139 - 142 Repellency of volatile

Volatile oils extracted by steam distillation from leaves of two plant species Moschosma polystachyum and Solanum xanthocarpum were evaluated in mosquito cages for their topical repellency effects against filarial vector Culex quinquefasciatus. The oil from M. polystachyum was tested at four different concentrations ranging from 1 to 4%. The 4% concentration gave 332.2 minutes protection whereas control gave only 4.4 minutes protection against mosquito bites. However, the volatile oil of S.xanthocarpum was tested from 2 to 8% concentration. The 8% concentration gave 311.4 minutes protection whereas control gave only 4.4 minutes protection against mosquito bites. The results suggest that the volatile oils of these two plant species were effective as repellents and gave more than 300 minutes of (>5 hour) protection against the bite of Cx. quinquefasciatus bite. Both volatile oils did not cause dermal irritation when applied to human skin. No adverse effects on human volunteers were observed after application. Therefore, both volatile oils can be applied as an effective personal protection measure against mosquito bites.