Herbicidal, fumigant and insecticidal potential of essential oil from flowers of buddleja alternifolia maxim

Abstract

We investigated the chemical composition, herbicidal and fumigant insecticidal activities of essential oil from the flowers of Buddleja alternifolia Maxim. The main constituents of the oil were: ketoisophorone (21.89 %), (Z, E)-Geranyl linalool (3.61 %), dihydrooxoiso-phorone (7.76 %), p-vinyl guaiacol (5.15 %), phenethyl alcohol (3.40 %), safranal (3.25 %) and pentacosane (3.23 %). The fumigant insecticidal activity was investigated by exposing the 7-day-old adults of Callosobruchus maculatus and Sitophilus oryzae for 24 h at 20 to 320 μL/L air oil concentrations. The concentrations < 20 μL/L air were also assayed to interpolate the lethal concentration of 50 % (LC50). The herbicidal effects of essential oil were evaluated on seed germination and seedling growth of 4-weeds [Bidens pilosa, Lolium perenne L., Echinochloa crusgalli (L.) Beauv. and Plantago asiatica L.]. The lowest concentrations of oil causing 100 % mortality of C. maculatus were 20 μL/L and S. oryzae 40 μL/L, after exposure times of 21 h and 18 h, respectively. The susceptibility of these insects was same at concentrations < 20 μL/L with LC50 values of 9.97-12.03 μL/L. The oil at 0.08 % concentration, completely inhibited (100 % Inhibition) the seed germination of 4-test weed species. Its phytotoxic effects on the seedling growth were species specific and B. pilosa proved most sensitive weed. Hence, the flower oil may be developed as herbicide or insecticide after more research.