Attraction of Forcipomyia taiwana by visible light and anti-larvae activity of essential oil from indigenous plant in Taiwan

Forcipomyia taiwana is a diurnal, tiny, blood-sucking midge that solely feeds on human and distributes island-wide in Taiwan. Individuals expose to midge bites will develop intense pruritus and swelling immediately or delayed allergic responses. Therefore, preventing nuisance of biting midges by trapping adults and eliminating larvae is important. This study intended to develop a light-based attraction tool for baiting adults of F. taiwana. The results suggested that full spectrum of fluorescent lamp with low color temperature (24W; 2700K) as well as blue light (400~450 nm) attracted three times more F. taiwana than UV light in a small scale experiment. Collected F. taiwana was maintained using a newly developed mice-based feeding system in the laboratory. Reared larvae were tested for anti-larvae activities. Five crude essential oils from leaves of indigenous plants were applied. The essential oils were extracted by water distillation. The results showed that essential oils from Cinnamomun osmophloeum, Clausena excavate, and Gaultheria cumingiana completely suppressed larvae activities with a concentration of 31.6 mg/cm². Essential oils from Cryptomeria japonica and C. brevipedunculatum showed a weaker suppression with 20% of larvae survived. Our research focused on exploring sustainable, feasible, and Eco-friendly strategies for pest control. The optimal light trap would not only improve efficiency but also enhance capturing specificity. Moreover, this is the first study illustrating essential oil against midge larvae. Our investigation proposed a promising measure managing midge adults along with larvae. Practical application is being verified in the field.