In the present study, using standard test procedures, we report that relatively cheap surfactants such as vegetable oil esters or soap at 0.5 or 1% v/v mixture with neonicotinoids can selectively enhance the potency of neonicotinoids against mosquito populations. This can bias the test incase resistance is present in the tested population at a low level. From another point of view, implementing vector control tools containing neonicotinoids and relatively cheap vegetable oil soap as adjuvant, can help increase the impact of the intervention. However, this can only be done prior to proper investigation given that, results from our study equally show adding these adjuvants to pyrethroids does not significantly increase their potency. Indeed insecticide resistance is a threat to progress achieved in the fight against malaria through the use of Long-Lasting Insecticidal nets (LLINs) and Indoor Residual Spraying (IRS). In order to mitigate this phenomenon and move towards eradication, new molecules are being sorted for and their efficacy evaluated. As a result of the identification of these new chemistries, the World Health Organization (WHO) standard operating procedure for testing insecticide susceptibility in adult mosquitoes has been updated to include new active ingredients. For example, to evaluate the susceptibility to clothianidin, a neonicotinoid or to flupyradifurone, a butenolide, adult mosquitoes are not exposed to the active ingredient alone, but to a mixture containing a surfactant which helps in solubilization and enhances take up of the pesticide. Despite the recommended use of this adjuvants, few studies have been carried out to evaluate the interaction between insecticide and these compounds generally described as “inert”.
Read more: https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0011737
