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 approved fungicide.
This is a disease of summer and early autumn, when the weather is cool and wet. The characteristic of brown patch is the “smoke ring” with the disease. This ring of dark gray (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 approved fungicide.
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 approved fungicide.
During the spring or summer a circle or arc of stimulated grass or of toadstools may appear in lawns. These are called fairy rings. The rings can vary in size from a few centremetres 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.
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. Balance fertility and soil pH, 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.
This disease is prevalent in hot humid weather and where there is poor drainage and air circulation. The patches of infection enlarge at a rapid rate
Dead leaves interspersed with uninfected leaves is one of the first symptoms. Occurs in spring and autumn during humid periods. The disease 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.
Occurs in the warm conditions of spring and summer. Circular areas of 15-45cm in diameter appear 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 longer winters and cold temperatures.
Take All Patch
Take All Patch is mainly active in cool, wet years and in 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