Abstract: Water extracts from the roots of tomato,chili pepper,plantain banana and chive were tested for their effects on the growth,pathogenicity and efficacy of the vaccination bacterium,FJAT-1458,in controlling Ralstonia solanacearum(FJAT-91).It was found that the root extracts exhibited varied effects on the growth characteristics of microbes.The extracts of tomato,chili pepper and plantain banana roots promoted the growth of FJAT-1458,while those of tomato and chili pepper roots enhanced the growth of both FJAT-1458 and FJAT-91.Among the extracts,the tomato extract showed a most significant growth effect on both strains,as the bacterial counts of FJAT-1458 and FJAT-91 increased 28and 30 times,respectively,as compared with control after a 32 hincubation.In contrast,the chive extract killed them in 8hours.Further study showed that the attenuation indices on FJAT-1458 and FJAT-91 were not significantly different among the various extracts.And,these root extracts,except chive,showed no significant effect on the control efficacy of FJAT-1458 toward R.solanacearum.