AbstractRed core is a serious root rot of strawberry caused by P. fragariae. Despite having a 'nil tolerance' in propagation schemes and being a quarantine pest, P. fragariae has spread steadily throughout Europe such that only a few Mediterranean countries are now apparently free from it. Field inspections of nurseries are inadequate for detection of red core and a bait test, although sensitive, takes too long to be useful commercially. The European Union, through its Standards, Measurements and Testing Programme has funded the further development of prototype molecular and immunological tests for red core to routine tests that meet ISO 9002 standards. The principal thrust has been the development of a nested polymerase chain reaction (PCR), supported by immunological tests for rapid screening of large numbers of routine samples. Nested PCR has suitable speed, sensitivity and specificity for testing and is now being used routinely in some laboratories. The finished tests will be freely available to all parties after the final stage of the project, a demonstration phase in which the technique will be tested widely in Europe.