Role of inoculum sources in Rhynchosporium population dynamics and epidemics on barley.

Rhynchosporium leaf blotch of barley, caused by the fungus Rhynchosporium secalis, is of increasing importance in world agriculture. It is the most serious disease of winter and spring barley in the UK, causing substantial losses nationally, despite expenditure of £50M per year on fungicides. The disease is difficult to control with fungicides and severe epidemics may appear suddenly. The sources of inoculum responsible for starting such epidemics are not well understood.