Plant Pathogen Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, UK. lpritc@scri.ac.uk|Plant Pathogen Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, UK. lpritc@scri.ac.uk|Plant Pathogen Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, UK. lpritc@scri.ac.uk|Plant Pathogen Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, UK. lpritc@scri.ac.uk