Joint Action of Microbials for Disease Control

During the past 20 yr, more attention than ever has been given to the devel opment of biological methods to control plant diseases. Indeed, the concern for food of high quality, without residues of pesticides, and for a sustainable agri culture that will preserve the fertility of soil, and prevent the pollution of the environment, has stimulated research dealing with biological control At the same time, progress made in molecular technology has provided tools to study the modes of action of biocontrol agents. It is now possible to understand the mechanisms by which an antagonist can limit either the density or the activity of the target pathogen, and can induce resistance of the host plant. This knowledge should help to identify the environmental conditions favorable for application of biocontrol, and improve efficiency and consistency of biocontrol methods.