Essential Oils of Three Aromatic Plant Species as Natural Herbicides for Environmentally Friendly Agriculture

Abstract

Natural herbicides based on essential oils (EOs) extracted from aromatic plants are gaining relevance in contemporary agriculture. Due to their allelopathic properties, they have an inhibitory effect on the germination and growth of different species, having, in general, the advantage of high specificity. For this reason, the analysis of the effects of these natural compounds on noxious weeds is continuously increasing. In the present study, three commercial EOs extracted from Mentha piperita L., Thymbra capitata (L.) Cav. and Santolina chamaecyparissus L. were tested on two invasive weeds with an increasing presence in southern Europe, Erigeron bonariensis L. and Araujia sericifera Brot. Five concentrations (0.125, 0.25, 0.50, 1 and 2 µL mL–1) were tested in a randomized manner for each essential oil and five replicates with 20 seeds each for E. bonariensis and 10 replicates with 10 seeds each for A. sericifera. Two higher concentrations of 4 and 8 μL mL–1 of the three EOs were applied with irrigation on the plants of the two species at the vegetative growth stage. The number of replicas for each treatment and species was 7. The results obtained confirmed the significant inhibitory effects on seed germination and early seedling development, especially in E. bonariensis; of the three EOs, peppermint had the strongest effect, completely preventing germination in both species. Multivariate analysis, performed on several morphological traits scored after one month of treatment in young plants, showed a different pattern: the highest inhibition was recorded in A. sericifera and the greatest reduction in growth in the treatment with the highest dose of Santolina EO. The results obtained revealed the efficacy of these natural compounds and the specificity of their toxicity according to the species and stage of development.

Oregano essential oil and its main components Thymol and Carvacrol as alternatives to control citrus canker

“…Regarding phytotoxicity, the effects observed on seed germination and root growth were rather expected, due to the allelopathic properties of essential oils and their constituents. Described as the interspecific interaction between species, where one is able to affect the growth and development of the other through chemical substances, allelopathy plays an important role both in natural system as well as in agro-ecosystems (Aslam et al, 2016;Bellache et al, 2022). Essential oils from the genus Origanum and its main constituents, THY and CAR, have already been described as phytotoxic to commercial and weed species (Synowiec et al, 2016;Ibañez and Blaźquez, 2020).…”

Comparative Analysis of Tolerance to Salt Stress and Water Deficit in Two Invasive Weeds of the Genus Erigeron (Asteraceae)

“…Thus, knowledge of the ecology and germination of invasive plant species is essential for the development of effective weed management systems both economically and environmentally. Information on the ecology of invasive weed species, their dynamics, rates of adaptation and response to environmental factors is needed to prevent potential new invasions and mitigate the long-term impacts of invasive weed species [ 52 , 53 , 54 ].…”

Oregano essential oil and its main components Thymol and Carvacrol as alternatives to control citrus canker

“…Regarding phytotoxicity, the effects observed on seed germination and root growth were rather expected, due to the allelopathic properties of essential oils and their constituents. Described as the interspeci c interaction between species, where one is able to affect the growth and development of the other through chemical substances, allelopathy plays an important role both in natural system as well as in agroecosystems (Aslam et al 2016;Bellache et al 2022). Essential oils from the genus Origanum and its main constituents, THY and CAR, have already been described as phytotoxic to commercial and weed species (Synowiec et al 2016;Ibáñez and Blázquez 2020).…”