South Africa Turf Disease Guide - Pythium Blight

Disease and Insect Control
South Africa Turf Disease Guide - Pythium Blight

Causal Agent:

Pythium aphanidermatum, other Pythium species

Susceptible Turfgrass:

Most species of warm and cool season turfgrass


Pythium Blight appears suddenly during hot, humid weather. This disease causes greasy, brown circular spots that are initially about 2 cm to 5 cm in diameter and then rapidly enlarge in size. The spots are water-soaked and dark-coloured early in the morning. They also form fluffy white masses of fungal mycelium (cottony blight) and can coalesce to form large, irregular areas of dead turf. Infected patches may appear brownish-orange in colour.

South Africa Turf Disease Guide - Pythium Blight

Conditions Favouring Disease:

Pythium Blight favours night temperatures of over 20°C. It occurs in areas that experience more than 10 hours a day of foliar wetness for several consecutive days. It is found in the wettest areas of turf and in areas with poor drainage and air circulation. Lush-growing turf growing under nitrogen fertilization is particularly susceptible to the disease.

  • Integrated Turf Management Tips:
  • Avoid mowing wet turf when the foliar mycelium is evident to minimise spreading the disease • Reduce thatch
  • Avoid excessive nitrogen application during hot weather
  • Increase air circulation to speed the drying process of the turf
  • Minimise the amount of shade
  • Irrigate turf early in the day. Avoid late-day watering
  • Improve soil drainage
  • Irrigate turf deeply and as infrequently as possible and Bermudagrass

Find out more about Pythium Blight by visiting our specialist horticulture website here.

Just tap the links below to read about other turf diseases. Or download the full free guide at the bottom.

  1. Anthracnose
  2. Brown Patch 
  3. Brown Ring Patch (Waitea Patch) 
  4. Dollar Spot 
  5. Fairy Ring 
  6. Superficial Fairy Ring 
  7. Grey Leaf Spot 
  8. Large Patch 
  9. Microdochium Patch 
  10. Powdery Mildew 
  11. Pythium Blight 
  12. Pythium Root Rot (Root Dysfunction) 
  13. Red Thread 
  14. Rhizoctonia Zeae (Rhizoctonia leaf and sheath spot) 
  15. Rusts: Crown, Leaf and Stem 
  16. Spring Dead Spot 
  17. Summer Patch 
  18. Take-all Patch  and
  19. Take-all Root Rot 

If you would like to have a complete copy with all the turf diseases, you can download it on the link below.

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Download the full guide here (14.41 MB).