The disease is found everywhere that barley is grown, but only causes significant yield losses in warm, humid climates.
The spots merge, eventually forming irregular necrotic patches on the leaves.
Spores are produced on barley debris in the spring and are dispersed by wind and rain.
Temperatures above 20°C and moist humid conditions within the crop canopy favour spot blotch development.
Conducive weather conditions may favour successive production of new spores and lesions leading to rapid disease development during the growing season.