The wilt diseases of dahlia and beans were produced during the high temperature of summer. The wilt di s e ases of dahlia is identical with the one which Dr. S. HORI had described previously. Being the d iseases of the vascular boundles, when the affected area is cross sectioned, discoloration of the vascular bundles is noted. When it is observed microscopically the vessels were found to be filled with the causal bacterial organisms. The two strains of the bacteria from dahlia and beans respectively, together with the two known strains of Bacterium solanacearum isolated from tobacco and tomato were all cross inoculated separately into four plants mentioned above. Every plant showed the typical wilt symptoms. The two varieties of bacteria, when compared physiologically, are identical with Bacterium solanacearum.