South (only)

Warm Season Grass

Grass species affected

Disease occurrence

  • Throughout the year
  • Pythium is a root rot disease.
  • Symptoms are usually associated with wet soil conditions, either from excessive rainfall or irrigation. Poor drainage conditions compound the problem.


  • Symptoms seen on the leaf blades result from the fungal activity on the roots and indicates a general decline in turf quality.
  • Small to large areas of grass become yellow, light-green, or brown in color and the turf begins to thin out.
  • Roots appear thin and discolored, but are not black and rotted as they are with “take-all root rot.”


  • Aerate to improve drainage.
  • 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.
  • Mow unaffected areas first and diseased areas last to avoid infecting a healthy lawn.
  • Collect and dispose of grass clippings in the garbage when pythium is present.
  • To avoid spreading the fungus, after mowing, clean the mower blades by rinsing with water and drying with a cloth.

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