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South Africa Turf Disease Guide - Grey Leaf Spot

Disease and Insect Control
17.11.2021
South Africa Turf Disease Guide - Grey Leaf Spot Golf Courses

Causal Agent:

Pyricularia grisea

Susceptible Turfgrass:

Bermuda, Kikuyu, Perennial Rye and Tall Fescue

Symptoms:

The symptoms of Grey Leaf Spot vary depending on the grass cultivar. On Kikuyu, Grey Leaf Spot first appears as small, brown spots on the leaves and stems. The spots quickly enlarge to approximately 0.5 cm in length and become bluish-grey in colour and oval or elongated in shape. The mature lesions are tan to grey in colour and have depressed centers with irregular margins that are purple to brown in colour. On Perennial Ryegrass and Tall Fescue, symptoms first appear as small, water-soaked lesions that turn brown. Lesions may have a yellow halo. The leaf tips will have a twisted or fishhook shape.

Conditions Favouring Disease:

Grey Leaf Spot favours temperatures between 26°C to 32°C. It is also found in areas with high nitrogen levels and that are stressed by various factors, including drought and soil compaction. This disease is most severe during extended hot and humid periods.

South Africa Turf Disease Guide - Grey Leaf Spot

Integrated Turf Management Tips:

  • Avoid medium to high nitrogen levels during mid-summer
  • Irrigate turf deeply and as infrequently as possible to avoid water stress
  • Allow water to remain on leaves for only a short period of time
  • Reduce thatch by vertical cutting
  • When possible, plant turfgrass that is resistant to Grey Leaf Spot
  • Avoid using herbicides or plant growth regulators when the disease is active • Apply penetrant fungicides on a preventive basis.

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.

PDF iconDownload the full guide here (14.41 MB).