Barley Scald

Washington State University Bulletin

SP0004 - 1993

Diseases of Washington Crops

Otis C. Maloy and Debra Ann Inglis

 

Small Grains Home * Wheat Diseases * Barley Diseases

Cause

Hosts

Symptoms and Signs

Disease Cycle

Control

1997 PNW Pesticide

Recommendations

Another Picture

Other interesting Barley Scald sites

Barley leaf scald is a common and conspicuous disease of barley but usually is not serious enough to warrant control.

Cause
Scald is caused by Rhynchosporium secalis, a fungus that develops a superficial, loose stroma on which conidia are produced from short cells. The conidia have two unequally sized cells. The terminal cell hooks into a beak. Numerous pathogen races have been differentiated on different barley cultivars.

Hosts
Barley is the only important host, but the fungus can also attack rye and some grasses.

Symptoms and Signs
Scald develops on leaves as oval to irregular blotches that have a bluish green, water-soaked appearance (Photo 19). As the tissue dries, the lesion changes to brown, then to light tan bordered by a brown margin. The lesions often have a zonate or "scalded" appearance.

Disease Cycle
The fungus over-winters on dead leaves and in seed. It survives longest in residue above the soil surface. The fungus produces abundant conidia on wet lesions during cool, damp weather after the leaf tissue has become necrotic. Conidia, spread by wind and splashing rain, infect young leaves of spring- planted grain. Optimum temperatures for sporulation and infection range from 59 to 68F. Hot, dry weather stops the disease, but new infections may occur in the fall.

Control
Cultural. If scald is severe enough to warrant control, rotating crops, plowing under diseased plant residue, and destroying infected volunteer barley and grasses can help reduce inoculum.

Resistance.Some resistant barley cultivars are available, but these may not be adapted to the Northwest. The cultivar, 'Luther,' is quite susceptible and may suffer damage in western Washington.

According to the PNW Plant Disease Control Handbook, 'Gwen', 'Hundred' and 'Kold' are resistant to some strains of the fungus. The handbook also has fungicide recommendations.

Reference
Webster, R.K., L.F. Jackson, and C.W. Schafer. 1980. Sources of resistance in barley to Rhynchosporium secalis. Plant Disease 64:88-70.

Other Interesting Barley Scald sites:
"Scald," Alberta Agriculture, Food and Rural Development -- description and pictures.

"Barley Scald," Integrated Disease management in Small Grains, Virginia Cooperative Extension -- pictures and links to descriptions.