Dickeya is a serious phytosanitary risk for the cultivation of seed potatoes. The Dickeya variants that occur in seed potatoes must be accurately identified, i.h.b. the new aggressive variant which is called tentatively Dickeya Solani. There sequences of virulence genes to be analyzed, in this case genes that are involved during the initial colonization of the potato plant (the new Dickeya variant appears to be specifically distinguished in these processes), and of genes for cell wall-degrading enzymes. With this MLSA data are DNA relatedness trees turned off, and these are compared with the MLSA based on a set of housekeeping genes. From this, the usefulness will prove of particular genes for the identification of the Dickeya variants, i.h.b. of Dickeya solani, from which also further DNA barcodes, and specific quantitative PCRs may arise. Further taxonomic support will be given by genomic fingerprints from PCR-melting profile, a '' AFLP light '', total DNA: DNA hybridizations and MALDI-TOF MS of representative strains. The combination of these new data, we expect to derive or Dickeya solani just a more aggressive form, or substantially different from the known Dickeya species and varieties. In function of a final consideration for Q-state is the harmfulness of representative strains from the different clusters compared in controlled pathogeniciteitstesten in potato and other cultivated plants and) plants.