Abstract

FLORES-MACIAS, Antonio et al. Chemical composition and phytotoxic potential of Eucalyptus globulus essential oil against Lactuca sativa and two herbicide-resistant weeds: Avena fatua and Amaranthus hybridus. TIP [online]. 2021, vol.24, e303.  Epub Nov 15, 2021. ISSN 1405-888X.  https://doi.org/10.22201/fesz.23958723e.2021.303.

Weed control in sustainable agriculture requires new bioherbicidal molecules to replace synthetic herbicides that have damaged the environment and generated resistance in weeds. This study was conducted to investigate the chemical composition of Eucalyptus globulus essential oil and to explore its bioherbicidal potential on the germination and radicle growth inhibition. The phytotoxic effects of E. globulus essential oil (1, 10 and 20 μL mL-1) were tested in comparison to those of the synthetic herbicide Glyphosate (1, 10 and 20 μL mL-1) in bioassays of germination and radicle growth of Lactuca sativa and the resistant weeds Avena fatua and Amaranthus hybridus. Gas Chromatography with Flame Ionization Detector and Gas Chromatography-Mass Spectroscopy analysis showed that major monoterpenes comprised 1,8-Cineole (86.94%), α-pinene (7.71%), d-limonene (2.65%), and p-cymene (1.48%). The seed germination and radicle length exhibited different degrees of inhibition in response to the concentration of E. globulus essential oil. At some concentrations, both the Glyphosate herbicide and the E. globulus essential oil demonstrated the same phytotoxicity against the resistant weeds A. fatua and A. hybridus. Essential oil bioactivity Lethal Concentration (LC50) in the majority of cases was lowest for A. hybridus, followed by A. fatua and L. sativa. Based on the results, it can be concluded that E. globulus essential oil possesses phytotoxic potential and could be explored as a bioherbicide for resistant weeds management programs.

Keywords : bioherbicide; allelochemicals; phytotoxicity; herbicide-resistant weeds.