How they work There are four mechanisms by which biocontrol agents control other microorganisms. Most biocontrol agents apply one or more of these mechanisms in the process of interacting with other mircoorganisms. This is typically a fungus or bacterium that grows very fast and overwhelms the target organism. The target organism is suppressed due to lack of food and space. The biocontrol agent produces a chemical compound such as an antibiotic or some type of toxin that kills or has a detrimental effect on the target organism.
Many microorganisms produce antibiotics and toxins.
Some of the more common antibiotics that humans use to ward off infections came originally from fungi and bacteria. Predation or parasitism. This is the mechanism most often associated with biocontrols. The biocontrol agents attack and feed directly on target organisms. Induced resistance in the host plant.