Infectious hairy root disease is caused by Rhizobium rhizogenes and it occurs on many dicotyledonous plants. It was first identified as a pathogen of economic importance on apples in the early 20th century (8). The bacterium was formally named Agrobacterium rhizogenes in 1942 (1). Recently, it was discovered through the use of molecular tools that A. rhizogenes was closely related to Rhizobium spp.. Interestingly, species of Rhizobium and Agrobacterium are capable of horizontal gene transfer through the exchange of Root-inducing (Ri) plasmids (extrachromosomal structures that carry genes) in-vitro. Additionally, wild-type strains of symbiotic bacteria were isolated from root nodules of leguminous Yellow Pea-bush (Sesbania cannabina) and identified as close relatives of A. tumefaciens(=Rhizobacterium radiobacter)(7). The original classification of the bacterium as Agrobacterium was based on the pathogenicity of disease causing strains. Phylogenetic relationships based on the comparison of 16S rDNA analysis have elucidated the similarity between Agrobacterium and Rhizobium which led to the reclassification of Agrobacterium spp. as Rhizobium spp (9).