spp. that infects grass roots and inhibits their ability to absorb water and nutrients from the soil. When turf is affected, it may appear thin, off-colour and slow growing. In cool and wet conditions, Pythium root dysfunction may first appear as small, diffuse, yellow patches of turf 4-7cm in diameter.
What are the symptoms of Pythium Root Dysfuncton?
General symptoms of pythium root dysfunction include:
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Affected turf may appear thin, off colour and slow growing. This may occur in small patches or as a general decline and loss of large turfgrass area.
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Under cool, wet conditions symptoms may first appear as small, diffuse yellow patches of turf 4 to 7cm in diameter.
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As temperatures rise, large areas of turf may wilt, turn brown and die.
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In severely infected plants, crowns may appear watersoaked and root systems are greatly reduced in volume and vigour.
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Roots and crown may be extensively discoloured.
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No foliar mycelium is evident during infection.
Pythium Root Dysfunction INFO SHEETWhat turfgrasses are particuarly susceptible to Pythium Root Dysfunction?
Cool and warm season grasses.
When does Pythium Root Dysfunction occur?
The general conditions favouring Pythium Root Dysfunction are:
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Hot days (30-35°C), humid or rainy weather when night temperatures are warm (above 20°C).
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Relative humidity exceeding 90% for at least 14 hours and a minimum temperature not falling below 20°C.
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Pythium Root Dysfunction occurs in areas with high soil moisture, poor drainage and low light.
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Areas with low mowing height and excessive wear.
What can I do to manage or control Pythium Root Dysfunction?
Management practices that can help control or reduce instances of pythium root dysfunction include:
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Water early in the day, and water infrequently and deeply.
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Removal of excessive thatch.
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Do not over fertiliser turf with nitrogen.
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Avoid mowing during moist, hot weather.
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Promote good light penetration into the turf canopy.
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Increase air circulation to speed the drying process of the turf.
