Spot Blotch of Barley

Bipolaris sorokiniana

Description:

Dark brown, round to rectangular spots or blotches often with a yellow halo on the leaf blade and sheath. Lesions may join to form larger lesions. Severely infected leaves die prematurely. Smaller spots may appear on the heads and kill the florets or cause a black discolouration of the embryo end (Black Point) of the grain. Lodging may occur as the disease weakens the straw.

Species Affected:

Barley.

Biology:

Transmitted on stubble and seed.
Favoured by warm moist conditions.
Survives from season to season on volunteers, in crop residues and occasionally on seed.
Spores from crop residues or from green plants are spread by wind.
May be associated with Black Point in Barley.
This fungus causes Common Root Rot in Wheat and Barley.

Life Cycle:

Origin and History:

Distribution:

Usually only seen in Queensland.

Significance:

Management and Control:

Sow clean seed.
Plant less susceptible varieties. See HYPERLINK \l "_Disease_Susceptibility_of_Barley Va" Disease Susceptibility of Barley Varieties.
Avoid areas where Barley stubble is present.
Burn, bury or graze stubble before planting.
Adjust rotations so there is a longer period between Barley crops.
Avoid growing Barley in the warmer months.

Related and Similar Species:

Net Blotch - Net Form (Pyrenophora teres f. teres)
Net Blotch - Spot Form (Pyrenophora teres f. maculata)
Halo Spot (Pseudoseptoria stomaticola)

References:

Acknowledgments:

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