Chapter 26 - Controlling Soil-Borne Plant Pathogens

Abstract

This chapter briefly introduces some of the antagonists of soil-borne pathogens as representative of the broad taxa that are useful in this field, and then discusses ways in which these antagonists can be employed to bring about biological control of soil-borne plant pathogens. Plant-parasitic nematodes inhabit many types of soils and attack the roots of plants. They are affected by a range of natural enemies, including bacteria, nematophagous fungi, and predaceous nematodes and arthropods. Organisms for biological control of soil-borne diseases can be used primarily in two ways, either through conservation or through augmentation. Among the diversity of nonpathogenic microbes usually associated with plants, there is a substantial opportunity for the development of resident species as competitors of, or antagonists to, pathogenic organisms. Management of such antagonistic organisms for biological control can range from treatment of soil to favor the desirable organisms through inoculation of soils or plants with specific beneficial microorganisms. Biological control of plant pathogens through conservation is accomplished either by preserving existing microbes that attack or compete with pathogens or by enhancing conditions for their survival and reproduction at the expense of pathogenic organisms. Biological control of plant pathogens through augmentation is based on mass culturing antagonistic species and adding them to the cropping system.