Efficacy of Origanum vulgare essential oil and carvacrol against the housefly, Musca domestica L. (Diptera: Muscidae)

The toxicity of Origanum vulgare essential oil to the housefly Musca domestica L. was evaluated. The major constituents of the O. vulgare essential oil by gas chromatographic mass spectrometry (GC-MS) analysis were carvacrol (58.13%), p-cymene (17.85%), thymol (8.15%), gamma-terpinene (4.96%), and linalool (3.69%). Toxicity of O. vulgare essential oil against larvae and pupae was evaluated using fumigation and contact assays. The contact toxicity (LC50) of O. vulgare essential oil and carvacrol for larvae was 0.23 and 0.03 mu L/cm(2), respectively. The fumigation toxicity (LC50) of O. vulgare essential oil and carvacrol for larvae was 9.52 and 2.78 mu L/L, respectively. Pupal toxicity was evaluated by percentage inhibition rate (PIR). PIR of O. vulgare essential oil at 0.25 mu L/cm(2) was 90.9% for the contact assay and 100% at 20 mu L/L for the fumigation assay. PIR of carvacrol was 29.5% (0.025 mu L/cm(2)) and 81.8% (1.25 mu L/L) for the contact toxicity and fumigation assay, respectively. O. vulgare essential oil and carvacrol have significant toxicity to the housefly and are potential insecticides for housefly control.