Control of Carrot Seed-Borne Pathogens by Aromatic Plants Distillates ^†

Global warming, pollution problems, and the demand for sustainable food production forced farmers and scientists to search for new solutions in biological plant protection. The usage of natural renewable sources around us seems to be an alternative. Compounds isolated from plants and distinguished with antifungal properties can be used to protect vegetables from the seed-borne pathogens. The study aimed to elucidate the ability of Juniperus communis L., Hyssopus officinalis L. and Thymus vulgaris L. essential oils to control the carrot seed-borne pathogen Alternaria spp. The agar-plate method was used for carrot seed infestation with micromycetes. Essential oils extracted from common juniper, hyssop and thyme were then separately mixed with potato dextrose agar media at different concentrations and the antifungal activity of each oil tested in vitro. The results revealed that the T. vulgaris essential oil (200–1000 μL L⁻¹) significantly inhibited Alternaria spp. growth. The H. officinalis essential oil promoted seed-borne pathogens growth on the second and fifth days of the evaluation compared to the control; however, the concentration of 400 μL L⁻¹ showed little suppression of micromycete development 7 days after inoculation. The in vitro experiments indicated that 600 μL L⁻¹ of J. communis essential oil could control seed-borne pathogen viability. Overall, thyme essential oil expressed a high potential for application in biofungicide formulations.