What is red thread?

Red thread occurs in the spring and fall during humid periods when the weather is between 16-24ºC. The disease is especially severe on slow growing nitrogen deficient turf. Bluegrasses, ryegrasses and bentgrasses can be affected. Fine leafed fescues are some ryegrasses are particularly susceptible.

This lawn disease is a parasitic form of plant life called fungi. Fungi live in the soil, thatch and dead leaves all year round. These fungi feed off the grass by drawing nutrients from it. The disease spreads throughout the lawn in the form of spores. These spores are spread by wind, air, water and humans.

How can I tell if I have red thread?

The first noticeable symptoms are water soaked patches of grass in the spring. Infected grass blades soon die and fade to black-tan colour when dry. The infected blades of grass are often interspersed with healthy grass blade giving the lawn a ragged appearance. In humid weather the fungus grows visibly on the infected grass blades and leaf sheaths. The fungus produces thread like strands or web like areas of coral pink to deep red colour on the tips of the brown grass blades. The strands can protrude up to 2cm up from the blade and are easily seen, hence the name "red thread".

If you are not certain if you have red thread disease, please call your local Weed Man Professional for a free healthy lawn analysis. They will diagnose the problem and advise you on the best treatment for your lawn.

How can red thread be treated?

Invasion of the red thread fungus is quick and grass blades may begin to die as soon as two days after becoming infected. This makes red thread difficult to control. The best treatment is to use proper cultural practices to encourage a healthy lawn.

Some of the beneficial practices to keep in mind when dealing with red thread are:

  • Maintain adequate fertility - Nitrogen deficient lawns are more susceptible to this disease. Regular applications of Weed Man's specially formulated slow release granular fertilizer [link] will provide a sufficient amount of nitrogen to the lawn.

  • Avoid over watering - Do not water in the late afternoon or evening. Leaving the grass plants wet overnight will allow the disease spores to spread more rapidly causing greater damage in the long term.

  • Thin out shaded areas - This will help dew and other moisture to more readily evaporate.

  • Provide good soil drainage and do not allow thatch levels to accumulate. This allows moisture to stay trapped at the surface in the thatch layers and assists the disease spores in spreading. Mechanical core aeration would help relieve compaction and help relieve the thatch layer. This would improve water absorption and air circulation to the root zone.

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