Abstract
Mosquitoes (Diptera: Culicidae) are the primary vectors of several serious diseases that affect both animals and humans. Most of these diseases, especially the ones that are caused by arboviruses such as Zika, dengue and Japanese encephalitis, cannot be effectively prevented or treated, thereby rendering the discovery of alternative measures for the control of mosquito-borne diseases an absolute necessity. The current study evaluates the acute toxicity of Amomum subulatum-derived essential oil against Anopheles subpictus, Aedes albopictus, and Culex tritaeniorhynchus. We used gas chromatography–mass spectroscopy to analyze the chemical composition of A. subulatum EO. Analysis revealed thirty-three components. Primary constituents were 1,8- cineole (39.8%) and α-terpineol (11.5%). The essential oil from A. subulatum demonstrated a significant toxic effect against An. subpictus, Ae. albopictus and Cx. tritaeniorhynchus third instar larvae, with LC50 values of 41.25, 44.11 and 48.12 μg/ml and LC90 values of 80.29, 85.6 and 89.30 μg/ml, respectively. Concerning non-target effects in the aquatic environment, we evaluated the acute toxicity of A. subulatum oil on 4 mosquito biocontrol agents, Anisops bouvieri, Diplonychus indicus, Poecilia reticulata and Gambusia affinis. We observed that the toxicity of this oil was extremely low, with LC50 ranging between 3123 and 9104 μg/ml. In conclusion, the A. subulatum essential oil is an interesting bioresource to develop environmental friendly mosquito larvicides. Indeed, it is effective against different Culicidae species with LC50 always lower than 50 μg/ml, while LC50 calculated for non-target organisms are about 100-fold higher.
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•The larvicidal activity of Amomum subulatum essential oil (EO) was evaluated on 3 mosquito vectors.•The chemical composition of the EO was studied by GC and GC–MS.•1,8- cineole and α-terpineol were the major EO constituents.•EO showed larvicidal potential on An. subpictus, Ae. albopictus and Cx. tritaeniorhynchus.•Little EO toxicity rates were calculated on four non-target mosquito predators.