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Red Thread

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What is Red Thread? Laetisaria fusiformis


Red thread is a troublesome disease that infects lawns across the country and spreads throughout the lawn in the form of spores. These spores are spread by wind, air, water and humans. This 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.

Red thread attacks most types of grass but is typically only found on Bermuda and Zoysia lawns in North Texas. Under ideal conditions the fungi appear as small red filaments that may be seen projecting out of the affected leaves. Other factors that may encourage the spread of the disease are poor air circulation, poor drainage and a thatch layer greater than ½“. These spores are spread by wind, air, water and humans.

Red thread is usually always caused by watering issues. A problem with specific sprinkler heads can cause disease or discoloration to occur in your North Texas lawn during the hot summer months when no rainfall occurs. Most homeowners will increase their watering in hopes of resolving the problem. Unfortunately, if the problem is due to an issue with sprinkler heads, increasing the watering will only encourage the disease, as the root cause of the issue is with the sprinkler heads in those areas.  Refer to our article on Yellow Patch to identify and resolve your sprinkler head issues. Then refer to our Watering Instructions to properly program your sprinkler controller.


Controlling red thread can be achieved through modifying your North Texas lawn's environment:

  • Thinning of trees will improve air circulation and the penetration of sunlight.
  • Core aeration will reduce the thatch layer and improve water penetration.
  • Regular applications of a balanced fertilizer will produce a healthy lawn, which is more resistant to attacks by this disease.
  • Ensuring your sprinkler heads are popping up above the lawn and that the nozzles produce a consistent, even spray pattern and are aligned properly to cover the intended area.
  • Properly programming your sprinkler controller to prevent overwatering or watering too frequently.
Have Weed Man North DFW fertilize your lawn and advise you on correct maintenance practices to ensure a healthy disease free lawn. Call (940) 648-2552 today.