Essential Oils from Vietnamese Asteraceae for Environmentally Friendly Control of Aedes Mosquitoes.

Mosquitoes, in addition to being a biting nuisance, are vectors of several pathogenic viruses and parasites. As a continuation of our work identifying abundant and/or invasive plant species in Vietnam for use as ecologically friendly pesticidal agents, we obtained the essential oils of Blumea lacera , Blumea sinuata , Emilia sonchifolia , Parthenium hysterophorus , and Sphaeranthus africanus ; analyzed the essential oils using gas chromatographic techniques; and screened the essential oils for mosquito larvicidal activity against Aedes aegypti and Aedes albopictus . The most active larvicidal essential oils were B. sinuata , which was rich in thymohydroquinone dimethyl ether (29.4%), ( E )-β-caryophyllene (19.7%), α-pinene (8.8%), germacrene D (7.8%), and α-humulene (4.3%), (24-h LC 50 23.4 and 29.1 μg/mL) on Ae. aegypti and Ae. albopictus , respectively, and Emilia sonchifolia , dominated by 1-undecene (41.9%) and germacrene D (11.0%), (24-h LC 50 30.1 and 29.6 μg/mL) on the two mosquito species. The essential oils of P. hysterophorus and S. africanus were also active against mosquito larvae. Notably, B. sinuata , P. hysterophorus , and S. africanus essential oils were not toxic to the non-target water bug, Diplonychus rusticus . However, E. sonchifolia essential oil showed insecticidal activity (24-h LC 50 48.1 μg/mL) on D. rusticus . Based on these results, B. sinuata , P. hysterophorus , and S. africanus essential oils appear promising for further investigations.