Rhizobacteria as biocontrol agents of weeds

Abstract

There is a current need to develop alternative weed management techniques in response to demands for reduction in herbicide use due mainly to health and environmental concerns. Therefore, all possible nonchemical strategies for weed control should be considered, including biological control. Deleterious rhizobacteria (DRB), largely overlooked as potential biological control agents for weeds until recently, are able to colonize root surfaces of weed seedlings and suppress plant growth. Limited field studies indicate that DRB suppressed weed growth, and reduced weed density, biomass, and seed production. In this manner, crops out-compete the suppressed weeds for growth requirements, eliminating the necessity for eradication of weeds in the crop. Establishment of DRB as a viable biological control strategy initially will require integration with other weed control approaches including other biocontrol agents, agrichemicals, and cultural and residue management practices. To achieve success, more in-depth research is needed on ecology of bacteria-plant relationships, mechanisms of action (including characterization of phytotoxins), inocula formulations, and methods to enhance crop competition.