Brown blight (BB) is caused by the fungus Pyrenophora lolii. It is most common in spring and autumn, but damage can occur all year.

 

Species affected

Ryegrass, fescue, cocksfoot.

 

Identification

BB causes leaf lesions of various shapes and sizes. These consist of small, oval, brown spots, the centres of which become light brown to white as they enlarge. Longer, dark brown streaks also appear. Infected leaves turn yellow and die from the tips.

 

Spread

BB survives on dead and diseased plant tissue. It is spread by wind, rain, equipment or animals. In moist conditions, spores germinate, causing new infections. BB spore banks are often found in nearby undeveloped areas (fence lines and roadsides)

 

Prevention and management

Timely cutting and grazing minimise damage from BB. 

 

 

Brown blight on ryegrass leaves.