I'm going to ask a dumb question. So, get ready.

I have always brought repellent wipes. How exactly do you use a mini dropper of Deet?

Dab it on like cologne? That doesn't seem very effective.

Dilute it in water and apply? Seems more reasonable.

Just curious :-P

Thanks.

First of all, I don't think that DEET will dissolve in water, so forget that.

DEET liquid doesn't do much except when you vaporize it with body heat. You can put it directly on your skin to do that, but some people worry about toxicity. I tend to use it on clothing parts that get lots of body warmth. For example, I dab it around my shirt collar, shirt cuffs, and shirt armpits. Sometimes I dab it on my hat. That should make a mild fog of the vapor that bugs don't like.

There are some half-ounce spray containers of DEET, I find those pretty handy. You can get it on your clothing better.

If I got a drop of DEET on my skin, I would not worry about it. But I prefer to get it on my clothing, instead.

On the other hand, I've heard that it makes a dandy salad dressing. Not.

--B.G.--

Interesting. Not the response I thought I was going to get!

I had no idea that people were afraid of DEET toxicity and/or the function of the evaporation of DEET. To be honest, I've never put too much thought into it anyway!

Anyway, so it's the evaporative-cloud that prevents bugs from getting you? I figured the spray adhered to your skin and simply created a mild irritant/repellent to any bugs landing on or near you.

Thanks.

It's the cloud, but there are at least two different theories about how it works. One is that it is repulsive. Another is that it makes you smell invisible.

Will you be using permithrin too?

"Anyway, so it's the evaporative-cloud that prevents bugs from getting you?"

I just did some investigating out on the web as to how DEET works. The consensus is that it blocks receptors on the female mosquito's antennnae that detect CO2 and lactic acid, two compounds that your body produces which the mosquito uses to home in on you. Apparently no one knows for sure how it works for all insects that it repels, or even all mosquitos. Research is ongoing.

There are other pesky bugs besides the mosquito.

In Alaska, the worst ones were the biting flies, nicknamed "White Sox." The mosquito was inconsequential by comparison.

Repellant chemicals might work one way on one species and not on another, and the bugs aren't saying.

--B.G.--

6 drops -- that's all you need. The stuff actually feels a bit greasy and spreads pretty well. A little goes a long way. Two apps per day.

Referencing the "evaporative cloud" theory above -- you do not need to cover every inch of your skin for the stuff to work.

Not an expert, but to my experience, DEET doesn't kill or repel anything outright, but serves to "mask away" your scent, making you "invisible" to skeeters. Of course, when the sky is thick with skeeters, some will bump into you no matter how much DEET you apply.

Mr. Tang,

Did you have to get a special mini bottle to avoid having the deet dissolve the plastic?

acronym 8/11/2010 12:32 AM

Acronym:

These ones work very well.

Somewhere around here I have a green squeeze bottle of military-issue DEET, which I think was 95%. It dates back to the early 1970's, and the ordinary plastic bottle is perfect except for the printing, which is entirely dissolved and gone.

--B.G.--

I vote for repellant over masking.

Many times I have watched mosquitos zooming toward me and then veer away on account of the DEET. I have attributed this behavior to a "repellant" characteristic of DEET rather than a "masking" feature. Could be I'm just imagining.

Also, in the southwest, there are biting gnats about the size of a pinhead that float about in clouds, and can be very thick in places. When they bite you, they look like a fleck of black dirt on your skin. In the old days, I typically wore a felt stetson when backpacking (great hat). I have clear memories of the gnats lining up on the edge of the brim of my hat like birds on a wire. Occasionally, one would make the attempt to crawl from the brim toward my DEET protected forehead, and be turned back. I attributed this behavior to the "repellant" characteristic of DEET.

"First of all, I don't think that DEET will dissolve in water, so forget that."
It's true that it doesn't dissolve in water, but it can still be diluted with water immediately before you apply it. It forms an emulsion, not a solution, but that doesn't matter. The motivation for diluting it is that you get more mileage from the same pack-weight of 100% DEET. The down-side is that it has to be applied more frequently. To me, the convenience of not having to re-apply it all day outweighs the slight reduction in pack weight. People who use the technique typically squeeze a little deet into their palm, add some water, mix with a finger, and then apply it. Some people use a fold-top baggie instead of their palm.

Personally, what I do is to squeeze a drop of 100% DEET on the back of my hand, then use the back of my hand to rub it on the area where I'm applying it. All I normally apply it to is my head and the backs of my hands, and that only takes maybe four or six drops.

"I just did some investigating out on the web as to how DEET works. The consensus is that it blocks receptors on the female mosquito's antennnae that detect CO2 and lactic acid, two compounds that your body produces which the mosquito uses to home in on you. Apparently no one knows for sure how it works for all insects that it repels, or even all mosquitos. Research is ongoing."
How old are your sources of information? This 2008 paper contradicts what you're saying: http://entomology.ucdavis.edu/news/DEETresearch.html , Zainulabeuddin Syed and Walter S. Leal, "Mosquitoes smell and avoid the insect repellent DEET," PNAS.org

DEET dissolves polystyrene, ABS resin, styrofoam, most synthetic fabrics, and polycarbonate. This includes bear canisters and the materials used in a lot of steering wheels.

It won't harm nylon, silnylon, or polyethylene plastics.

Edited by bcrowell on 08/11/2010 08:55:05 MDT.

"How old are your sources of information? This 2008 paper contradicts what you're saying: http://entomology.ucdavis.edu/news/DEETresearch.html , Zainulabeuddin Syed and Walter S. Leal, "Mosquitoes smell and avoid the insect repellent DEET," PNAS.org"

Hmmmm.....now things are getting really interesting. Both the UC Davis team and a Roclkefeller team were working with the same receptor for 1-octen-3-ol(nananol), a molecule produced by the skin that mosquitos use to home in on humans. It is dependent on a co-receptor to function properly, and DEET blocks the co-receptor. The Davis team concluded that the mosquitos were repelled by DEET based on additional experiments using a sugar solution as an attractant and noting that they wouldn't approach it when DEET was added to the environment. The Rockefeller team concluded that because DEET was masking the nananol, that was sufficient to confuse the mosquitos. They also noted that the co-receptor is not involved in the detection of CO2 and thus mosquitos can still detect it. Apparently detection of one attractant is not enough to get the mosquito to home in? Nothing was mentioned about lactic acid. As I said, things are getting interesting. My source is from March, 2008: sciencedaily.com/releases/2008/03/080313143052.htm

Another very interesting link in the Science Daily article I am referencing was to some emerging research tentatively concluding that DEET is a central nervous system disruptor through a mechanism similar to that of nerve gases. For anyone concerned about possible side effects of using DEET, I would highly recommend reading this article. It is a legitimate scientific source. As always, verify this to your own satisfaction.

This probably more than OP intended, but what the heck, Ben, it's interesting stuff, huh?

Edited by ouzel on 08/11/2010 17:44:30 MDT.

Hi Sean, I had a very similar question a while back and got a lot of informative feedback. Maybe you'll find the thread helpful

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=29218

enjoy!