Barley leaf scald
Rhynchosporium secalis is one of the most important diseases of barley, particularly in wet seasons and in high humidity areas.
It is one of the most destructive pathogens of barley worldwide, causing disease which decreases yield by up to 40% and reduces grain quality. Rhynchosporium is a polycyclic disease, with the primary inoculum including conidia produced on crop debris, infected seeds and possibly as yet unidentified ascospores. Secondary disease spread is primarily by splash dispersal of conidia produced on infected leaves, which may be symptomless early in the growing season.
Symptoms first appear as chlorotic, irregular or diamond-shaped lesions and later symptoms are typically blue-grey water-soaked lesions on leaves and leaf sheaths. Mature lesions become pale brown with a dark purple margin. As they grow they merge forming large areas of dead tissue, even destroying the whole plant green leaf area.