Phytotoxicity of Essential Oils on Selected Weeds: Potential Hazard on Food Crops.

The chemical composition of winter savory, peppermint, and anise essential oils, and in vitro and in vivo phytotoxic activity against weeds (, , and ) and food crops (maize, rice, and tomato), have been studied. Sixty-four compounds accounting for between 97.67⁻99.66% of the total essential oils were identified by Gas Chromatography-Mass Spectrometry analysis. Winter savory with carvacrol (43.34%) and thymol (23.20%) as the main compounds produced a total inhibitory effect against the seed germination of tested weed. Menthol (48.23%), menthone (23.33%), and -menthone (16.33%) from peppermint only showed total seed germination inhibition on , whereas no significant effects were observed with -anethole (99.46%) from anise at all concentrations (0.125⁻1 µL/mL). Low doses of peppermint essential oil could be used as a sustainable alternative to synthetic agrochemicals to control The results corroborate that in vivo assays with a commercial emulsifiable concentrate need higher doses of the essential oils to reproduce previous in vitro trials. The higher in vivo phytotoxicity of winter savory essential oil constitutes an eco-friendly and less pernicious alternative to weed control. It is possible to achieve a greater in vivo phytotoxicity if less active essential oil like peppermint is included with other active excipients.