Antifungal Efficacies of Plant Essential Oils and Main Constituents Against Soil-Borne Fungal Disease Agents of Bean

Abstract

In this study, in vitro antifungal efficacies of essential oils (EO's) obtained from taxonomically different medicinal plants such as oregano (Origanum syriacum L), fennel (Foeniculum vulgare Mill.) and laurel (Laurus nobilis L.), naturally growing in the different regions of Hatay province, and their major constituents (carvacrol, trans-anethole and 1,8-cineole) were investigated against soil-borne fungal disease agents of bean plants such as Sclerotium rolfsii, Rhizoctonia solani and Macrophomina phaseolina. Inhibitory effects of volatile and contact phases of different concentrations of the essential oils used were determined on fungal hyphae. While contact phases of O. syriacum and F. vulgare EO's completely inhibited mycelial growth of fungal pathogens at 160 to 320 µg/ml concentrations, L. nobilis EO, however, completely inhibited mycelial growth at relatively higher concentrations (1440 to 2880 µg/ml). In comparison, volatile phases of all EO have completely inhibited mycelial growth at relatively lower concentrations (20 to 200 µg/ml). Major components of O. syriacum, and F. vulgare EO's, carvacrol and trans-anethole respectively, also completely inhibited mycelial growth at 130 to 440 µg/ml concentrations. Major component of L. nobilis EO, 1,8-cineole, was, however, able to show antifungal activity against only M. phaseolina at the highest concentration (3000 µg/ ml). Antimicrobial activities shown by EO's and their major constituents against fungal disease agents revealed their potential to be used as a new alternative control measures against fungal diseases of economically important plant.