Pythium Foliar Blight - Grease Spot

  • Whastsapp

Causal organism: 
Pythium Spp

Pythium Foliar Blight / Grease Spot
Host Grass Types
All turfgrass species
Small, discoloured spots that can enlarge very quickly to irregular areas of dead turf. May also show as ‘frog-eyes’. Grass becomes dark and watersoaked, feeling greasy to touch. Patches are shrivelled and matted when dry. Mycelia may be present during high humidity. The infection can look streaked as it follows channels of natural drainage and paths of mowing equipment

Conditions that can favour the development of the disease

  • Common in hot summer weather (29 - 35°C) with little air movement and high relative humidity
  • Can occur at lower temperatures (20°C) when other environmental factors are conducive
  • Poor drainage and waterlogging
  • Lush, over-fertilized turf
  • The disease spreads rapidly by mycelial growth, in water and on mechanical equipment, especially mowing infected turf on dewy mornings

Management strategy to reduce the likelihood of attack

  • Optimise drainage and soil profile management to avoid waterlogging
  • Use irrigation appropriately to avoid excess soil moisture
  • Regular aeration to develop good soil structure for drainage and root development
  • Topdress to improve the soil’s structure and drainage capabilities
  • Avoid excessive nutrition
  • Reduce thatch
  • Use fungicides as part of your iTurf programme and be aware of causing resistance to one chemical group by its regular use

Pythium Foliar Blight / Grease Spot