Two Xanthomonad Pathogens, One from Acer glabrum and One from Sambucus nigra

Abstract

At the time of publication of the ISPP List of Pathovar Names and Pathotypes (2) some of the previously described bacterial pathogens were excluded for not conforming to one or more of the international standards for naming pathovars of phytopathogenic bacteria (2). Among them were two xanthomonad pathogens, viz., Xanthomonas acernea originally described from Acer trifidum (3) and X. sambuci originally described from Sambucus ebulus (6). In recent years, however, a bacterial disease affecting S. nigra and another affecting A. glabrum were observed to occur in central Idaho (U.S.A.), and both these diseases have been found to be caused by species/pathovars of Xanthomonas. This report describes the observations on these two bacterial diseases and their symptomatology, isolation, characterization and identification of the respective pathogens, and proposes reinstatement of the two pathovars that were previously invalidated.