Effect of Different Formulations of Polyphenolic Compounds Obtained from OMWW on the Growth of Several Fungal Plant and Food Borne Pathogens. Studies in vitro and in vivo
S.V. Leontopoulosa, I. Giavasis, K. Petrotos, M. Kokkora and Ch. Makridis
Department of Agricultural Engineering Technologists, Technological Educational Institute of Thessaly (T.E.I.), Larissa, 41110, Greece.
The assessment of different concentrations and forms of polyphenols (free and encapsulated) from olive mill waste (OMWW) as plant protection materials against economically important plant pathogenic fungi in in vitro and in vivo tests is the main research area of this work. In the first stage of the experimental process, it was assessed the zone of inhibition in mm of several fungal pathogens using the methods of disk diffusion assay, and well diffusion assay. In the second stage of the evaluation, the effect of polyphenols against 14 fungal microorganisms was examined in order to determine the MIC / microbicidal concentration (MIC / MFC). In a later stage in vivo evaluation of liquid polyphenols (LFP) obtained from OMWW as natural bio-chemicals against several fungal pathogens on tomato plants was carried. The evaluation of the results obtained by determining the MIC and MLC, demonstrated that the fungus Aspergillus flavus appeared highly resistant to the LFP concentration required minimum sample rate > 35-40 % for inhibition and killing effects respectively. In order of major protection resulting from the use of polyphenolic compound against major diseases, Botrytis cinerea, Sclerotinia sclerotiorum and Ascochyta lentis gave the most promising results. Moreover, the use of low concentration of LFP at 5 and 10 % could control in some cases fungal pathogens. However, higher concentration of LFP (20 and 30%) appeared possible phytotoxic effects.
Keywords: Polyphenols, Biocontrol, Plant diseases, OMWW.