Chemical composition and herbicidal potential of essential oil of Eucalyptus maculata Hook

In continuation of the search of eco-friendly and safe alternatives for chemical pesticide for weeds management, essential oils (EOs) of forestry tree may be a good candidate. Here, the EOs of Eucalyptus maculata were extracted by hydrodistillation and the study of their chemical composition was carried out by GC and GC/MS analysis. The allelopathic effects of E. maculata EOs was tested against two common weeds in Tunisia: Sinapis arvensis (dicot) and Phalaris canariensis (monocot) and Triticum durum as cereal monocot cultivated crop. The application of EOs has been carried out in two stages of growth: pre-emergence and post emergence. Analysis of the EOs resulted in the identification of 46 components representing 97.7% of the total oil. 1.8-Cineole was detected as the principal compound accounted for 42% of the oil totality and oxygenated monoterpenes (61.5%) was the major subclass that characterize E. maculata growing in Tunisia. On pre-emergence stage, Eucalyptus EOs significantly reduced germination and seedling growth of all tested species in a dose dependent manner and the phytotoxic effect of the EOs was differently effective depending on doses and tested species. On post-emergence stage, volatile oil induces a phytotoxic effect against all tested plants, a decrease in relative water content, an increase of relative electrolyte leakage percentage and levels of proline and malondialdehyde contents which explain their significant phytotoxic potential. Thus, E. maculata EOs inhibits germination and seedling growth of tested herbs in pre-emergence stage and post emergence stage, therefore E. maculata EOs shows potential towards weed management.