Abstract
Ten isolates of causal bacterium and four isolates of its phage were obtained from mulberry leaves affected by the blight collected from several regions of Japan.
Bacteriological characteristics of foregoing pathogens were much the same as those of Pseudomonas mori (Boyer et Lambert) Stevens reported by Smith (1920), therefore the pathogen were identified as Pseudomonas mori, even though the bacterial isolates differed from each other in their characteristics, such as decomposition of xylose and rhamnose and sensitivity to phages.
Anti-P. mori serum which was obtained by means of intravenous injection of P. mori isolate S6807 to rabbit was 1:6, 400 in titer. It showed a positive reaction on an agglutination test using P. cichorii, P. striafaciens, P. phaseolicola and P. tabaci as well as P. mori isolates, while did not using another 13 species of Pseudomonas, 7 of Xanthomonas, 2 of Erwinia, and 1 of Corynebacterium.
The phage isolates were classified into 2 groups named as MP1 and MP1h by their host ranges and forms of plaque. These phages atacked P. mori alone showing the species specificity but did not any kinds of another bacteria, such as 18 species of Pseudomonas, 8 of Xanthomonas, 2 of Erwinia, 1 of Corynebacterium, 3 of Bacillus, and 1 of Escherichia. The phages formed clear plaques in the range of 20 to 24°C, and were almost completely inactivated at 48°C for 10 minutes. They consisted of a polyhedral head, 55mμ in diameter, and an extremely short tail.
