Phytotoxic Effects of Essential Oils from Six Lamiaceae Species

Essential oils produced by plants, and their components, could be sources of new natural herbicidal compounds. Thirteen extracted from six wild Lamiaceae species (namely Clinopodium suaveolens (Sm.) Kuntze, Satureja montana L. subsp. montana, Thymbra capitata (L.) Cav., Salvia fruticosa Mill. thomasii (Lacaita) Brullo, Guglielmo, Pavone & Terrasi, cuneifolia Ten., Thymus spinulosus Ten.) South Italy were tested in vitro for the phytotoxic activity to cress branched broomrape seeds, tomato radicles, lambsquarters leaf disks. Moreover, possible correlation between oil composition biological was evaluated. One T. inhibited germination 96.4% at lowest concentration (100 ppm) reduced both chlorophyll carotenoid content disks around 50%. Some oils, particularly those spinulosus, radicle elongation 85% 1000 ppm. Many seed up 100% when solution ppm or released as vapors. Among α-terpinene, p-cymene, β-cis-ocimene, cis-sabinene hydrate, carvacrol methyl ether, thymol mostly correlated inhibition seeds elongation. The presence p-cymene also germination. essential components have potential pre-emergence herbicides useful development weed control strategies.