Biocontrol potential of essential oils from six Moroccan plants against the causal agent of Verticillium wilt of olives

Abstract

In the realm of sustainable agriculture, biocontrol is gaining considerable attention for its focus on the development of safe, biodegradable, and environmentally friendly alternatives to traditional biocides. This study explored the potential use of essential oils as alternative biocontrol products for managing Verticillium dahliae, the causal agent of Verticillium wilt in olive trees. Essential oils (EOs) were obtained through hydrodistillation from six Moroccan aromatic and medicinal plants (Ammodaucus leucotrichus, Mentha spicata, Origanum majorana, Rosmarinus officinalis, Salvia officinalis, and Thymus satureioides). These EOs were then subjected to chemical analysis by gas chromatography-mass spectrometry (GC-MS) and evaluated in vitro for their antifungal properties against V. dahliae. The bioassays revealed that all tested EOs reduced mycelial growth of the studied strain, and tended to have dose-dependent effects. Compared with the various essential oils evaluated in this study, A. leucotrichus essential oils showed the most pronounced antifungal efficacy at low and moderate concentrations. These EOs stand out for their high content of two monoterpenes, perillia aldehyde (84.19 %) and limonene (14.15 %), which were not found in the other essential oils examined. Therefore, our results open up new possibilities for exploiting these plants and their chemical constituents to develop a natural biofungicide as a component of integrated management strategies for Verticillium wilt of olive and other crops.