A huge amount of residues are produced in the extraction of olive oil; peel, stones and other solids. These residues contain polyphenols which prevent the propagation of bacteria and fungi. To date liquid extracts have been found effective against certain strains of Fusarium culmorum and Botrytis cinerea and further trials will include tests against Phytophthora infestans. The most important of these polyphenols is Oleuropein and in the plant it works naturally against pathogens. By freezing or heating the residues for a short period the Oleuropein breaks down into even more effective substances. Scientists hope to be able to develop a type of 'polyphenol varnish' that can be sprayed onto crops to act as an natural barrier against pathogens. AlphaGalileo For further information contact Dr. Günther Laufenberg tel 0049 228 734274, E-mail: g.laufenberg@uni-bonn.de www.uni-bonn.de