A disease of garlic consisting of leaf and sheath necrosis sometimes leading to soft rot and plant death is associated with several fluorescent pseudomonads, many of them classified as Pseudomonas fluorescens biotypes 1 and 5. Artificial inoculation experiments showed that only bacteria belonging to the second group (P. fluorescens biotype 5) could be regarded as pathogenic on garlic. When compared to three strains of Pseudomonas fuscovaginae (two from rice, one from wheat), almost 80 biochemical properties were similar. Rice sheaths inoculated with strains from garlic exhibited symptoms identical to those caused by the three P. fuscovaginae strains and the latter induced necrosis when infiltrated into garlic leaves. Garlic strains gave no positive reaction when tested with a P. fuscovaginae antiserum (immunodiffusion and immunofluorescence). Considering that serological properties may be variable in P. fuscovaginae, it is suggested that the pathogenic strains isolated from garlic are closely related to P. fuscovaginae.