It is well established that the pectinolytic bacteria Pectobacterium atrosepticum (Pca) and Dickeya spp. are causal organisms of blackleg in potato. In temperate climates, the role of Pectobacterium carotovorum subsp. carotovorum (Pcc) in potato blackleg, however, is unclear. In different western and central European countries plants are frequently found with blackleg from which only Pcc can be isolated, but not Pca or Dickeya spp. Nevertheless, tubers vacuum-infiltrated with Pcc strains have so far never yielded blackleg-diseased plants in field experiments in temperate climates. In this study, it is shown that potato tubers, vacuum-infiltrated with a subgroup of Pcc strains isolated in Europe, and planted in two different soil types, can result in up to 50% blackleg diseased plants. All three pathogens can cause tuber rot during storage, whereas infections of seed potatoes with Pca and Dickeya spp. can also result in the occurrence of various field symptoms, including reduced emergence, chlorosis, wilting, tuber and stem rot, blackleg, haulm desiccation and plant death (Pérombelon and Kelman 1980;Pérombelon 1992;Fraaije et al. 1996;Helias et al. 2000). These symptoms can be caused by Pca as well as by Dickeya spp., making identification of the causal organism by visual observation in the field unreliable. Regulatory field inspections in seed potatoes in many countries are therefore based on recognition of this 'blackleg complex' without discriminating between the various blackleg-causing organisms.