Inhibition of Germination and Growth of Fruit and Vegetable Postharvest Pathogenic Fungi by Essential Oil Components

Abstract

Several essential oil components were studied in order to determine their fungistatic and fungicidal activity against fruit and vegetable postharvest pathogens. In vitro trials were carried out to study their inhibition activity on fungal spore germination and mycelium growth. The study deals with several monoterpenes, whether hydrocarbons or oxygenated with different functional groups (phenols, aldehydes, ketones, ethers, epoxides). The essential oil components studied included (E)-anethole, p-anisaldehyde, carvacrol, (−)-carvone, 1,8-cineole, (+)-limonene, myrcene, (±)-α-phellandrene and (±)-α-pinene. The inhibition activity of these components was examined against some of the most widespread fruit and vegetable postharvest pathogens, including Botrytis cinerea Pers., Monilinia laxa (Aderh. et Ruhl.) Honey, Mucor piriformis Fischer, Penicillium digitatum (Pers.) Sacc., Penicillium italicum Wehm., Penicillium expansum Lk. and Rhizopus stolonifer (Eheremb.) Land. Best results were obtained with carvacrol (phenol). At a concentration of 125 ppm, the growth of all pathogen mycelia tested was completely stopped through a fungicidal action, except in the case of P. italicum. At the same concentration level the inhibition of spore germination was totally against M. laxa, M. piriformis and R. stolonifer. At 62 ppm, the control of spore germination and mycelium growth was not completely achieved (except for M. piriformis spore germination). p-Anisaldehyde (aldehyde), (−)-carvone (ketone) and (E)-anethole (ether) exhibit a progressively less marked fungistatic effect. The fungistatic action of these compounds was set at concentrations between 250 and 1000 ppm depending on fungal species. 1,8-Cineole and the monoterpene hydrocarbons, tested at concentration of 1000 ppm, showed limited or no fungistatic activity.