Adulticidal and repellent activities of traditionally used Ethiopian plants against Anopheles arabiensis and Aedes aegypti

Abstract

Abstract Background The widespread development of synthetic insecticide-resistant vectors threatens the effectiveness of malaria and arboviral disease control programs. Plant-derived bioactive compounds represent potential alternatives or complements for mosquito vector management. Objective Adulticidal and repellent activities of crude methanol extracts and essential oils from selected Ethiopian medicinal plants against Anopheles arabiensis and Aedes aegypti were evaluated. Methods Crude methanolic extracts and essential oils from selected Ethiopian medicinal plants were evaluated for their adulticidal and repellent activities against Anopheles arabiensis (An. Arabiensis) and Aedes aegypti (Ae. Aegypti). The insecticidal activity of the crude extracts was tested at concentrations ranging from 13.16 to 52.63 mg/L after 24 h of exposure. Mortality concentration was compared using one-way ANOVA, and the LC₅₀/LC₉₀ ratio was estimated using probit analysis. The repellent efficacy of essential oils (2.5–10%) was assessed via an arm-in-cage method, with percent repellency, complete protection time, and protection duration analyzed via Kaplan–Meier survival analysis. Result Extracts of Agave sisalana and Momordica foetida induced 80% and 79% mortality in An. arabiensis at 52.63 mg/L (LC₅₀ = 21.8 and 15.3 mg/L, respectively). Securidaca longepedunculata and Millettia ferruginea exhibit moderate adulticidal activity against Ae. aegypti, with mortality rates of up to 82% and 71%, respectively, at the highest tested concentrations. During brief exposures, essential oils from Ficus thonningii, Securidaca longepedunculata, and Momordica foetida suppressed mosquito bites by up to 79%, 86%, and 80%, respectively, although complete protection lasted only 7 min. Dose–response curves for the most active extracts were statistically significant (p < 0.05). Conclusion Crude methanol extracts of Agave sisalana, Momordica foetida, Securidaca longepedunculata, and Millettia ferruginea exhibit potent adulticidal effects against An. arabiensis and Ae. aegypti. The essential oils from Ficus thonningii, Momordica foetida, and Securidaca longepedunculata provided short-term repellency. These plant-derived products hold promise as eco-friendly alternatives for mosquito control in Ethiopia, necessitating further studies on their bioactive compounds, formulations, safety, and field efficacy.