Red Thread


Red thread grass disease


North (only)

Cool Season Grass

Grass species affected

  • Fescues
  • Kentucky bluegrass
  • Rye grass

Disease occurrence

  • Early-spring


  • Pinkish-red threads form around leaf blades and bind them together.
  • The red threads will be most visible when the lawn is wet. You may also see red spores on your mower and shoes.
  • The affected turf will eventually turn brown.


  • Regular aeration and dethatching are the best lawn care practices to prevent red thread.
  • Mow at the proper height for your grass species.
  • Reduce the amount of shade on the lawn as you are able.
  • Mow unaffected areas first and diseased areas last to avoid infecting a healthy lawn.
  • Collect and dispose of grass clippings in the garbage when the red thread disease is present.
  • To avoid spreading the fungus, after mowing, clean the mower blades by rinsing with water and drying with a cloth.
  • A regular fertilization schedule will help eliminate one of the primary causes of red thread. Maintaining proper levels of nitrogen and phosphorus has been correlated to decrease a lawn’s susceptibility to red thread.
  • Water deeply and infrequently early in the day to allow the leaf blades to dry off and not remain wet for long periods of time.

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