VIEW ARTICLE

Characterization and Serological Comparisons of Bacteria of the Genus Erwinia Associated with Discolored Alfalfa Roots. P. A. Shinde, Former Graduate Student, Department of Plant Pathology, The Pennsylvania State University, University Park 16802; F. L. Lukezic, Associate Professor, Department of Plant Pathology, The Pennsylvania State University, University Park 16802. Phytopathology 64:871-876. Accepted for publication 23 January 1974. DOI: 10.1094/Phyto-64-871.

Several isolates of Erwinia spp. bacteria originally isolated from discolored roots of alfalfa (Medicago sativa L.), were subjected to selected physiological and nutritional tests. These bacteria were gram-negative, nonspore-forming, encapsulated rods with peritrichous flagella. They were oxidase-negative, unable to utilize lactose and rhamnose, lacked pectinase, and metabolized glucose fermentatively. These characters suggest that the alfalfa isolates belong to the ‘amylovora’ group of the genus. The comparison of certain physiological and serological characters of six Erwinia isolates from alfalfa with three known phytopathogenic Erwinia spp. showed that the former isolates were distinct from the other described phytopathogenic species of the ‘amylovora’ group. We propose the name E. amylovora var. alfalfae. A serological comparison showed that four of the six isolates tested produced a reaction of identity in gel-diffusion tests.