RLS has a complex life cycle starting with infected seed.
(None of the available seed treatments control RLS). The
disease then grows unseen within the plant before it causes
symptoms, usually after barley flowers.
If trash from a previous barley crop is present spores from this
source can infect a crop during the season.
Spring rainfall and also periods of high light intensity following
flowering favour RLS.
Yield losses of 20% have been recorded.