Repellency of aromatic turmeric Curcuma aromatica under laboratory and field conditions.

Three Curcuma species, Curcuma aeruginosa (pink and blue ginger), Cu. aromatica (aromatic turmeric), and Cu. xanthorrhiza (giant curcuma), were selected for investigation of mosquito repellent activity. In a laboratory study, a 95% ethanol extract of each plant was tested for repellent activity of Aedes togoi on human volunteers. Only Cu. aromatica extract showed repellency against Ae. togoi with ED50 and ED95 values of 0.061 and 1.55 mg/cm2, respectively. It also provided biting protection for 3.5 h when applied at a concentration of 25 g%. The ethanolic extract of Cu. aromatica was therefore chosen for further repellent activity under field conditions, where it had a protective effect against Armigeres subalbatus, Culex quinquefasciatus, and Cx. tritaeniorhynchus. The ethanol-extracted Cu. aromatica did not cause dermal irritation when applied to human skin. No adverse effects on human volunteers were observed 2 mo after application. Therefore, Cu. aromatica extract can be applied as an effective personal protection measure against mosquito bites.