University of Texas at El Paso scientists Colince Kamdem and Caroline Fouet have found that adding small quantities of liquid soap to some classes of pesticides can boost their potency by more than 10-fold. Credit: University of Texas at El Paso
Key points:
- Scientists discovered that adding small quantities of liquid soap to neonicotinoid insecticides boosted their potency by more than ten-fold.
- Researchers achieved potency increases by adding low-cost linseed-oil based soaps, meaning their strategy is an accessible option for targeting malaria-carrying mosquitoes.
- With additional testing, the team hopes to develop a soap-insecticide formulation that can be used both indoors and on mosquito nets.
A new study, published in PLOS Neglected Tropical Diseases, reveals that adding small quantities of liquid soap to some classes of pesticides can boost their potency by more than 10-fold. This finding may help target malaria-carrying mosquitoes that are becoming more resistant to current insecticides.
“Over the past two decades, mosquitoes have become strongly resistant to most insecticides,” said lead author Colince Kamdem, professor at University of Texas at El Paso. “It’s a race now to develop alternative compounds with new modes of action.”
In previous laboratory tests and field trials, neonicotinoids—a special class of insecticide—were a promising alternative to target populations that show resistance to existing insecticides. However, neonicotinoids do not kill some mosquito species unless their potency is boosted.
In this study, researchers boosted potency with soap. They tested three low-cost, linseed-oil based soaps that are prevalent in sub-Saharan Africa – Maître Savon de Marseille, Carolin Savon Noir, and La Perdrix Savon. These soaps were added to four different neonicotinoids, including acetamiprid, clothianidin, imidacloprid, and thiamethoxam.
All combinations drastically increased potency from 30 percent to 100 percent compared to insecticides on their own. Conversely, when the team tested the addition of soap to a different insecticide class known as pyrethroids, they saw no benefits.
In the future, researchers hope to conduct additional testing to determine exactly how much soap is needed to enhance insecticides. These developments could lead to a safe and accessible insecticide to fight against malaria-carrying mosquitoes.
“We would love to make a soap-insecticide formulation that can be used indoors in Africa and be healthy for users,” explained Kamdem. “There are unknowns as to whether such a formulation will stick to materials like mosquito nets, but the challenge is both promising and very exciting.”