Abstract
A new bacterial disease of paper mulberry (Broussonetia kazinoki×B. papyrifera) was found out in Tottori Prefecture in Japan in 1978. This disease was characterized by small leaf spots, shoot blight and the resulting dieback, and it was named bacterial blight of paper mulberry. The causal bacterium was classified as a group of Pseudomonas syringae. Comparative examinations of pathogenicity (host range) and bacteriological properties among the present bacterium and two P. syringae pathovars, mori and cannabina, pathogenic to moraceous plants were conducted. The present bacterium was pathogenic to paper mulberry, B. kazinoki and B. papyrifera but not mulberry and hemp, and therefore it was clearly distinguished from other two pathovars in their host range. From the results, it was concluded that the present bacterium isolated from paper mulberry is a new pathovar of Pseudomonas syringae. We propose to name Pseudomonas syringae pv. broussonetiae pv. nov. Strain Koz 8101 (MAFF 810036) is designated the pathotype strain, and has been deposited at MAFF collection together with three reference strains (MAFF 810037, 810038 and 810039).
