Although there are many ‘natural’ mosquito repellents on the market, mostly containing citronella. Their efficacy is questionable at best and, if they work at all, it’s only for minutes, not hours as their overpowering smell temporarily disguises the scent of our bacteria-laden bodies that mosquitos find so irresistible.
The only truly proven mosquito repellent, DEET (diethyltoluamide), is a chemical concoction that can irritate many people’s skin or even cause severe reactions. Despite the potential for severe reactions, it’s much safer to use DEET than not, especially in subtropical and tropical areas as mosquito-borne diseases like yellow fever, dengue and malaria are much more deadly.
But it puts many scientists hot on the trail of discovering safer bio-pesticides.
The latest candidate is sweet grass, Hierochloe odorata, native to both the Americas and Eurasia. It has long been used by native Americans as a sacred and ceremonial plant and also in traditional medicine and it was valued for its sweet, vanilla-like scent. Native Americans wove it into braids or baskets, and also hung it in their houses.
Sweetgrass is also called bison grass in Europe, and was used to strew church floors in medieval times, although these days you’re most likely to come across it in a bottle of Polish vodka.
Scientists from the University of Mississippi’s Natural Products Utilization Research Unit have presented a paper to the American Chemical Society which describes how a steam-distilled oil made from sweet grass was just as effective at preventing mosquitos from feeding on a blood-like substance as DEET.
Possessing a double whammy of coumarin and phytol, sweetgrass holds considerable promise as a new bio-pesticide.
Lovers of Avon beauty products may remember one called ‘Skin-so-Soft’ which many users felt had an added benefit of deterring mosquitos. It contained coumarin.
Read more about the research at the American Chemical Society.