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

Abstract

The chemical composition of winter savory, peppermint, and anise essential oils, and in vitro and in vivo phytotoxic activity against weeds (Portulaca oleracea, Lolium multiflorum, and Echinochloa crus-galli) 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 iso-menthone (16.33%) from peppermint only showed total seed germination inhibition on L. multiflorum, whereas no significant effects were observed with trans-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 L. multiflorum. 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.

The Inhibitory Potential of Selected Essential Oils on Fusarium spp. Growth and Mycotoxins Biosynthesis in Maize Seeds

“…However, a possible effect of EOs on seed germination should also be taken into account. Both presented results as well as literature data [67,68] indicate that some EOs may influence seed germination, which may be connected with the presence of some components with a potential phytotoxic effect. Carvone, menthol, camphor, limonene, and thymol were described as phytotoxic monoterpenes [69,70].…”

Study of Allelopathic Interaction of Essential Oils from Medicinal and Aromatic Plants on Seed Germination and Seedling Growth of Lettuce

“…Since this compound was very high in headspace analysis of P. anisum EO (90%), it is most likely to be responsible for inhibition of the seed germination. Despite this, in another study, trans-anethole had no significant effect on seed germination inhibition [38]. The differences in the results may be, in part, due to the use of different plant species in the tests: and it should be noted that lettuce seed is more sensitive to allelochemicals.…”

Chemical composition and insecticidal potential of different Origanum spp. (Lamiaceae) essential oils against four stored product pests

“…Different activities of Origanum spp. such as antioxidant (Dutra et al, 2019), cytotoxic (Coccimiglio et al, 2016), antimicrobial (Lesjak et al, 2016;Reyes-Jurado et al, 2019), anti-acetylcholinesterase (Abou-Taleb et al, 2016;Hajlaoui et al, 2016;López et al, 2018), antibacterial (da Cunha et al, 2018;Wijesundara & Rupasinghe, 2018), repellent (Govindarajan et al, 2016;La Pergola et al, 2017;Giatropoulos et al, 2018), antifungal (Vinciguerra et al, 2018), allelopathic (Boukaew et al, 2017), phytotoxic (Ibáñez & Blázquez, 2018;Grul'ová et al, 2019) insecticidal (Kim et al, 2016;Szczepanik et al, 2018;Benelli et al, 2019) have been determined in a number of studies.…”