Original Articles
Mohammad Hassan Kayedi*, Marzi
Abstract
Malaria is still one of the most important infectious diseases in the world. The main problem is that many of the Anopheles mosquitoes have become resistant to various chemical pesticides and also their resistance or tolerance to pyrethroid insecticides which used for impregnating of bed nets has been reported, so the essential oils of plants with insecticidal properties are good candidates for replacements of chemical insecticides for treating of nets. Thirty-two Polyester untreated mosquito nets were impregnated with Myrtus communis (moort) (at concentrations of 1%, 5%, 10% and 30%) and Satureja khuzestanica (karvakerol) (at concentrations of 2%, 5%, 10% and 20%) essential oils. We prepared four treated nets of each concentration. Mean median knock down time (MMKDT) in continuous exposure bioassay test and mortality 24 h after 3-minute exposure test were carried out on nets. Results showed that with increasing concentrations of Moort essential oil the time for knock down (KD) is significantly increased (P = 0.006). On the contrary, by increasing the concentration of essential oil of karvakerol, the time for (KD) is significantly reduced (P <0.001). With increasing concentrations of Moort essential oil ,there was no significant increase in mortality percentage for Anopheles stephensi (P = 0.716), whereas by increasing the concentration of karvakerol essential oil , percentage of deaths and mortality was border line increased for Anopheles stephensi (P = 0.073).