Chemical Composition and Antifungal Activities of the Essential Oils of Thymus Species ( Thymus pectinatus, Thymus convolutus, Thymus vulgaris ) Against Plant Pathogens

Abstract

The use of herbal extracts can be considered as an alternative method to minimize the effects of synthetic chemical pesticide used to control plant pathogens on human and environmental health. The essential oils (EOs) obtained from Thymus pectinatus (TP), Thymus convolutus (TC), and Thymus vulgaris (TV) by hydrodistillation were analyzed by GC/MS. The main components of TP, TC, and TV were thymol (52.2%), p-cymene (17.03%), eucalyptol (24.47%), camphor (16.84%), α-pinene (12.88%), and carvacrol (72.47%). The antifungal activity of EOs against plant pathogens including Fusarium oxysporum f. sp radicis-Iycopersici (FORL), Phytophthora infestans, and Rhizoctonia solani was evaluated by using the agar dilution method. The EOs of TV and TP inhibited mycelium growth 100 % in FORL P. infestans, and R. solani at 4 μL/petri dose.The EOs of TC did not affect mycelial growth of R. solani and R. infestans while the mycelial growth of FORL was inhibited by 36.11%. Our findings suggested the use of these essential oils can prevent fungal infections on plants as alternatives to synthetic ones