Agrobacteriumferrugineum is the correct name if this species is regarded as a separate species within a separate genus Agrobacterium.
Young et al. proposed that the type species of Agrobacterium be transferred to the Rhizobium. These authors did not, however, make any proposal regarding the transfer of Agrobacterium ferrugineum to either Rhizobium or another genus.Publication:
Young JM, Kuykendall LD, Martinez-Romero E, Kerr A, Sawada H. A revision of Rhizobium Frank 1889, with an emended description of the genus, and the inclusion of all species of Agrobacterium Conn 1942 and Allorhizobium undicola de Lajudie et al. 1998 as new combinations: Rhizobium radiobacter, R. rhizogenes, R. rubi, R. undicola and R. vitis. Int J Syst Evol Microbiol 2001; 51:89-103.