LAUSR

Abstract Ailanthus altissima (Mill.) Swingle, tree of heaven, is an exotic tree introduced as a horticultural tree in Europe and America in 18th Century. Now it is aggressively invading ecosystems. This study was aimed to estimate phytotoxic potential of essential oils (EOs) from fourteen industrial, aromatic and medicinal crops, such as Thymus sp., Pinus sp., Origanum sp. etc. against this invasive species. The phytotoxic potential was assessed through three different doses of EOs by a germination bioassay and the effects on seedling growth. Analysis of seedling growth revealed that seven EOs (Petasites hybridus, Thymus serpyllum, Thymus vulgaris, Rosmarinus officinalis, Helichrysum italicum, Matricaria chamomilla, Origanum vulgare) exhibit high phytotoxic effect resulting in 95–100% seedling mortality. Moreover, detailed GC-MS analysis of these oils showed that they are mostly comprised either of oxygenated monoterpenes or sesquiterpene hydrocarbons, which are already known as compounds with allelopathic effects. Presented results indicate these essential oils might be used as natural herbicides by foliar application of oils on young plants of Ailanthus altissima.