RHIZOBACTERIA AS BIOCONTROL AGENTS OF WEEDS

There is a current need to develop alternative weed management techniq ues in response to demands for reduction in herbicide use due mainly t o health and environmental concerns. Therefore, all possible nonchemic al strategies for weed control should be considered, including biologi cal control. Deleterious rhizobacteria (DRB), largely overlooked as po tential biological control agents for weeds until recently, are able t o colonize root surfaces of weed seedlings and suppress plant growth, Limited field studies indicate that DRB suppressed weed growth, and re duced weed density, biomass, and seed production. In this manner, crop s out-compete the suppressed weeds for growth requirements, eliminatin g the necessity for eradication of weeds in the crop. Establishment of DRB as a viable biological control strategy initially will require in tegration with other weed control approaches including other biocontro l agents, agrichemicals, and cultural and residue management practices . To achieve success, more in-depth research is needed on ecology of b acteria-plant relationships, mechanisms of action (including character ization of phytotoxins), inocula formulations, and methods to enhance crop competition.