BROWN PATCH
Causal Agent
Rhizoctonia solani
Susceptible Turfgrass
Wintergrass, Couch, Bentgrass, Fescues, Kentucky Bluegrass, Ryegrass & Buffalo grass
Symptoms
- Brown discoloured circular patches, from a few centimetres up to a metre in diameter, sometimes with a smoke ring of mycellium around the edges.
- "Smoke rings" appear as thin brown borders around the diseased patches in the early morning.
- Infected leaves are water-soaked and dark, later dying and turning dark brown.
- After the infected leaves die, new leaves can emerge from the surviving crowns.
- On wide bladed species, leaf lesions develop with tan centres and dark brown to black margins.
Conditions Favouring Disease
- High relative humidity and temperatures of over 28 C during the day and over 15 C at night.
- More than 10 hours a day of foliar wetness for several consecutive days.
- Turfgrass species are most affected when night temperatures are consistently above 20 C with high humidity or moisture.
General Comments
- The symptoms of Brown Patch can vary depending on the grass cultivar, climatic and atmospheric conditions, soil and intensity of the turfgrass management.
- Brown Patch infestation is more severe when the turf is cut to a height less than the optimum for the turfgrass being grown.
Distribution
Found in all Australian states