Abstract
The chemical composition of essential oils isolated by hydrodistillation from needles and cones of Thuja orientalis L. was analysed by gas chromatography-flame ionisation detection and gas chromatography–mass spectrometry. Twenty-one compounds were identified; quantitative differences, mainly, between cone and needle oils were observed. Both oils were rich in monoterpene hydrocarbons and the major constituents were α-pinene (64.2 and 49.3%, respectively, in cones and needles), β-phellandrene (6.7–9.6%) and α-cedrol (3.9 and 8.2%). Herbicidal properties of Thuja essential oils were assessed against three invasive weed species in crops: Sinapis arvensis L., Phalaris paradoxa L. and Lolium rigidum Gaud. The study of herbicidal activity was carried out on the weed germination, seed vigour and seedling growth. Our results showed a strong inhibitory effect on all tested weeds following a dose-dependent manner, property that could be valourised in managing biocontrol of weeds.