Effect of oils and soaps on the efficacy of silicone films used for mosquito larval control

Aquatain AMF® is a silicon monomolecular film used for mosquito control in urban storm drains, killing the larvae reducing the surface tension and preventing them to breath. This study investigated the influence of common household substances (sunflower oil and car wash soap) often poured into the rain drains, on the efficacy of Aquatain. Simulating the rain catch basins in laboratory, the experiment evaluated the impact of these substances on Aedes albopictus larvae survival in controlled conditions. The obtained data showed that oil significantly slowed larval mortality compared to the control group, unlike soap, which had no significant effect. The potential negative impact of substances leaching into storm drains, whether accidentally or deliberately, offers a possible explanation for the reduced effectiveness of monomolecular films in larvicidal applications. The results suggest the need for public awareness campaigns to discourage the disposal of oil and other substances into storm drains and may necessitate adjustments to treatment strategies, such as increasing the frequency of applications in areas where this bad habit is particularly frequent.