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Catnip puts bite on mosquitoes By David Derbyshire, Science Correspondent (Filed: 28/08/2001)

CATNIP, the herb that sends cats into a state of purring euphoria, is one of the strongest mosquito repellents known to man, a study has shown.

The nepetalactone oil that gives the plant its odour is 10 times more effective than DEET, the chemical used in commercial repellants, researchers at Iowa State University said.

Two years ago the team found that the oil also repelled cockroaches. Catnip, or catmint, is a perennial herb. It is used in tea, as a meat tenderiser and as a folk treatment for cold, cramp, migraine and fever.

It is native to Europe and was cultivated for cats by the ancient Greeks and Romans. Nine out of 10 cats respond to its smell. Some purr and rub up against it, while others become drowsy.

Dr Chris Peterson and Dr Joel Coasts from Iowa tested the plant on yellow fever mosquitoes found in Africa and America.

Groups of 20 mosquitoes were placed in a 2ft glass tube, half of which was treated with nepetalactone, the American Chemical Society was told in Chicago.

After 10 minutes, 20 to 25 per cent of the insects remained on the treated side of the tube. When the test was carried out with DEET, 40 to 45 per cent of mosquitoes remained.

-- Anonymous, August 27, 2001

Answers

I could see where if you had a couple dozen kitties plastered to your person that there wouldn't be any room for a mosquito to snack on you.

I've never seen catnip offered in oil form. Maybe a good reason to grow some more. I used to play a game with ol' Boomer. I would crush exactly one leaf, while still attached to the plant. She would find that leaf, eat it, and waddle away.

-- Anonymous, August 27, 2001


I have one catnip plant and my cats prefer the dried stuff I get from the whole foods place. After all, it's the oil that gives the plant its odor and that might be enough to keep the mozzies away. I'll have to check, see if the store has catnip oil.

I wonder if it would help to propagate some extra plants and use them to surround seating areas on the garden.

-- Anonymous, August 27, 2001


I think it reeeeeeks..but I have rubbed it on me...guess what!!! I think it WORKED!!!! better than pesticides!

-- Anonymous, August 27, 2001

But did you have cats rolling all over you? And what will this do to the constant threat hanging over Carl?

-- Anonymous, August 27, 2001

Catnip grows wild here--our yard is full of it. Anytime I've been outside, our indoor cats go crazy over my shoes. JR likes to sleep on my garden shoes and will bite if I try to take them away from him. I definitely gotta try it for mosquitos.

-- Anonymous, August 28, 2001


I must have missed something...what threat over Carl???????????? too much "kitty"????heheheheh

-- Anonymous, August 28, 2001

SAR, Carl hasn't been the same since someone posted the joke about the kitten who snagged the naked man's family jewels while he was bent over, re-starting a disposal unit under the sink. Or was it the joke about putting catnip in someone's boxers? Anyway, he's sort of sensitive about that combination of cats and goolies.

-- Anonymous, August 28, 2001

But that works out even better for us. Far more effective to be covered with repellant and to also be standing near someone who is not.

-- Anonymous, August 28, 2001

Um, wouldn't the threat be hanging under him, in that case?

LOL

-- Anonymous, August 28, 2001


Well, Barefoot, you being the guy type, would you rather have a rambunctious kitty after the jewels or a swarm of lusty insects??

-- Anonymous, August 28, 2001


here's another article i found about catnip and mosquitoes in the New Scientist.....

  Catnip's Powerful Pong Repels Mosquitoes

  28  August  01
Andrea Graves  

Mosquitoes hate the aroma of common garden catnip, new research shows. And not only are the extracts safe, they are more effective than Diethyl-m-toluamide, or DEET, the chemical used in most commercial insect repellents.

Catnip is one of several plants used in folk medicine to ward off insects, but most people turn to DEET when they want serious deterrence. Now researchers at Iowa State University, Ames, have shown that a relatively weak solution of catnip extract repels mosquitoes as effectively as a DEET solution ten times more concentrated.

To test the effect, they put groups of 20 mosquitoes in a glass tube which had filter paper in one end treated with either a catnip extract or DEET. Ten minutes later, just over half the insects remained at the end containing DEET-treated paper. In contrast, an average of only 25 per cent remained closer to paper treated with the most potent catnip compound, a monoterpene called nepetalactone.

"Essential oils of plants have huge potential for insect control", according to entomologist Joel Coats, who was part of the Iowa team. "And they are very safe for mammalian use."

The team has previously shown that nepetalactone repels flies and cockroaches. They are applying to patent the compound as a repellant, and hope to register it as a biopesticide with the US Environmental Protection Agency (EPA).

Highly Volatile

"We haven't yet tested whether it will work against mosquitoes when on human skin," says Coats. "But our results are directly relevant to repellency on things like clothing and tents."

However, the duration of the effect is crucial, according to Jose Ribeiro, a medical entomologist of the US National Institute of Health, Bethesda. "To have a smell things have to vaporise, but if they vaporise too fast the effect is lost", he explains.

DEET is known to have a long-lasting effect and Coats admits that nepetalactone is more volatile than DEET. "That is something that can be worked on in a slow-release formula", he says.

"Anything that is as good or better than DEET is welcome, because DEET has some side effects", says Ribeiro. DEET is classified as "moderately toxic" by the EPA and can harm birds, fish and aquatic invertebrates. However, the EPA believes it does not present a health concern to the general US population.



-- Anonymous, August 31, 2001

Great find, mebs. I did find a source for catnip oil but it was wildly expensive. However, if only a weak solution works, I wonder if you could just toss some leaves and water into a food processor? Must try it!

-- Anonymous, August 31, 2001

speaking of leaves and water, I wonder if putting the leaves in a potpourri thing and setting it over a candle would work, similar to a citronella candle on the patio?

-- Anonymous, August 31, 2001

So we're all agreed we will grow lots of catnip this winter so we can test different theories?

Mine is that you just need a very large plant, and when it is time, to pick a number of leaves, crush them thoroughly with your hands, and then rub the crushed leaves over desired parts. Just seems like it would be most effective if the oils are straight from the plant, rather than dried or otherwise diluted.

Now who will volunteer to find out if any of this work on black flies?

-- Anonymous, August 31, 2001


The second article says it repels flies and cockroaches, so it might do the same for blackflies. Also, I think it was the first article that said a weak solution works. I don't think I could grow it in the winter so would have to use an infusion of dried leaves. I think I'll make it as if I were making tea.

-- Anonymous, August 31, 2001


Git, don't your poor kitties deserve a house plant this winter? ;^)

-- Anonymous, August 31, 2001

I was thinking the same thing, Brooks. LOL

-- Anonymous, August 31, 2001

Oh, yeah, right, a catnip plant in the house. You know how long it would stay potted? I may as well just spread the dirt on the floor and shred the plant over it, save some time. Actually, I get very potent dried catnip from the Whole Foods place--that would probably work well. Believe it's from Frontier Herbs, who are online somewhere.

-- Anonymous, August 31, 2001

Git, my indoor catnip plants are generally ignored. It's a matter of NOT accidentally bruising any of the leaves.

-- Anonymous, August 31, 2001

Well, there is Soc, who will bite on anything, including metal, plastic, chocolate cookies, and so on. He loves Carr's wholemeal biscuits.

-- Anonymous, August 31, 2001

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