ATTACHMENT MICROBES ANTAGONISTIC AGAINST BOTRYTIS-CINEREA - BIOLOGICAL-CONTROL AND SCANNING ELECTRON-MICROSCOPE STUDIES IN-VIVO

Bacteria and yeasts, selected by an attachment assay for their ability to adhere to Botrytis cinerea hyphae or conidia, were evaluated for b iocontrol potential against B. cinerea on excised tomato stems. Eight of the 12 bacteria and seven of the eight yeast isolates conferred 90% to 100% biocontrol activity when antagonist populations were applied at three to 80 times the pathogen inoculum density. Biocontrol was mai ntained at similar levels when biocontrol agent (BCA) application was delayed up to 48 h after pathogen challenge. Scanning electron microsc opy showed extensive colonisation of B. cinerea mycelium or conidia by many of these isolates and also evidence of pathogen degradation. The biocontrol efficacy and potential for the assay are discussed with re spect to cell-to-cell adhesion as a vehicle to deliver antagonistic me chanisms to highly specific pathogen sites.