Essential oils as allelochemicals and their potential use as bioherbicides

Essential oils were extracted from 32 aromatic plants and evaluated for all elopathic properties. The major components of the oils were identified by g as chromatography and GC-MS. Extracts from Origanum syriacum, Micromeria fr uticosa, and Cymbopogon citratus were selected for further study. The germi nation of several species, including wheat, was strongly inhibited by essen tial oils when applied at 20-80 ppm. Essential oils mixed with the top 0.5 cm of soil inhibited germination of wheat and Amaranthus seeds. This effect depended on the type of soil. The possible use of essential oils as herbic ides is discussed.