This book reports on recent advances on: (1) new methods and approaches for specific and sensitive detection and identification of Pseudomonas syringae and Ralstonia solanacearum; (2) ecology and epidemiology bases of Pseudomonas syringae that enable the development of management strategies; (3) pathogenesis and determinant of pathogenicity, and in particular, mechanisms involved in virulence and virulence gene expression; (4) evolution and diversity of the pseudomonads through multilocus sequence typing (MLST) analysis; (5) determination of pathogens associated with new and emerging diseases; (6) effect of global warming on increase and emergence of new bacterial diseases.