Phytotoxic effects of several essential oils on two weed species and Tomato

Essential oils (EOs) composition of Rosmarinus officinalis L., Satureja hortensis L. and Laurus nobilis were analyzed by GC and GC-MS instrument. Then phytotoxic activities of mentioned EOs and a combination of R. officinalis and L. nobilis EOs (R+L) were evaluated against germination and growth of two weeds species, A. retroflexus (dicot), B. tectorum (monocot) and tomato. Applied EOs strongly inhibited the germination and seedling growth of the tested species, in a dose dependent manner with A. retroflexus being significantly more sensitive than others. Indeed, at 400 μL.L−1 EO of R. officinalis, germination of A. retroflexus decreased 91.3%, while for the same dose, germination and seedling growth of B. tectorum and tomato were reduced by 56.7% and 26.7%, respectively, compared with control. R. officinalis EO caused the most germination inhibitory for A. retroflexus and tomato while B. tectorum germination was well inhibited by S. hortensis EO. Seedling growth were also affected by EO application in a dose response manner. A. retroflexus shoot length was inhibited by the R+L EO more than other EOs while most root growth inhibition caused by S. hortensis EO. For B. tectorum, and tomato, S. hortensis had the strongest inhibitory effect on root and shoot elongation.