Abstract
Pathogenicities of the crown gall bacteria isolated from chrysanthemum, marguerite and rose were investigated in relation of their biovars. These isolates were tested for their pathogenicities and inoculum potential on chrysanthemum, marguerite, rose, tomato and kidney bean. Chrysanthemum and marguerite isolates (biovar 1) were more pathogenic to their original host plants than to rose. Rose isolates (both biovar 1 and 2) were more pathogenic to rose than to chrysanthemum and marguerite. Tomato and kidney bean were also susceptible to any of the 3 isolates. Inoculation experiments with different inoculum doses of the causal bacteria showed that there were same differences in the inoculum potential of these 3 isolates.
