Repelling Bugs With The Essence Of Grapefruit Scientists are working on a new, natural bug repellent. It's non toxic, non-greasy and smells like grapefruit. For insects it's deadly but for humans it's safe enough to drink.

Repelling Bugs With The Essence Of Grapefruit

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This is MORNING EDITION from NPR News. Good morning. I'm Renee Montagne.


Today in Your Health, we'll go back to nature, foraging for nutritious wild food. But first, the search for a new, all-natural insect repellent. NPR's Richard Knox reports on the sweet smelling work being carried out by the Centers for Disease Control and Prevention.

RICHARD KNOX: Right now, the leading bug repellent is DEET. Lots of people don't like it because it has a greasy feel and a chemical smell. At the CDC's laboratories in Fort Collins, Colorado, bug expert Marc Dolan and his team have come up with a new repellent. Dolan rubs some of it on his right hand.

MARC DOLAN: It's non-greasy, dries very quickly. And it has a very pleasant, citrus-y grapefruit odor to it.

KNOX: It's an extract of the Alaska yellow cedar tree.

DOLAN: So I'm opening up the cage.

KNOX: To try it out, Dolan puts his hand into a cage that contains 50 hungry mosquitoes.

DOLAN: The ones on the wall I'm placing my hand next to and they try to get away in the opposite direction as quickly as they can.

KNOX: No mosquitoes are landing on his hand. And now he puts his other hand - unprotected by any repellent - into another mosquito cage.

DOLAN: Within a matter of seconds, I had mosquitoes feeding on my untreated hand. And I still do not have any mosquitoes on my treated hand.

KNOX: The stuff on Dolan's treated hand is called nootkatone. In addition to cedars, it's also found in grapefruit and other citrus, and in some herbs and grasses. Nootkatone is so non-toxic you could drink it. In fact, it's already an approved food additive, and a natural ingredient in some foods.

DOLAN: If you've had a grapefruit, you've consumed some nootkatone, or drank a Squirt, for instance.

KNOX: And here's a remarkable thing, nootkatone could be both a repellent and an environmentally friendly pesticide. That's because it doesn't just repel bugs. It kills them. Dolan's colleague, Nick Panella, demonstrates.

NICK PANELLA: It sounds like a mosquito, this thing.


KNOX: Panella uses a vacuum pump to transfer mosquitoes into a jar. He's coated the inside of it with nootkatone.

PANELLA: OK. I think that's enough.

KNOX: As soon as they're in the jar, the mosquitoes begin to die. Here's Marc Dolan.

DOLAN: Already in that short duration, there's only two mosquitoes - is there three left alive? This stuff has incredible knock-down, so it kills things very, very quickly, usually within a matter, depending on the concentration, in about 15 seconds.

KNOX: It kills by blocking receptors on insects' nerve cells, receptors humans don't have. It makes them hyperactive. They basically shake themselves to death.

DOLAN: Yeah, they buzz around on their back. Usually they get completely disoriented. And then eventually they keel over.

KNOX: Richard Knox, NPR News.

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