pseudomonas flavescens pseudomonas flavescens pseudomonas flavescens is a gram-negative bacterium that causes blight cankers on walnut trees. based on 16s rrna analysis, p. flavescens has been placed in the p. aeruginosa group. pseudomonas flavescens scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: pseudomonadales family: pseudomonadaceae genus: pseudomonas species: p. flavescens binomial name pseudomonas flavescenshildebrand, et al. 1994 type strain atcc 51555 ccug 49622 cfbp 5586 cip 104204 dsm 12071 lmg 18387 ncppb 3063