RED THREAD

Laetisaria fuciformis

Causal Agent:

Laetisaria fuciformis

Susceptible Turfgrass:

Cool season turfgrasses

Symptoms:

• Circular or irregularly shaped, small to large patches (5 to 15 cm) in diameter of infected grass become water-soaked and die rapidly
• First symptoms observed is the tan colour of dead leaves
• Dead leaves are generally interspersed among uninfected leaves giving an overall diffuse, scorched or ragged appearance to the patch
• Only the foliage is infected and death usually proceeds from the leaf tips downwards
• Pink to pale red or orange fungal growths (red threads) may extend up to 10mm beyond the leaf tips
• Pink, cottony flocks of mycelium may be produced
• When red threads or flocks are present, the patched of blighted grass take on a reddish, pink or tan cast that is easily detected.

Conditions Favouring Disease:

• Foliar wetness, heavy dews, light rains and fog resulting in more than 10 hours a day of foliar wetness for several consecutive days
• Thrives in temperatures between 17°C to 29°C
• Severe when potassium, phosphorus, calcium and nitrogen are deficient
• Read Thread causes disease primarily during periods when grass is growing slowly as a result of low temperatures, drought or inadequate fertility.

• Management Tips:

  • Mow turf frequently and collect clippings to remove diseased portions of the leaves
  • Maintain adequate nitrogen and a balanced fertility
  • Apply moderate to high amounts of phosphorous and potassium
  • Maintain the soil pH between 6.5 to 7.0
  • Reduce shade.
  • Increase the air circulation to the turf'
  • Irrigate turf deeply and as infrequently as possible
  • Avoid frequent watering in the late afternoon

  General comments:

  This disease is particularly difficult to diagnose when red threads or cottony flocks are not present.

  Distribution:

  New South Wales, Australian Capital Territory, South Australia, Victoria, and Tasmania

   

Management Tips 

• Collect clippings from affected areas to remove fungal growth and diseases portion of leaves.
• Maintain adequate nitrogen and a balanced fertility.
• Apply moderate to high amounts of phosphorous and patassium.
• Mainatain soil pH between 6.5 and 7.0.
• Reduce shade.
• Increase air movement.
• Avoid frequent watering in late afternoon.

Fungicidal control

The following products have label recommendation for Red Thread control in Austarlia: 

 Refer to label for full details.

Suggested Programme

Contact Syngenta for assistance in creating a custom GreenSure Plan for your course.