Tag Archives: sugar

DIY mosquito trap using a plastic soda bottle

Here are instructions for building an indoor mosquito trap using a 2-liter plastic soda bottle. All you do is add some bait (honey, fruit, juice, sugar water, or some nectar-containing flowers) and place in a dark corner of the room. It works because mosquitoes seek out sugar, which they require to fuel themselves. Once inside the bottle they can’t get out.

The above instructions are a modification of a Taiwanese science-fair project that eventually went viral. The differences between the original instructions and mine are that (1) I don’t recommend adding dry active yeast, (2) I suggest sugar sources other than granulated sugar, and (3) I don’t wrap trap in black paper. The omission of yeast is because I don’t think the generation of carbon dioxide is necessary to attract mosquitoes to sugar. In fact, adding yeast likely reduces the attractiveness and causes the trap to fail faster.

The critical part of the original instructions is to deploy the device on the floor in a corner of a room. This is because mosquitoes love to hang out in corners — they are dark and relatively free of desiccating drafts.


  1. The original instructions suggest 50 g (~1/2 cup) sugar and 200 mL (~1 cup) water but the ratio probably doesn’t matter at all. Brown sugar is likely better than granulated (white) sugar because it has more impurities (some of which are volatile). A drop of rose water might make the sugar mixture more attractive.
  2. Make traps with different types of bait to see which ones are most attractive to the species that are local. Anopheles coluzzii, for example, seems to prefer papaya and banana juice over mango juice (Nignan et al. 2020). Other species might prefer oranges. Or, perhaps, durian.
  3. Replace your bait when it stops attracting mosquitoes. Perhaps every four days if you use fruit (Meza et al. 2020).
  4. If you use flowers, opt for ones that have nectar (if you know) and are light-colored. Or stick a small potted orchid inside the bottle — their blooms last for weeks.
  5. If you happen to have a plant with extrafloral nectaries, that’s a great bait that will likely last for a long time (when you’re on vacation, for example). Try a bunch of wild cherry leaves, for example.

Why it works

Mosquitoes are famous for sucking blood, but like many insects they spend most of their lives quietly ingesting sugar from flowers and rotting fruit. For example, here are some mosquitoes nectaring in the middle of the day:

So when mosquitoes find themselves trapped inside, they will zero in on whatever you have on the countertops — fruit, puddles of syrup, cut flowers, or even a dirty sponge. I don’t have photographs of mosquitoes eating fruit inside but Justin Yoshida (Thailand) does: on jackfruit, on apple slices, and on eggplant. Mosquitoes indoors are likely not especially picky about fruit type because the option is starving to death. Mosquitoes even fall into juice containers and die, apparently, as one restaurant discovered.

In case you’re skeptical that these traps can actually work, here’s a video by somebody who followed the original (science fair) directions and killed 9-10 mosquitoes in 24 hours:

Why it won’t work outside

Don’t bother using these traps outside (the recommendation of the viral versions). Mosquitoes prefer natural sources of sugar so they will likely ignore anything inside a bottle, regardless of how delectable you think the concoction is. The exception would be if you live in a desert and there are no plants near your house.

The traps will also not work in rooms full of flowering plants or decomposing fruit. Similarly, if your kids spill juice and soda everywhere, the traps won’t work.

Adding toxins to the mix

If you have a house free of small kids and meddlesome pets, you can add bit of boric acid to the solution to create an attractive toxic sugar bait (ATSB) station. Then, when mosquitoes ingest the fluid they will die even if they manage to escape the trap (it can happen). In fact, once you have a toxin in the fluid you can and should just get rid of the funnel part of the trap — its presence is likely a barrier to some mosquitoes even though it’s relatively wide (~2 cm). Instead, cut a 3 cm hole in the side and keep the cap on the bottle. Note that because these devices are indoors you don’t need to worry about the boric acid (or whatever) poisoning the pollinators in your yard.

The above is nicely explained by Andy Lee Graham:

One perk of adding boric acid is that fermentation will likely be slowed down, extending the life of your fruit juice. Note that fermentation will occur even though you haven’t added any yeast. Fungal spores are present everywhere.


Spartan Mosquito Pro Tech

Here’s an early look at the Spartan Mosquito Pro Tech, the newest device made by the makers of the wildly popular Spartan Mosquito Eradicator, which I reviewed in 2019.

What is the Spartan Mosquito Pro Tech?

Aside from differences in label design, the Pro Tech looks just like the Eradicator — a plastic tube fitted with a cap that has several ~11/64″ holes and a hook for hanging. And it’s filled with essentially the same ingredients (water, sugar, yeast). The big difference appears to be that the active ingredient is now boric acid instead of sodium chloride.

Per the labelling, the major differences are that the Pro Tech (1) works for 30 days instead of 90 and (2) “kills mosquitoes” instead of killing 95% of them.

The name, “Pro Tech”, is presumably to signify to consumers that the device is “professional technology”. This name is line with company’s description of the Pro Tech as “next-generation” and “most advanced“.

How does the Pro Tech kill mosquitoes?

The company asserts the following occur:

  1. mosquitoes are attracted to the tubes
  2. mosquitoes land on the tubes
  3. mosquitoes crawl around until they find the 11/64″ holes in the cap
  4. mosquitoes squeeze though the holes
  5. mosquitoes walk down sides of tube toward liquid
  6. mosquitoes ingest some of the liquid
  7. mosquitoes walk back up sides of tube
  8. mosquitoes find holes
  9. mosquitoes squeeze through holes
  10. mosquitoes fly away
  11. mosquitoes die from boric acid poisoning

A typical yard might have thousands of mosquitoes, so at any one time there might be a cloud of mosquitoes gathered around the devices, at least according to the company’s advertising. I have not been able to find a photograph that shows a cloud of mosquitoes around a Pro Tech.

Do Pro Techs kill mosquitoes?

The more important question is, “Does the Pro Tech kill mosquitoes in a yard?” The rephrasing of the question is important because a loophole in the EPA guidelines allows a company to claim a device kills an outdoor pest even if the efficacy experiment was done indoors. I’m not sure whether this is the case with the Spartan Mosquito Pro Tech, but it’s a concern. Laboratory experiments of attractive toxic sugar bait (ATSB) devices could easily overestimate actual efficacy for several reasons.

One worry is that boric acid can enter the vapor state. This means that mosquitoes trapped inside net cages with Pro Techs would be expected to die at a faster rate simply because boric acid is present in the air inside the cage, not because any of the mosquitoes actually squeezed through holes in the caps and ingested the liquid. Another huge problem is that when ATSB devices are tested inside cages, mosquitoes have no choice but to seek out the sugar inside the devices. So one might see mosquitoes entering the small holes of a Pro Tech inside cages even though mosquitoes in the real world would rarely do so. Under no circumstances would I recommend the EPA accept data from laboratory tests of ATSBs.

I’m not aware of any third-party evaluations of the Spartan Mosquito Pro Tech, but given that the Spartan Mosquito Eradicator does not work, it seems unlikely that the Pro Tech would work. I’ll update this page when peer-reviewed data are published.


Spartan Mosquito is suing me.

Jeremy Hirsch, inventor of the Spartan Mosquito Eradicator

Spartan Mosquito v. Colin Purrington

AC2T, Inc, a Mississippi company valued at over $100 million, is suing me in Federal court over my review of the Spartan Mosquito Eradicator. The device is a plastic tube filled with sugar, salt, yeast, and water and is purported to act as an attractive toxic sugar bait. Box claims that device will eradicate (kill) approximately 95% of mosquitoes in a yard for 90 days — the company does not release efficacy data, but claims it possesses them. My opinion is that the devices don’t kill mosquitoes, and the above review explains my reasoning. The owners, Jeremy Hirsch and Chris Bonner of Hattiesburg, Mississippi, seem particularly upset that I shared my review with state pesticide officials as well as federal regulatory agencies (EPA, FTC). The suit was brought to bankrupt and silence me, so it’s a SLAPP (Strategic Lawsuit Against Public Participation).

Here’s the first part of my motion to dismiss the lawsuit:

“In this lawsuit, Spartan seeks to use its superior financial resources to silence a former college professor who has been exercising his constitutional rights to petition his government and advocate on an important environmental and public health issue: the effectiveness of commercially available mosquito control devices. In Mr. Purrington’s opinion, based upon his personal evaluation of Spartan’s product and his scientific knowledge, Spartan has made false and misleading claims about the efficacy of its product, thereby violating federal environmental regulations and potentially endangering public health. Most of the statements that Spartan cites in the Complaint reflect Mr. Purrington’s efforts to reach federal and state officials with information about Spartan’s misleading and false claims concerning the efficacy of its product. The remaining statements reflect Mr. Purrington’s efforts to raise public awareness of the matters about which he is petitioning, describe his own opinions, or contain facts that Spartan does not, and cannot, deny are true. Applicable law does not provide Spartan with a valid claim against Mr. Purrington under those circumstances. Notably, even if Spartan could show that Mr. Purrington should be liable for his statements, Spartan fails to plead facts that would suggest it has incurred even a cent of damage to its business to justify its claims. That omission suggests that Spartan has sued merely to intimidate Mr. Purrington rather than to recover any demonstrable damage to its business. For those reasons, Mr. Purrington respectfully requests that the Court dismiss the Complaint in its entirety, with prejudice.”

The full brief is here (PDF).


Spartan Mosquito, Jeremy Hirsch, and Bonner Analytical Testing Company are being sued in New York District Court for fraud. Here is the 16-page complaint.

Scientists in Florida concluded the Spartan Mosquito Eradicators do not work.