Potential Synergistic Action of Liquid Olive Fruit Polyphenol Extract with Aqueous Extracts of Solid Wastes of Pomegranate or/and Orange Juice Industry as Organic Phyto-protective Agents against Important Plant Pathogens - Part 1 (in vitro Studies)

In this research study potential synergistic action of aqueous extracts of olive-pomegranate-orange fruits isolated by microwave assisted extraction were investigated as biocontrol agents against several plant pathogenic fungi. The aim of the research study was the production of mixed liquid extracts to be used as natural phytoprotective agents in organic farming. The results proved that the use of 100%-pure olive fruit polyphenol extract affected the mycelium growth of B. cinerea, V. dahliae, R. solani, E. lata, M. laxa, P. lycopersici and P. punicae. However, it did not affect the mycelium growth of F. oxysporum f. sp., lycopersici, A. niger, and G. graminis. Moreover, pomegranate polyphenol extract at 100% concentration inhibited mycelium growth of B. cinerea. Various olive-pomegranate-orange polyphenol aqueous extract combinations may be used in order to control the mycelium growth of the majority of the tested microorganisms. However, the use of any combination and concentrations of the tested samples (1-72) did not affect the mycelium growth of F. oxysporum f. sp., lycopersici, A. niger, and G. graminis thus, their use as biological control agent is not recommended. According to the findings of the present research, it can be suggested that the olive fruit polyphenol extract be used as potential biocontrol agent, in order to stimulate mycelium growth of various plant pathogenic fungi.