Category Archives: Education

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 or patches

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

These devices are really good at attracting and killing fruit flies, ants, and wasps. They don’t attract or kill mosquitoes, unfortunately. 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.

Templates for better posters

There’s been a frenzy of discussion on Twitter this summer about conference poster design (see #betterposter, #betterposters, #butterposter) so perhaps it’s a good time to re-share my Powerpoint templates. If you’re new to posters please see my page, “Designing conference posters” for details.

Below is a standard horizontal template. I recommend 500-800 words and 1 or 2 graphics that are understandable without you needing to explain them.


Note that there is no requirement for the text boxes to have a line around them — it’s easy to set line width to zero. And if you want to delete the background color (gray, here), you can eliminate the “rectangles within rectangles” look. Totally up to you.

If you want to include a QR code, put it at the bottom so that it doesn’t distract from your interesting graphs and illustrations. Like this:

But be cautious about including a QR code. By design it invites a viewer to fire up their camera phone, and I’d wager that most will also take a pic of your entire poster. So skip the QR code if you don’t want people to take pics of your poster. A compromise is to print business cards that have the QR code (as well as poster title, your name, your email address) and then leave them in an envelope pinned next to your poster (“please take one!”).

Here’s a template that moves the Literature cited, Acknowledgements, and Further information to the far right column … which causes the Materials & methods and Results areas to have more room. But the Conclusions box gets squished (such is geometry).


Here’s a template that might work for a humanities topic. I’ve chosen to have a question/result/conclusion flow (from left to right) inside the main arena, but you can always rearrange. There are also no rules about section names — just redo those, too.


The final template is a portrait-style one. For this orientation I think it’s critical to put the least important sections on the very bottom (that position is really hard to read without stooping).


If you’d like to read an article about the better posters frenzy, here’s one from Inside Higher Education in which I’m quoted a few times.

Alternative lawn signs for Mosquito Shield

Mosquito Shield is just one of dozens of companies that spray pyrethroids to kill mosquitoes. Homeowners typically pay $800 per summer for treatments spaced every 21 days and, as part of the deal, agree to feature a sign in their yard for the season.

Two types of people have these yard signs. The main category is homeowners who fully understand that pesticides have bad environmental effects but who simply don’t care. These are likely the same people who knowingly drive with their high beams on at night (“It’s safer for ME!”). And then there are people who were duped by the pesticide companies into believing pyrethroids kill only mosquitoes.

To better reach this second type of person as well as those who are interested in mosquito sprays but are still on the fence, I’ve fabricated six signs that highlight the fact that pyrethroids kill other animals:

All the signs are fairly self-explanatory except for perhaps the Bird Shield one. Pyrethroids don’t kill birds directly but many species depend on insects and spiders to feed themselves and their young. So when you hire Mosquito Shield to nuke your yard every three weeks you are reducing the numbers of birds that can survive in an area.

I realize that none of the above signs is going to be used by an actual pesticide company. Their business model is to obfuscate about the effects of pyrethroids. Indeed, most companies try to hide the fact that their mosquito sprays even contain pesticides. That’s why the government (federal and/or state) should require companies to clearly indicate the active ingredient of the spray. Here’s how it could (should) look, thus allowing curious neighbors to Google the chemical and be horrified.

Pyrethroid sign for Mosquito Shield

If you are an influential part of a local government, please consider enacting an ordinance that requires disclosure of the pesticide name on signs.

If you need an individual sign for your a presentation, here are some image files: fireflies, butterflies, bees, spiders, fish, birds.

Please share this page on your neighborhood social media to get the word out. These companies are spreading in popularity and it’s horrifying.

More details here.