Insecticidal Activities ofOcimum canum Sims Essential Oil on Termites Macrotermes subhyalinus Rambur (Isoptera: Termitidae)

Abstract

:The essential oil from the aerial parts of Ocimum canum grown in Togo was extracted by steam distillation. An analysis using Gas Chromatography (GC) and Gas Chromatography-Mass spectrometry (GC-MS) was carried to determine the oil percentage composition and to investigate its in vitro anti-termite activity by inhalation method. The extracted oil contained mainly terpineol-4 (39.40 %), linalool (23.80 %), γ-terpinene (6.70 %), (E)-α-bergamotene (6.20 %) and β-caryophyllene (5.30 %). The in vitro anti-termite activity of the volatile oil and its major components revealed an insecticidal activities on the termite species Macrotermes subhyalinus. At 1 µ.L-1 concentration the extracted oil caused a 100 % mortality of all individuals after 24 hours of exposure. The concentrations of 0.6 and 0.8 µl.L-1 respectively. Terpineol-4 and linalool also caused 100 % mortality after an exposure time of 24 hours. To compare with the commercial pesticide (Dursban) used as positive standard control, just a concentration of 0.6 µl.L-1 was necessary to kill 100 % of the tested termites after an exposure time of 24 hours. Terpineol-4 presented the weakest LD of 0.0628 µl.L-1 compared to Dursban:0.2472 µl.L-1; linalool: 0.2993 µl.L-1 and O. canum oil: 0.4004 µl.L-1. These findings indicated that the tested essential oil and its major components are a potential anti-termite alternatives to synthetic chemical pesticide in the termite control.