Wirrega Blotch of Barley

Drechslera wirreganensis

Names:

Ring Spot of Barley.

Description:

There are 2 types of lesion - a small spot and a large blotch.
The small spot is circular, dark brown and 2-5 mm wide with a light centre and little of no yellowing around the edges. The centres of the spots often rot away leaving a hole in the leaf.
The large, brown blotches may expand to cover the leaf blade and are surrounded by a yellow halo that is usually wider at the ends than the sides. The centre of the lesion may die and leave a hole in the leaf. The blotches expand and eventually cover the whole leaf. In crops many of the leaf tips are dead and withered.
Thin, black, spiky, spore producing fungal structures up to 3-4 mm long can often be seen on the ground growing from infected crop and grass residues and seed.

Species Affected:

Barley, Barley Grass, Brome Grass and other grasses.

Biology:

Occurs on most grass species and is common on Bromes (Bromus spp.).

Life Cycle:

Origin and History:

Discovered in South Australia in 1990.

Distribution:

South Australia and Western Australia.

Significance:

Management and Control:

Plant resistant varieties. See HYPERLINK \l "_Disease_Susceptibility_of_Barley Va" Disease Susceptibility of Barley Varieties.
Control grasses in the year before sowing Barley.
Use rotations where Barley follows a broad-leaved crop of grass free pasture.

Related and Similar Species:

Ring Spot of Wheat (Drechslera campanulata)
Common Leaf Spot of Wheat (Drechslera verticillata)

References:

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.HerbiGuide.com.au for more information.