Pseudomonas viridiflava (Burkholder, 1930; Clara 1934)

Summary. The characteristics of 12 isolates from 7 different hosts which were believed to be Pseudomonas viridiflava were studied using a variety of cultural and biochemical tests; in nutritional tests, 135 compounds were screened for their ability to serve as sole carbon and energy (C/E) sources. All cultures were similar in character and resembled closely Burkholder's original isolates: they were distinguishable from 13 cultures of other phytopathogenic Pseudomonas spp. Although they closely resembled Ps. syringae , they could be distinguished by their ability to rot potato, to utilize d (—) tartrate as sole C/E source and by their failure to utilize sucrose and to form levan on 5% sucrose nutrient agar. Pseudomonas viridiflava is a common epiphyte at least on dwarf beans (Scarlett, 1968) though it has rarely been cited as a cause of disease in Phaseolus spp. Results of lesion tests in dwarf bean pods and in the tobacco hypersensitivity test together with pectolytic activity strongly suggest however that it is a potential pathogen.