Featured Article | GreenCast | Syngenta

Keep red thread eye sores out of sight

By Mike Agnew, technical services manager for Syngenta

Red thread is a fungal infection that causes reddish-brown patches on customers’ lawns. It may kill turf in patches that are 2 – 8 inches in diameter, or the disease may occur over large areas without killing the plants. A pink web of fungal threads binds the leaves together. To help identify this disease, look for pink, gelatinous fungal crusts projecting from the leaves. 


Source: Syngenta, 2016.

​​​​​​​Conditions for development

Red thread thrives in temperatures between 40° F and 85° F, and in locations that are low in nitrogen. It also occurs in areas that experience more than 10 hours a day of foliar wetness for several consecutive days.

Control measures

  • 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 potash
  • Maintain the soil pH between 6.5 and 7.0
  • Reduce shade
  • Increase air circulation to help the turf's drying process
  • Irrigate turf deeply and as infrequently as possible

Heritage® fungicide and Velista® fungicide are ideal solutions to help control red thread. Preventive and early curative applications will provide the best results. The graph below demonstrates excellent red thread control when both products were applied curatively. 

Rutgers University, 2011


Performance assessments are based upon results or analysis of public information, field observations and/or internal Syngenta evaluations.

For more information about red thread that you can share with your customers, download our red thread door hanger.

All photos are either the property of Syngenta or are used with permission.​​​​​​​

©2020 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. Heritage®, Velista® and the Syngenta logo are trademarks of a Syngenta Group Company.

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