桑細菌

The bacterial blight of mulberry, caused by Bact. Mori BOYER et LAMBERT emend F.F.S. is one of the most important diseases of the mulberry tree. In field observation this organism is always found associated with the non-pathogenic yellow bacteria specially in the later stage of the disease. The present investigation was undertaken to ascertain the relation between the pathogenic organism and its attendant. In mixed culture in the media of cane sugar broth and beef bouillon, those two bacteria, one to another, show a conspecuously antagonistic action and the growth of Bact. Mori is especially depressed in the presence of yellow bacteria. The cause of the antagonistic action is still uncertain, but from the results of my experiments it can be supposed that the higher acid or basic reaction of media produced by the growth of its attendant leads Bact. Mori to self-destruction. Optimum temperature for growth of Bact. Mori is 21 to 24℃., while the attendant 27 to 30℃.; this difference may be also responsible for the cause of their antagonistic action, at least in the later stage of the disease, where Bact. Mori is not able to attain its vigorous growth owing to its unfavoarable temperature. In the artificial culture, there is no production of toxic substances which is the cause of antagonism. The quantities of glycerine, natrium asparaginate and other chemical substances added to USCHINSKY's solution as the source of carbon or nitrogen make the difference for the growth of those bacteria. But the difference of their growth is comparatively little and not enough to be accountable for the antagonistic action of those bacteria.