Turf Care: Information About Turf Diseases

“Turf grass diseases are difficult to understand because the biological organisms causing the problems are rarely observed.  Fortunately, grasses maintained using proper cultural practices (water, mowing, and fertilizer) are not as likely to become diseased or be as severely damaged as grasses not receiving proper care.”


This disease is especially prevalent during warm, humid weather. The irregular shaped patches of infected areas are reddish-brown turning to yellow and tan. Younger leaves are quite often red. Treat with an approved fungicide.

Brown Patch

Brown Patch is a disease of summer and early autumn when the weather is cool and wet. The characteristic of the brown patch is the “smoke ring” with the disease. This ring of dark grey (fungus mycelium) often surrounds the infected area but disappears as the foliage dries. It is not always present. The affected areas may grow up to one metre in diameter. It does occur in all mainland states and is widespread in NSW. Treat with an approved fungicide.

Dollar Spot

The disease name comes from the dead straw-coloured spots about the size of a dollar.  Dollar spot may persist from early summer until early autumn.  It appears to be more prevalent in seasons with low rainfall, presumably from the adverse effect of low soil moisture on the grass. Treat with an approved fungicide.

Fairy ring

During the spring or summer, a circle or arc of stimulated grass or toadstools may appear in lawns.  These are called fairy rings. The rings can vary in size from a few centimetres to 20 metres in diameter.  These rings of lush growth in the lawn are caused by the release of nutrients, in particular nitrogen, from the activity of the fungus living on organic matter in the soil. The hydrophobic nature of the soil profile needs to be reversed using wetting agents and then the use of an appropriate fungicide.

Winter Fusarium

This is a common disease found in the colder months on the cool season fine grasses used in bowling and golf greens. Circular patches appear as small water-soaked spots less than 5cm in diameter. Soils that are high in nitrogen and low in phosphorous and potassium favour this disease. To fix this, balance fertility and soil pH to increase air circulation.

Helminthosporium Leaf Spot/Black

Can occur at any time of the year when there is a lot of moisture around and not much wind to dry the grasses. This causes small lesions on the leaf blades.

Pythium/Damping Off

This disease is prevalent in hot, humid weather and where there are poor drainage and air circulation. The patches of infection enlarge at a rapid rate

Red thread

Dead leaves interspersed with uninfected leaves is one of the first symptoms. Red thread commonly appears in spring and autumn during humid periods and is especially severe on slow-growing nitrogen-deficient lawns. Another noticeable symptom is the water-soaked patches of grass in the spring. Infected grass blades soon die and fade to a bleach tan colour when dry.

Rolf’s Disease

Rolf Disease generally occurs in the warm conditions of spring and summer. It comes up in circular areas of 15-45cm diameter, appearing with rings of dead grass.

Spring Dead Spot

This disease favours cool, wet weather in spring and autumn with daily temperatures of less than 15C. It appears as circular areas of dead grass, 15-30cm in diameter when turf resumes growth in spring. This is more severe on mature turf and in areas with long winters and cold temperatures.

Take All Patch

Take All Patch is mainly active in cool, wet years and poorly drained soil. The first symptom is a yellowing of the leaves and a darkening of the roots. Small, light brown dead patches appear and then continually spread. During winter the affected areas turn grey.

* Turfgrass Disease Management M.L.Elliot and G.W.Simone