Larvicidal and repellent activity of essential oils from wild and cultivated Ruta chalepensis L. (Rutaceae) against Aedes albopictus Skuse (Diptera: Culicidae), an arbovirus vector

Rutaceae are widely recognized for their toxic and repellent activity exerted against mosquitoes. In our research, the essential oils extracted from fresh leaves of wild and cultivated plants of Ruta chalepensis L. (Rutaceae) were evaluated for larvicidal and repellent activity against the Asian tiger mosquito, Aedes albopictus Skuse (Diptera: Culicidae), currently the most invasive mosquito worldwide. In this research, gas chromatography and gas chromatography–mass spectrometry analyses of the essential oils from wild and cultivated plants showed only quantitative differences, in particular relatively to the amounts of ketone derivatives, while the qualitative profile evidenced a similar chemical composition. Both essential oils from wild and cultivated R. chalepensis plants were able to exert a very good toxic activity against A. albopictus larvae (wild plants, LC₅₀?=?35.66 ppm; cultivated plants, LC₅₀?=?33.18 ppm), and mortality was dosage dependent. These data are the first evidence of the toxicity of R. chalepensis against mosquitoes. Furthermore, the R. chalepensis essential oil from wild plants was an effective repellent against A. albopictus, also at lower dosages: RD₅₀ was 0.000215 μL/cm² of skin, while RD₉₀ was 0.007613 μL/cm². Our results clearly evidenced that the larvicidal and repellent activity of R. chalepensis essential oil could be used for the development of new and safer products against the Asian tiger mosquito.