Suppressive activity and eco-physiological effects of composted olive by-products on the Verticillium dahliae-Oleaeurpaea pathosystem [electronic resource].

Includes references.

Olive oil by-products composted in a pilot scale in Molise (Italy) were assayed in vitro for their suppressivenessagainst various plant pathogens. Composts markedly reduced the growth of Verticilliumdahliae and other fungal pathogens and were further evaluated on various vegetal crops. On pot-grown olive plants va·ious concentrations of mature cured compost were mixed with sterile orchard soil. Mixtures were artificially ·contaminated with va'Fious concentration ofV. dahliaemicrosclerotia (MS). Periodically V. dahliae MS density in the rhizosphere, disease severity on plant canopy and plant ecophysiological response were assessed. In the rhizosphere of plants contaminated with 30 MS per g of soil 15% of the cured compost, alone or in combination with the antagonist fungus Trichodermaviridae, significantly reduced MS density; moreover, eco-physiological measurements showed no difference from control plants grown on sterile soil. Contents of compost higher than 30% showed some negative effects on plant growth, increasing also their mortality compared to plants-grown on 15% compost and/or T. viridae or100% sterile orchard soil. Elevated densities of V. dahliae MS in the rhizosphere affected gas exchange negatively. Overaii, photochemical efficiency was not affected by treatments in any case. The results pointed out that composted olive byproducts have a good potential for their re-use in organic and integrated agriculture systems as suppressive amenders if mixed with other substrates.

Summary in Arabic.

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