What is pythium?

Pythium is a parasitic form of plant life called fungi. Fungi live in the soil, thatch and dead leaves all year round and feed by drawing nutrients from the grass. During cooler parts of the season, the fungi grow slowly and generally do not infect foliage. Some species cause the roots to rot during cool wet weather. When weather turns hot and humid the fungi grow extremely rapidly causing infection and discolouration in a matter of hours. Pythium is primarily found on poorly drained soils with a pH greater than 7.0 and is increased by high nitrogen fertility.

How can I tell if I have pythium?

The symptoms of Pythium include:

  • Early symptoms appear as small reddish brown spots ranging in size from 3 to 15cm with a slimy or greasy texture increasing rapidly in size. If temperature and humidity remain high, the spots may coalesce and large areas of turf can be lost in as little as 24 hours.

  • During damp periods, such as early morning, the water soaked leaves collapse and become matter together by a cottony purplish-gray or white mass called mycelium. As the grass dries, the mycelium disappears and the damaged blades turn brown.

  • Damaged areas of lawn will often show up as long streaks due to the spread of spores and mycelium by mowing equipment or that pythium follows drainage patterns

If you are not sure if your lawn is suffering from Pythium, call your local Weed Man Professional for a free healthy lawn analysis. They will diagnose the problem and make recommendations on the best treatment plan for your lawn.

How can pythium be treated?

Pythium is very difficult to treat since it occurs so rapidly. The best defense is to use cultural techniques to encourage a healthy lawn. These techniques include:

  • Reduce shade and increase air circulation by thinning trees that overhand your lawn

  • Correct any soil drainage problems in your lawn as this is the primary cause of pythium spreading. Lawn core aeration would help to relieve compaction and decrease thatch to improve water absorption and air circulation to the root zone

  • Use infrequent deep watering. Make sure your lawn is receiving 2.5 to 4 cm of water weekly

  • Avoid watering or mowing during periods when the disease is active. The disease spores can be spread by your gardening equipment or just by walking across it

  • Avoid watering and mowing your lawn at night. This allows the blades to stay wet and gives favourable conditions for the spores to spread. Water early in the day so that the plant's leaves are dry by nightfall

  • Provide proper fertility. Excess nitrogen can promote the spread of pythium. Regular applications of Weed Man's exclusive slow release granular fertilizer will provide your lawn with the correct levels of nutrients including nitrogen.

If you have any further questions about pythium in your lawn or have any other questions or concerns, please feel free to contact your local Weed Man Professional.