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Leaf Spot / Melting-Out

Caused by: Drechslera spp. and / or Bipolaris spp.

 

Susceptible Turfgrasses
Creeping Red Fescue, Kentucky Bluegrass, Annual Bluegrass, Perennial Ryegrass, tall Fescue, and some varieties of Bentgrass and Bermudagrass.

 

Description
Leaf Spot (melting-out) causes purplish-brown to black spots with tan centers on the leaf blade and sheath. The lower leaves of the infected plants become shriveled and blighted. When melting-out infection is severe, almost all of the leaves and tillers die, causing severe thinning of the stand-or melting-out.

On cool-weather turfgrass, melting-out typically follows the appearance of leaf spots.

 

Conditions favouring Disease
Leaf spot favours temperatures between 4°C and 26°C. It occurs in areas that experience more than 10 hours a day of foliar wetness for several consecutive days. It also favours high amounts of nitrogen and a low mowing height.

 

Integrated Turf Management

  • Increase the height of cut

  • Reduce turf stress by using lightweight equipment.

  • Avoid the application of high rates of water-soluble nitrogen in the Spring

  • Minimise the amount of shade

  • Irrigate turf deeply and as infrequently as possible

  • Reduce thatch in the early Spring or Autumn for cool-season turfgrass and in the Summer for warm-season turfgrass

 

Fungicidal Control
Banner, Daconil WeatherStik and Heritage have label recommendations for Leaf Spot / Melting Out in South Africa.

Bipolaris and Drechslera (previously classified as Helminthosporium fungi).Helminthosproium sp. are on the Daconil label.