Ovicidal, pupicidal and bactericidal effects of aminopyridinium-based ionic liquids on Culex pipiens and certain human pathogenic bacteria

Culex pipiens (Diptera: Culicidae) is one of the most prevalent mosquitoes particularly in the Al-Madinah Al-Munawwarah region, Kingdom of Saudi Arabia, transmitting numerous diseases such as arboviruses, avian malaria, elephantiasis, dirofilariasis, and encephalitis. Worldwide, Culex pipiens has developed resistance to numerous insecticides; therefore, considerable efforts have been done to introduce new mosquito control candidates. Due to their unique physical, biological, and eco-friendly properties, ionic liquids (ILs) have been recently considered as promising agents in controlling a variety of organisms. Six aminopyridinium-based ionic liquids (IL1-IL6) were assayed against eggs and pupae of C. pipiens. Percentages of non-hatched eggs, non-emerged pupae, the lethal concentrations (LC50 and LC90) of both C. pipiens eggs and pupae were recorded. after exposure, to different ILs. The effects of ILs against eggs and pupae were concentration and IL-dependant. The percentages of egg unhatchability were much higher than those of pupal mortality, as the percentage of egg unhatchability reached 99% after treatment with IL6 at 0.5 g/L, while the percentage of pupal mortality reached 40.8% after treatment with IL4 at 0.5 g/L. The LC50 and LC90 of ILs against pupae were much higher than those of ILs against eggs. Effects of ILs on Staphylococcus aureus (Bacillales: Staphylococcaceae) and Escherichia coli (Entrobacterales: Entrobacteriaceae) were also studied; some ILs showed a considerable effect on both bacteria species. This is the first study to show the ovicidal, pupicidal, and bactericidal effects of aminopyridinium-based ILs in controlling C. pipiens, S. aureus, and E. coli.