Causal fungus – Erysiphe graminis
Damage caused – The grass leaves appear to have a white, white/grey powder on their surface. During later stages the leaves will turn yellow resulting in death of many plants.
Grass species affected – Can affect most turf grass species although Perennial ryegrass (Lolium perenne), Smooth meadow grass (Poa pratensis) and Fescue grasses (Festuca spp.) are frequently affected.
Factors promoting infection – Warm dry periods, shade and poor air movement over the sward.
Prevention and treatment – Do not over fertilise with nitrogen, irrigate during dry periods. Improve light intensity the sward is subjected to and/or improve air movement