Abstract: Spatial repellents are fast becoming a product class that allow for rapid protection from blood-feeding arthropods because of their relative ease of use and safety to users. However, already widespread insecticide-resistant pest populations (resistant to pyrethroids, in particular) may be less susceptible to some of these products. Natural products represent a potential source of new control tools, as many of these naturally derived compounds are structurally diverse and are efficacious themselves or represent leads to better synthetic derivatives. We screened a variety of natural products in a laboratory spatial repellency assay on Aedes aegypti mosquitoes. Repellency and toxicity dose-response curves were obtained for all compounds screened, and these curves were used to compare the relative efficacy of compounds to current commercially available spatial repellents. A number of natural products were capable of producing knockdown and toxicity at 1 hr and 24 hr respectively. Overall however, they were considerably less toxic than most synthetic repellent molecules on the market today. In terms of repellency, natural products were segregated into clear categories based on their efficacy. An analysis of the physicochemical properties of the most successful chemistries was also performed. These results demonstrate the potential of using natural products as future spatial repellent products and highlight select compounds and physicochemical properties within this class, which may be the most promising for future study and development.
