ABSTRACT
B. L. Jacobsen and A. Backman have stated that biological and cultural control are two alternatives to synthetic chemical pesticides in an integrated pest management program. According to J. A. Thompson, there is a worldwide effort to move toward the use of ecologically safe ”environmentally friendly” methods of protecting crops from pests and pathogens. Biocontrol agents most likely interact with pathogens by the mechanism of antibiosis and competition. Competition refers to the interaction of two organisms striving for the same thing, e.g., space and nutrients. Parasitism is an antagonistic symbiosis between organisms. Baker and P. J. Cook defined suppressive soils as soils in which the pathogen does not establish or persist, establishes but causes little or no change, or establishes and cause disease for a while but thereafter the disease is less important, although the pathogen may persist in the soil. Several advancements have been made during the last few years with regard to the field application of biocontrol agents.
