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Etiology

Bacterial Leaf Blight of Syngonium Caused by a Pathovar of Xanthomonas campestris. Robert S. Dickey, Professor, Department of Plant Pathology, Cornell University, Ithaca, NY 14853; Cathy H. Zumoff, Research technician, Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Phytopathology 77:1257-1262. Accepted for publication 20 March 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-1257.

The bacterial leaf blight pathogen of Syngonium podophyllum was determined to be a xanthomonad. The pathogen was readily isolated from affected leaf surfaces, transferred on fingers from affected leaf surfaces to agar medium, and spread from infected to healthy leaves by overhead watering. It was not isolated from nodal and adjoining stem sections to which infected leaves were attached. Healthy plants were produced from stem cuttings removed from above the infected leaves of subirrigated plants. The strains of the Syngonium pathogen produced similar symptoms on leaves of three cultivars of S. podophyllum that were petiole- or spray-inoculated. The pathogen was identified as Xanthomonas campestris and was found to be phenotypically different from seven selected pathovar strains. Only three of the seven pathovar strains produced any reaction in S. podophyllum; the reactions, however, were distinctly different from those produced by the Syngonium strains. We propose that the pathogen be designated Xanthomonas campestris pv. syngonii pv. nov.