MECHANISMS INVOLVED IN THE BIOLOGICAL-CONTROL OF BOTRYTIS-CINEREA INCITED DISEASES

Mechanisms involved in the biological suppression of infection and ino culum potential of Botrytis cinerea are numerous and variable and the involvement of two or more mechanisms has been demonstrated in several systems. Reported combinations include antibiosis with enzyme degrada tion of B. cinerea cell walls; competition for nutrients followed by i nterference with pathogenicity enzymes of the pathogen or with induced resistance; and alteration of plant surface wettability combined with antibiosis. Since germinating B. cinerea conidia are dependent on the presence of nutrients, competition for nutrients is regarded as impor tant in systems where biocontrol is involved. Conidial viability and g ermination capacity are also potentially affected by the presence of a ntibiotics produced by biocontrol agents and present in the phyllosphe re. Slower in action are mechanisms involving induced resistance in th e host plant and production of hydrolytic enzymes that degrade B. cine rea cell walls. The latter has been demonstrated much more convincingl y in vitro than in the phyllosphere. Biocontrol in established lesions and reduction of sporulation on necrotic plant tissues is a means to minimize the pathogen inoculum.