There is a real risk of introducingXylella fastidiosainto the EPPO region where this quarantine pest has not yet been found and constitutes a serious threat to the Mediterranean grapevine industry. Direct isolation of endophytic bacteria from imported propagation material, combined with one‐dimensional SDS‐PAGE of the total soluble proteins of the bacterial cell envelope, can be considered as a test to be used in grapevine certification schemes. The gel electrophoretic pattern ofXylella fastidiosais characterized by a constant distribution of 14 major diagnostic bands. Even without gel scanning, this relatively simple technique allows discrimination between grapevine strains ofX. fastidiosaand other xylem‐inhabiting, slow‐growing b