Institution: | a Rothamsted Research, West Common, Harpenden AL5 2JQ, UK b Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK c Epidemiology Research Unit, SAC, West Mains Road, Edinburgh EH9 3JG, UK d Syngenta, Jealott’s Hill International Research Centre, Bracknell RG42 6EY, UK |