A grapefruit-scented perfume ingredient that’s toxic to ticks and mosquitoes is the first new insect repellent to be approved in a decade
- The EPA has approved a new ingredient, nootkatone, for use in insecticides and insect repellents.
- Nootkatone is effective at repelling and killing mosquitoes, ticks, and other biting pests.
- The chemical is nontoxic to humans and has been used in perfume and food for its grapefruit aroma.
- The introduction of a new insect repellent ingredient could help slow resistance to insecticides.
The Environmental Protection Agency approved a fragrant and relatively safe chemical as a defense against ticks and mosquitoes on Monday.
The chemical, nootkatone, smells and tastes like grapefruit and is naturally found in the rind of the fruit, as well as in Alaskan yellow cedar trees.
Nootkatone protects from bug bites at similar rates as insect repellents currently on the market and has a staying power of up to several hours, the Centers for Disease Control and Prevention (CDC) found. It’s the first new chemical to be approved for this purpose since 2009.
The newfound insect repellent shows promise as a protector against ticks in particular, insect toxicology expert Joal Coats told Insider. Compared to synthetic chemicals like DEET, nootkatone is equally effective at repelling mosquitos but much better at warding off ticks.
Nootkatone has superior staying power and efficacy compared to other natural repellents
While nootkatone is poisonous to insects, the chemical is nontoxic to humans and other mammals, so much so that it’s commonly used in perfumes, foods, and drinks.
Other essential oils derived from plants such as peppermint and lemongrass have been found to have some insect repellent properties but poor staying power. Those oils wear off after an hour or two, but Coats estimated that nootkatone could last up to three times longer.
Nootkatone is also more effective at killing ticks than other natural products, public health entomologist Thomas Mather told Insider. In an evaluation of minimal risk natural insecticides, he found nootkatone was 83 percent effective — comparable to the synthetic standard — while most other natural products failed.
As biting insects develop resistance to products on the market, nootkatone could offer an alternative
The introduction of a new insect repellent comes at a time when pests are developing resistance to commonly used chemicals and insect-borne diseases are on the rise.
A CDC report found in 2018 that diseases caused by ticks, mosquitoes, and fleas — such as Lyme disease, West Nile, dengue, and Zika — have tripled in the United States in the past 15 years.
Adding some variety to the arsenal of insect killers and repellents will slow the development of resistance and help the fight against insect-borne diseases.
The discovery of nootkatone takes advantage of naturally-occuring compounds that plants use to protect themselves, Coats added.
“Terpenes, or naturally compounds occurring in plants, have lots of importance from a chemical ecology perspective,” Coats said. “They’re in plants as some sort of defensive strategy to prevent insects from attacking those plants, so it’s great that we’re starting to learn how to use those more and more for our benefit.”