Abstract
To search the infection source of bacterial seedling blight of rice, we tried to isolate the pathogen, Pseudomonas plantarii, from weeds around the paddy field using the dilution plating method with modified medium of Azegami et al. in 1991. Weeds belonging to 28 genera within 16 families were collected in Mogami-machi, Yamagata Prefecture and used for the isolation. Twelve isolates obtained from kouyawarabi (Onoclea sensibilis), creeping buttercup (Ranunculus silerifolius), cranesbill (Geranium nepalense) and wild strawberry (Duchesnea chrysantha) formed the pathogenic bacterium-like colonies on the plate. The isolates induced the symptoms similar to those by the control strain to rice seedling and kouyawarabi. On the basis of their pathogenicity tests and bacteriological characteristics, the present isolates were identified as Pseudomonas plantarii Azegami et al. 1987. This is the first report that P. plantarii is isolated from weeds other than grasses.
