Effectiveness of Herbal Essential Oils as Single and Combined Repellents against Aedes aegypti, Anopheles dirus and Culex quinquefasciatus (Diptera: Culicidae)

SIMPLE SUMMARY: The repellent efficacy of ten essential oils was measured against all three-mosquito species using the arm-in-cage approach to determine the duration of protection. All essential oils showed high complete-protection time against Culex quinquefasciatus, ranging from 120 to 360 min. Petitgrain oil showed the highest complete-protection time from bites of Aedes aegypti for 270 min. Peppermint oil also exhibited complete-protection time from bites of Anopheles dirus for 180 min. When two highly effective essential oils were combined to potentially prolong mosquito bite protection, the binary combinations of petitgrain with other essential oils (basil and coriander) exhibited antagonistic effects and provided complete protection against A. aegypti bite for 150 min. On the other hand, the sage and patchouli oil combination showed more repellent activity from A. dirus bite for 270 min than an individual oil. The binary combination efficiently increased or decreased protection time. ABSTRACT: Mosquito repellents reduce human-vector contact of vector-borne diseases. We compared the repellent activity of 10 undiluted essential oils (anise, basil, bergamot, coriander, patchouli, peppermint, petitgrain, rosemary, sage and vetiver) against A. aegypti, A. dirus and C. quinquefasciatus using the arm-in-cage method. Petitgrain oil was the most effective against A. aegypti (270 min). Peppermint oil was the most effective against A. dirus (180 min). Interestingly, all single oils had attributes of repellency against C. quinquefasciatus (ranged, 120–360 min). Moreover, we integrated their binary combinations of highly effective essential oils against A. aegypti and A. dirus to potentially increase the protection time. A 1:1 combination of petitgrain/basil, petitgrain/coriander, basil/coriander and basil/sage reduced the median complete-protection time of 150 min for A. aegypti; a combination of sage and patchouli oils prolonged the median complete-protection time of 270 min for A. dirus. Combining essential oils effect protection time from these two mosquito species.