repellency effects of essential oils of myrtle (myrtus communis), marigold (calendula officinalis) compared with deet against anopheles stephensi on human volunteers

background: malaria and leishmaniasis are two most significant parasitic diseases which are endemic in iran. over the past decades, interest in botanical repellents has increased as a result of safety to human. the comparative effi- cacy of essential oils of two native plants, myrtle ( myrtus communis ) and marigold ( calendula officinalis ) collected from natural habitats at southern iran was compared with deet as synthetic repellent against anopheles stephensi on human subjects under laboratory condition. m ethods:   essential oils from two species of native plants were obtained by clevenger-type water distillation. the protection time of deet, marigold and myrtle was assessed on human subject using screened cage method against an. stephensi . the effective dose of 50% essential oils of two latter species and deet were determined by modified astm method. ed50  and ed90 values and related statistical parameters were calculated by probit analysis. r esults: the protection time of 50% essential oils of marigold and myrtle were respectively 2.15 and 4.36 hours compared to 6.23 hours for deet 25%. the median effective dose (ed50) of 50% essential oils was 0.1105 and 0.6034 mg/cm2  respectively in myrtle and marigold. the figure for deet was 0.0023 mg/cm2. co n clusion: this study exhibited that the repellency of both botanical repellents was generally lower than deet as a synthetic repellent. however the 50% essential oil of myrtle showed a moderate repellency effects compared to marigold against an. stephensi .