Abstract
Phytoncides, which are volatile substances emitted from plants for protection against plant pathogens and insects, are known to have insecticidal, antimicrobial, and antifungal activities. In contrast to their negative effects on microorganisms and insects, phytoncides have been shown to have beneficial effects on human health. Essential oil from Hinoki cypress (Chamaecyparis obtusa) is mostly used in commercial products such as air purifiers. However, the physiological/behavioral impact of essential oil from C. obtusa on insects is not established. In this study, we tested the effects of essential oil extracted from C. obtusa on the physiologies and behaviors of Drosophila melanogaster and Musca domestica. Exposure to essential oil from C. obtusa decreased the lifespan, fecundity, locomotive activity, and developmental success rate of D. melanogaster. In addition, both fruit flies and house flies showed strong repellent behavioral responses to the essential oil, with duration times of about 5 hours at 70 μg/ml. These results suggest that essential oil from C. obtusa can be used as a 'human-friendly' alternative insect repellent.