Spartan Mosquito Eradicators are selling like hotcakes around the country so I bought two and thought I’d share some thoughts. The devices are just black tubes filled with water, sucrose, salt, and yeast, and you hang them at different places in your yard according to instructions that are included. Per the company, mosquitoes are lured to the devices by the CO2 produced by a yeast, crawl inside (through holes in the cap), drink the liquid, crawl back out, then eventually die when their guts rupture. Here is one hanging in my yard:

The science behind the devices

There are several reasons why such a device might be expected to work.

First, it is well-established that mosquitoes obtain carbohydrates from decaying (fermenting) fruit, and several studies have shown that mosquitoes are attracted to solutions of sucrose and yeast (Oli et al. 2005, Smallegange et al. 2010, Sukumaran et al. 2015, Dhanique et al. 2017) .

Second, it is well established that mosquitoes can be effectively lured to and killed by sugar solutions that are laced with poisons (reviewed by Fiorenzano et al. 2017).

Did they work?

No. I didn’t notice a drop in the number of mosquitoes in my yard. My mosquitoes are largely Asian tiger mosquitoes (Aedes albopictus) and several Culex species. I spend a lot of time outside so I would be in a position to know whether there was a reduction in mosquitoes. The devices simply didn’t work.

That said, the Spartan Mosquito Eradicator is quite effective at killing small organisms other than mosquitoes. Below are photographs of the some of the insects I found trapped inside. One of the two traps is harboring living fly larvae (I don’t know the species yet). Photographs of all the victims are available on my iNaturalist account.

• 

• 

• 

• 

• 

• 

• 

• 

• 

Below are photographs of insects on or near my Spartan Mosquito Eradicators. I checked the devices probably 100s of times during the summer and I’ve never seen a mosquito on or near them. And I most definitely have mosquitoes in my yard — mosquitoes are just completely uninterested in the devices.

• 

• 

• 

Why didn’t they work?

In my opinion, there are three reasons why the Spartan Mosquito Eradicator is unlikely to kill a single mosquito unless it falls from the tree and lands on one.

First, the holes in the cap are too small (5/32″) to allow mosquitoes to enter. There’s not a huge literature on what size holes mosquitoes can crawl through, but Dickerson et al. (2018) found that only 1 out of 100 female Aedes aegypti mosquitoes went through an 8-mm hole after 1 hour. So a hole of 5/32″ (4 mm) is likely too small. Furthermore, although a truly desperate, hungry female mosquito might squeeze itself through a small hole in search of a warm mammal (Bidlingmayer 1959), I doubt that they would do the same merely for some rotting fruit, especially if a yard is full of easier sources of sugars (they like flower nectar, e.g.).

I understand that the small hole size is necessary to exclude larger insects like honey bees, but I’m perplexed why something a tad larger wasn’t used. I glanced at the company’s patent application and even there the hole sizes are too small (3/16″ maximum). It makes me think they didn’t have a good grasp of basic mosquito biology and morphology prior to submitting the patent application. That’s just a guess.

It’s extremely strange that the Spartan Mosquito Eradicator website doesn’t show a single image of a mosquito entering or exiting a device, something that would be easy to photograph and highly useful for convincing a skeptical customer. I suspect the company doesn’t have such a photograph. It’s also “interesting” that the only video of the device in action (inside an aquarium filled with hundreds of mosquitoes) doesn’t show the holes in the cap. Below is a screen grab of the video:

My guess is that not a single mosquito in the video entered the device — they just died over the course of several days from starvation and desiccation. It would be nice to know whether the company filmed it exactly as above (with holes hidden) or whether the company cropped out the holes after filming. Both of those scenarios would suggest deception was the goal of the video. Somebody knows the answer to that but I’ve been unable to get the company to give me details.

Second, sodium chloride (table salt) is extremely unlikely to be an effective poison. My pessimism is because adult mosquitoes have salt-sensitive taste receptors just like we do and thus are rather unlikely to drink a solution that has such a high concentration of salt. I was unable to find a single published article that suggests mosquitoes would drink salt/sugar solutions. Similarly, I couldn’t find any literature that said mosquito guts would explode when forced to imbibe sugar/salt/yeast solutions. Indeed, when females take a blood meal they are, in effect, ingesting a high-sodium solution. They simply excrete the excess sodium in their urine.

Why, then, does the company use sodium chloride as the active ingredient, when even a quick internet search would reveal it is poor choice? The answer is a little complicated, but (I think), revealing about company’s motivations.

It turns out that the company initially used boric acid as a poison. I’ve uncovered two types of evidence for this. One is that “orthoboric acid” (not sodium chloride) is listed in the patent application. Another is a a video of the inventor/co-owner (Jeremy Hirsch) describing the poison as “boron or borax” to the Hattiesburg (Mississippi) City Council in April 2017; he doesn’t mention a salt version. I think he first settled on borax (which is cheap and easy to find) because he likely read, sometime in 2015 or 2016, an article in the New York Times titled, “Brewing up double-edged delicacies for mosquitoes“. In one part of the article there’s a description of an experiment that used boric acid to control malaria-transmitting mosquitoes in Africa. I think this was the article because Mr Hirsch often mentions in interviews that he thought he could improve upon what the Gates Foundation was doing (described more fully in Müller et al. 2010).

My guess is that at some point Mr Hirsch realized he wouldn’t be able to get EPA approval for the borax version so he switched to sodium chloride because it’s completely exempted from FIFRA (Federal Insecticide, Fungicide, and Rodenticide Act). Using table salt allowed him to sell it in almost every state without going through any type of testing. I.e., the Spartan Mosquito Eradicator can be sold even if it doesn’t work. I think Mr Hirsch was again inspired by that that NYT article, which described boric acid as “about as harmless to humans as table salt is.” I’m guessing that Mr Hirsch (who used to own a restaurant) assumed that this phrase meant that table salt could be substituted for boric acid. Or, potentially, Mr Hirsch knew all along that the salt was not going to work but used it anyway. Given that Mr Hirsch use to work in a chemical factory and that his partner (Christopher Michael Bonner) is a chemist who owns an analytical testing company, I think the latter explanation is far more likely. They likely know that the solution isn’t going to kill mosquitoes. I bet everyone who works at the company knows.

One odd part of the sodium chloride usage is how to company describe the mechanism of action: the mosquito gut “ruptures” in response to sharp crystals of sodium chloride. Even if you could fool a mosquito into ingesting a saline solution, this mode of action is laughably improbably. I.e., the salt in the solution is not going to suddenly crystalize. Ever. Sodium chloride is ridiculously soluble in water so you’d need to have an extremely high concentration for salt to crystalize out of a solution. That’s simply grade-school chemistry. So I’m guessing the advertising was initially crafted to describe how boric acid kills insects and they decided to keep the wording (which sounds dramatic) after switching to (boring) salt. Boric acid acts in the gut, too, and some sites claim (without proof, I think) that it ruptures the gut.

Third, the yeast is going to run out of sucrose in less than ten days (probably just two). In fact, they might not be emitting CO2 at all — the yeast they used might be killed by the salt. There are special yeasts that can deal with high salt concentrations but my guess is that they would choose the cheapest version they could get. Regardless, the devices are probably emitting close to zero CO2 for most of their 90-day lifespans. I suspect CO2 is only produced by the decomposition of the insects that drown in the fluid. Mosquitoes are not attracted to rotting insects, of course.

Why do people buy them?

Some people LOVE the Spartan Mosquito Eradicator, and they are rather vocal about that love. For example, more than half of the reviews on Amazon award it 5 stars. This is fascinating because I think this is a product that simply cannot work as currently designed (mosquitoes can’t get inside, they won’t drink the fluid, carbon dioxide isn’t being produced past 10 days).

What might cause so many people to give 5 stars to something that doesn’t work? My hypothesis is that many of these happy reviewers live in an area that received aerial insecticide sprays soon after the devices were set up — many towns in the United States spray regularly in this way, and few people know that this happens. Other purchasers might just happen to have had low mosquito counts in their yards for some other reason (e.g., very little rain prior to setting the devices out in yard). Both of these scenarios can lead the average person to conclude (strongly believe) that the devices they purchased caused the low mosquito numbers. I.e., they succumb to illusions of causality, a common mechanism that explains why people believe strongly in all sorts of strange things (dowsing rods, e.g.). Then, when they rave about the (assumed) causality on Amazon or Facebook they publicly affirm their belief. I think this latter phase is called escalation of commitment. No amount of evidence to the contrary is likely to change their Belief.

An additional reason to be suspicious of all the 5-star reviews on Amazon is that the pool of people who order miracle gizmos in the first place is probably not a random sample of people. I.e., such buyers might be far more inclined to think such a thing could and will work.

Another category of true believers are the owners of stores that sell Spartan Mosquito Eradicators. These individuals get a percentage of sales so they are potentially biased, but in my experience speaking they are 100% convinced that the claims on the package must be true (why would the company have mislead them!?). The proof, to them, is that people keep buying the devices. Again, no amount of evidence is likely to convince them that the devices don’t actually work. Arguably, trying to reason with them simply strengthens their belief.

As a side note, I find it bizarre that the 5-star true believers keep buying replacement packs every 90 days. If these people are truly convinced that the devices work they could save a lot of money by just going to the pantry and refilling the tubes with fresh ingredients (I did the math: 2 1/2 tbsp sugar, 1 tsp salt, 1/8 tsp yeast, 1.7 cups warm water; you’re welcome). The company is clearly concerned about this scenario and has the following warning: “Spartan Mosquito Eradicators cannot be reused or refilled. Imagine a glass of orange juice sitting on your porch for 3 months. We don’t want people pouring tubes out on the ground and having a house pet consume the materials” (italics added). That’s seriously the stupidest thing I’ve heard in over a week.

Deceptive advertising

One reason so many people buy the devices is that they believe the marketing, probably because it shrouds its claim in sciency words and figures. Take, for example, the graph that it uses to claim mosquito populations are all but eliminated in 90 days:

A typical person is going to see this graph and assume that an actual experiment was done. It’s theoretically possible the graph is based on real data but I wonder whether the company just made it up. Data from real experiments just don’t look so perfect. I could make a graph like that in approximately 4 mins. The company seems prepared for such criticism, however: “Spartan Mosquito does not warrant that any of the materials on its web site are accurate, complete, or current.”

The company makes other bold claims, too. For example, it claims without evidence that the Spartan Mosquito Eradicator is better at controlling mosquitoes than pyrethroid spray services, automatic pyrethroid foggers, bug zappers, citronella candles/torches, and DEET repellents. There might be issues with some of these control methods but they are all better than the Spartan Mosquito Eradicator which is completely ineffective. The efficacy of a Spartan Mosquito Eradicator is probably exactly the same as ultrasonic mosquito repellers (which the FTC has tagged as frauds).

I am almost certain there are scientists out there who have tested these devices and found that they don’t work at all. E.g., it wouldn’t take long to see that mosquitoes can’t, or won’t, go through the holes in the cap. But anyone agreeing to test the devices for the company is prevented by a non-disclosure agreement (NDA) from publicizing that fact. Note to those scientists: you can break an NDA if you think the company is engaging in illegal activities (such as false advertising).

Unethical customer support

In the rather likely scenario that the device doesn’t work, customers should have the option of returning it for a full refund. However, the company has a carefully-crafted return policy: “Lights On Distributors [the distributor] does not honor returns due to improper use” (italics mine), and you have to return the product within 30 days (too soon to confirm it doesn’t work). The company always blames the user if mosquito populations are unchanged. Specifically, Mr Hirsch et al. will insist that the user failed to (1) “deploy” the devices early enough, (2) buy enough units for the size of the property, (3) place them in right spots, (4) place them at the right height in trees, or (5) wait long enough for devices to start working their magic. In some cases, all of the above. I fully understand that some devices don’t work if instructions are not followed, but I’d argue that this is not really one of them. The insistence that directions weren’t followed is just a scheme to prevent people from returning the product and to immunize the company against scam complaints.

If a buyer persists in claiming the devices simply don’t work, the company will ask the customer to call a “Deployment Specialist”, somebody who will call up your street address on a Google satellite map and tell you where you should put the devices (after you buy more). Sometimes the representative (Mr Hirsch himself, perhaps) will even inform the customers that it is really hard to educate the common person on the complex task of deploying the devices, all while referring to the customer as, “Sir” and “Ma’am” (which conveys politeness and annoyance at the same time). These tactics are not just patronizing, they are dishonest. Also, having a stranger examine your property on Google maps is creepy, especially if the interaction is done under duress. Given the name, “Deployment Specialist,” I’m assuming Mr Hirsch used to be in the Army.

What should be done?

Please consider sharing this post on Facebook and Nextdoor to help get the word out. If you feel this post is too wordy (sorry), here’s a PSA image to download (right-click) and share:

If you work for a vector control district or state health department, please alert the residents in your area. It’s not just to save them money: a growing number of people are relying on Spartan Mosquito Eradicators to protect their families from West Nile virus, Zika virus, and other diseases. Given the severity of those and other diseases, that trend is alarming.

If you have a few minutes, please log a complaint with the BBB, Consumer Affairs, Truth in Advertising, or the FTC . The FTC, in particular, has the power to slam a company with legal action. And the FTC has a history of slamming companies that hawk snake-oil mosquito devices. If you are leaving a review on Amazon, please post photographs of the liquid inside the container to show people that no mosquitoes are present. Photographs are extremely persuasive.

As far as I know, nobody has taken the company to court (except for a trademark issue). For most people, being swindled out of $19.95 isn’t going to elicit a lawsuit. But some have spent tens of thousands of dollars on these devices. For example, Blue River, Wisconsin, bought 10,000. That’s enough money to warrant a suit, I think. I’ve also heard that Lamar County, Mississippi is considering using taxpayer dollars to buy Mosquito Eradicators (the company, in related news, has donated $16,000 to fund the local SWAT team). If you live in a town that has purchased them, let me know.

By the way, here are photographs of the owners, Jeremy Hirsch and Chris Bonner. Spartan Mosquito Eradicator is the fictitious name for the actual company, AC2T. The word on the street is that it’s raking in about $15,000,000 per year.

• 

• 

More information

If you have details that I might have missed, please email me. I’m also happy to field questions. For the record I have nothing to gain if Spartan Mosquito Eradicator fails. Also, I hate mosquitoes.