Co-Intercalation of Insecticides with Hexadecyltrimethylammonium Chloride in Mozambican Bentonite

Abstract

WHO-approved insecticides were co-intercalated with hexadecyl-trimethylammonium (HDTMA) chloride in bentonite in an attempt to improve their persistence. XRD and FT-IR confirmed successful co-intercalation of the insecticides. Bioassays revealed that the activity of co-intercalated insecticides deteriorated after just one week of accelerated aging at 40 °C and 90 % ℜH. However, when the pH of the bentonite slurry used for intercalation was reduced with acetic acid to pH = 4.5, the persistence life increased to 113 days. The performance ranking with respect to both knockdown and mortality was as follows: Co-intercalated α-cypermethrin > cointercalated propoxur > co-intercalated DDT > DDT.

Sustainable malaria control: transdisciplinary approaches for translational applications

“…Alternatively, durable insecticide-treated wall linings (ITWLs), a recent product concept that combines aspects of LLINs and IRS, promise long-lasting residual efficacy, negating the need for repeated annual wall treatments as currently occurs with IRS. In combination with newly identified suitable insecticide alternatives using slow-release formulations [62,63], ITWL can be used as a substitute for IRS, since it allows protective containment of the insecticide in a polymer, resulting in a longer residual efficacy. Additionally, natural insecticides including permethrin or pyrethrin and essential oils such as thymoquinone, nootkatone and carvacol [32] should be explored if their residual period of use could be increased [33].…”