Rhizobacteria are being evaluated for promotion of plant growth and for biological control of weeds, insects, diseases, and nematodes. Although considerable efforts have been allocated to this approach to biological control, commercial success remains elusive yet intriguing. In this review, the root biology of downy brome and winter wheat is described as an initial model of the information needed for other plant hosts. A limited review of rhizobacteria in disease management is presented to demonstrate the potential and some limitations with rhizobacteria as biocontrol agents. Several techniques are described to improve the survival of a rhizobacterium to suppress downy brome. To achieve success with rhizobacteria in pest management, more information is needed on the root biology of the host plants and the ecology of the rhizobacteria.
