Rosemary and thyme usually make people think of roast chicken or lamb chops—or possibly the Simon and Garfunkel song Scarborough Fair—but innovative research from scientists at the University of British Columbia’s Faculty of Land and Food Systems could give new meaning to these common herbs. In a study presented this past weekend at a meeting of the American Chemical Society in Washington, D.C., scientists showed that essential oils from common herbs and spices can be used as effective pesticides and insect repellents.
“Killer spices,” as the researchers have dubbed them, have been shown to effectively fend off pests such as mites or aphids, and are actually already in use on some farms, protecting organic strawberry and tomato crops, for example. Essential oils from herbs and spices aren’t likely to replace chemical pesticides completely—the oils tend to evaporate quickly and need to be reapplied much more frequently than other pesticides, and they also aren’t as effective as other methods in protecting against big insects such as caterpillars or beetles. But these natural pesticides do have their advantages. For one, a greater use of natural repellents would mean less exposure to harmful chemicals for farm workers. And, whereas bugs can build up resistance to chemical insecticides, scientists say that is more complicated, and less likely, with natural oils.
Even if these potent oils don’t completely upend agricultural use of chemical pesticides, at the very least they may provide an alternative for farmers trying to protect their plants. With continued research, scientists also hope to improve both longevity and efficacy of natural repellents. And use of these “killer spices” isn’t necessarily limited to industrial farms, they say. The herb-based oils have been shown to ward off common household nuisances such as mosquitoes and cockroaches, and many products for household use are already on the market. (EcoSMART, a company that specializes in “safe pesticides,” helped fund this particular study.) Wouldn’t it be nice if, instead of the nostril-stinging scent of bug spray or the noxious fumes of household pesticides, the only sign that you were battling bugs was a slight aroma of mint?