Biocontrol of soil-borne plant pathogens with introduced inocula

Abstract

Despite more than 60 years of research on biocontrol of plant pathogens, introduced inocula of only two control agents are used widely and successfully against soil-borne or root-infecting pathogens in current commercial practice. Several others are undergoing exploratory commercial development or are used on a limited or local commercial scale. This review adopts a critical approach to the strategies for control of soil-borne pathogens with applied antagonists, and identifies some areas in which rapid developments could occur. In most instances it will be necessary to combine the use of microbial inocula with management practices designed to minimize disease losses. Also, in most instances, biocontrol strategies should be targeted against small pathogen populations, to prevent or delay the build up of disease, rather than to control existing high levels of pathogens. Natural, rapid senescence of cereal root cortices, which is influenced by both genetic and environmental factors, offers prospects for developing the use of weak parasites for control of take-all disease, caused by Gaeumannomyces graminis var. tritici . Recent studies on biocontrol of take-all by the fungus Microdochium bolleyi are presented, and special emphasis is given to the strategies most likely to be of value for take-all control.