ACTIVITY OF THYME ESSENTIAL OILS AGAINST PLANT PATHOGENIC FUNGI AND ITS POTENTIAL USE AS SEED DISINFECTANT

One potential application of essential oils as low-risk biopesticides is as seeds disinfectant. The main goal of this study was to test the activity of thyme essential oil on four strains of seed/soilborne plant pathogenic fungi, Fusarium graminearum, Botrytis allii, Rhizoctonia solani, and Pythium ultimum, and to evaluate the effect of the inhibitory doses on plant seed germination. The direct application of thyme essential oil on seeds demonstrates a lack of selectivity. The main effects were related to radicle architecture and development of the primary and lateral roots, both in monocotyl, sorghum (Sorghum saccharatum), and in the dicotyls garden cress (Lepidium sativum) and white mustard (Sinapis alba). One potential solution to the lack of selectivity of direct application of the essential oils is biofumigation, i.e., application by volatilization in the rhizosphere area. Our paper raises this issue of compatibility between the necessary doses to inhibit the plant pathogenic fungi and the effects on plant seeds. Formulation of essential oils as slow-release nanoformulation could reduce phytotoxicity while maintaining and even enhancing the activity against plant pathogens.