Ramularia collo-cygni - an enemy in waiting

Ramularia collo-cygni, the agent responsible for Ramularia leaf spot disease of barley, possesses many mechanisms for avoiding detection by the host, which enables it to survive as an endophyte for much of the plant’s life cycle before eventually turning pathogenic. The fungus has also eluded farmers and scientists for decades as it is a late season disease that often displays symptoms after the last possible fungicide intervention when crop scouting for disease has been completed. Visual symptoms are also hard to distinguish from other pathogens which has resulted in misdiagnoses. The ability of the fungus to spread not only via infected seed, but also on infected straw and wind dispersal, coupled with its ability to rapidly evolve resistance to fungicides, has resulted in an escalation in the perceived threat it presents to barley production worldwide. A greater understanding of the plant-fungus interaction is required if future control strategies are to be successful.