Tag Archives: repellent

Bag of water hanging from ceiling

15 mosquito-control strategies and devices that don’t work

Health officials love to remind people to use DEET and other CDC-approved repellents, but they tend to shy away from telling the public what doesn’t work. As a result, millions of people adopt ineffective techniques and gimmicky devices. These people are not only subjecting themselves to annoying mosquito bites, they are increasing the likelihood that family members will contract West Nile virus disease, Zika virus disease, eastern equine encephalitis, and other mosquito-borne diseases. So I thought I’d make a list of the top myths and scams just in case skeptical people are Googling.

1. Mosquito-repelling plants

Despite the claims of thousands of posts on Facebook and Pinterest, there are no plants that, when planted around your yard, repel mosquitoes. And, just to be clear, the plant marketed as “mosquito plant” does not repel mosquitoes. I know this is deeply upsetting news to many plant fans. I’m just the messenger.

2. Ultrasonic devices and apps

None of these have been found to work (details). It’s too bad. It would be really cool if they did. The FTC has taken some companies to court. There is, however, a device called The Mosquito that is effective at repelling teenagers.

3. Bags of water suspended from ceiling

This belief is common in Mexico, Central America, Spain, and certain pockets in the U.S. south. It’s a variation of the equally-ineffective tradition of hanging bags of water to repel house flies. Some people insist that you have to add coins (and just the right number).

4. Listerine

Nope — even when mixed with other ingredients like beer and epsom salts, spraying Listerine around your yard won’t repel mosquitoes. Just another internet rumor started by somebody with too much free time.

5. Citronella candles

Citronella candles only seem to work if you surround yourself with a lot of them, ideally in a protected area so that wind doesn’t dissipate the smoke. Similarly, Tiki torches that burn citronella-laced oil are ineffective. They smell great, though. The pleasant smell most likely contributes to the strong placebo effect. People absolutely believe they work even though they do not.

6. Bounce dryer sheets

Per one study fungus gnats (which don’t bite) were mildly repelled by dryer sheets. I’d wager these sheets might actually be attractive to mosquitoes (some species home in on perfumes).

7. Wrist bands with natural oils

At best, wrist bands will reduce the number of mosquito bites on your wrist. But they will not emit enough volatile compounds to shield the rest of you. NB: currently there are no wristbands that contain DEET or other CDC-approved repellent. Details.

8. Stickers laced with natural oils

Stickers only prevent mosquitoes from biting the flesh directly underneath the sticker. You’d need an awful lot of stickers for full protection. If you can rock that look, I say go for it. Note, same conclusion for the stickers that claim to infuse your bloodstream with B1.

9. Garlic

Eating garlic does not deter mosquitoes. Just other people.

10. Vitamin B1, B6, or B12 pills

Nope, nope, and nope. Details. More details.

11. Mozi-Q pills

Just another scam. Details.

12. Bug Zappers

These devices are adored by people because they make a satisfying crackle when an insect meets its end. Indeed, people who own these seem to delight in the attention these things get when friends come over in the evening. But if you dump all the carcasses on a table and sort them (good family fun), you’ll find that only a small fraction of the victims will be mosquitoes. In one study, 0.22% were mosquitoes. Mostly you’ve just electrocuted thousands of small, defenseless moths and night-active beetles. That’s a lot of bad karma. More details.

13. Dynatraps

These don’t appear to work. If you’re still on the fence read some of the many 1-star reviews on Amazon.

14. Spartan Mosquito Eradicators and Sock-It Skeeters

These are a commercial manifestations of the “DIY mosquito killer using soda bottle, yeast, and sugar” that has gone viral on Facebook and YouTube. Like the homemade version, these devices are really good at attracting and breeding fruit flies ( (they lay eggs!), but nothing else. They do not kill mosquitoes. Both devices are made by AC2T, Inc., a Mississippi company. More details.

15. Bats and birds

Sadly, it’s a myth that constructing a bat or bird hotel in your backyard will eliminate your mosquito problem. Bats and birds will certainly eat mosquitoes under some circumstances (e.g., when they are caged with nothing else) but under natural conditions they prefer to eat larger insects. You should still construct bird and bat houses, though. Details.

More information

If you have questions, email me.

How to protect yourself from ticks

I spend a lot of time outside, sometimes face-down in the weeds trying to get a photograph of something small. So I have some opinions about tick prevention and thought I’d share.

blacklegged (deer) tick on sock
Ixodes scapularis
  1. Spray or soak shoes, socks, pants, shirts, hairband, hat, etc., with permethrin (buy online or at outdoor stores), then let dry before you using. Chemical only slowly washes out so you only need to reapply every 5th laundering or so (or after 5 months if you don’t wash your clothes). Spray your backpack with permethrin, too, because you likely set that on the ground during breaks. Do not spray permethrin on your skin. You can also buy clothing that comes pretreated with permethrin.
  2. Spray your clothes and skin with DEET, picaridin, para-menthane-3,8-diol, IR3535, or 2-undecanone. DEET really is the best. Note that “pure” oil of lemon eucalyptus (extracted from Corymbia citriodora) is not currently recommended by the CDC; the oil has small, variable levels of para-menthane-3,8-diol but apparently not enough. All of these repellents do not last like permethrin so reapply every few hours. Do not spray DEET on anything plastic (it will melt).
  3. Be suspicious of “natural” or “organic” concoctions that claim to effectively deter ticks. If one of these recipes actually works the CDC would recommend it. I’ll update this page when that happens. Similarly, avoid apps, crystals, and dietary supplements. If you need help convincing a friend to just use DEET (it’s super safe), mention that DDT is a different chemical that just happens to start with the same letter. DEET is also gluten and GMO free.
  4. Wear light-colored clothing so you can better see ticks. Like this person. Note that this strategy fails with tick larvae because they just too small to see unless you are wearing something pure white and have really good vision.
  5. Tuck your pants into your socks. Like Kanye West. You can even buy tick socks that are treated with permethrin and have a tight weave that prevents larvae from burrowing through the fabric.
  6. Wear tall, light-colored, glossy boots that ticks can’t easily climb. I suspect that larvae and nymphs can still climb glossy surfaces, though. I own a pair of Muck Boots and they have a neoprene surface that I suspect ticks can easily scale. I’m considering switching to something like a Gumleaf boot.
  7. Buy some gaiters and treat them with permethrin. Some gaiters are even designed to keep out ticks. Some even come in lime green. (NB: Lyme disease is named after Lyme, CT.)
  8. Buy some arm sleeves. Like gaiters, you can even buy ones that are already infused with permethrin.
  9. Shave your legs.
  10. Keep checking for ticks as you hike. If you are hiking with others, scan them for ticks, too.
  11. Keep a roll of duct tape handy so that you can easily remove ticks. Travel-sized lint rollers are good, too, and easily attach with a carabiner to a backpack.
  12. Put your field clothes into quarantine when you come home. Ideally, launder them immediately. Ticks can wander off of clothing and backpacks and show up later.
  13. Get naked and check for ticks. Everywhere. This is a really good reason to get a girlfriend or boyfriend even if you’re not really into them. Don’t tell them that.
  14. If you have limited neck mobility, invest in a nice automotive inspection mirror so you can see all the various parts of your body you never look at. You can even buy lighted ones. You can also use a selfie stick and a smart phone, but that’s risky if you accidentally forget to delete the photographs and video.
  15. You probably don’t want to know this but ticks are fond of lodging in ears. Get yourself an otoscope if you feel something in there. You can even buy phone attachments to get pics.
  16. If you find a tick that is attached, take a photograph (like this) then remove the tick. Carefully. I have a Tick Key (see one in action) but there are lots of types. Then take photographs of the bite location and of the tick. If you live in Pennsylvania, send the tick out for free testing. If you live elsewhere, put the tick in vodka or in the freezer in case you need to get it tested later.
  17. Take a long hot bath with a lot of soap. Ticks are hardy but you might dislodge an unattached nymph that somehow got past your first-line defenses.
  18. Once you are de-ticked and clean and have the laundry running, post photograph of tick on iNaturalist so you can get an identification. Here are the ticks of North America on iNaturalist. You can also send pics of ticks to TickEncounter for ID.
  19. Monitor the attachment spot closely. If a red spot appears, take daily photographs with ruler in frame so that doctor can assess progress of redness. Here are pics of Lyme rashes. You can even mark the progress with a Sharpie. There are plenty of other diseases transmitted by ticks, though, so don’t rely on rashes.