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 device

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).

Third, I’ve heard from mosquito researchers that mosquitoes can crawl through very small holes (e.g., when looking for an oviposition site).

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. Within a few weeks the surface because a bubbling, charnel pit. Some of the visitors clearly lay eggs before they die because you can find larvae writhing around:

Below are photographs and IDs of the some of the insects I’ve found trapped inside. Notable is the presence of spotted-wing Drosophila (Drosophila suzukii), a serious pest of orchards and berry fields. The adults found inside the trap were all dead but of concern is that the females oviposited into the liquid, and one of the traps had living fly larvae. Photographs of all the victims are available on my iNaturalist account.

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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.

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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, at least with regard to mosquitoes in search of rotting fruit. 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 when presented with a host. So a hole of 5/32″ (4 mm) is likely just 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 seem too small (3/16″ maximum).

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. I’d love to be wrong about that. 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 even 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. 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 salty sugar solutions. Similarly, I couldn’t find any literature that said mosquito guts would rupture 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.

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.”

One odd part of the sodium chloride usage is how to company describes 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 improbable. 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. A 1% solution isn’t going to crystalize. I’m guessing the advertising was initially crafted to describe how boric acid kills insects and they decided to keep the wording. Boric acid acts in the gut, too, and some sites claim (without proof, I think) that it ruptures the gut.

As an aside, just in case an EPA regulator chances upon this post, listing sodium chloride as the active ingredient seems like a violation of the 25(b) exemption granted to this device. I.e., the sodium chloride is not actually killing any mosquitoes (because they don’t seem to even go inside) so it cannot be listed as an active ingredient. Similarly, Spartan Mosquito often suggests in marketing materials that the mosquitoes are killed, in part, because their guts are ruptured by the yeast’s CO2 emissions. Therefore, failure to list yeast as an active ingredient might be a violation.

Third, I don’t think the concoction is attracting mosquitoes. If it were, I would expect to see mosquitoes congregating around the device. I didn’t see a single mosquito, ever. As for reasons why the fermenting liquid isn’t attractive, it might be because the yeast runs out of sucrose in less than ten days (probably just two). Or, perhaps, the lack of attractiveness is because the odor profile is changed by rotting carcasses.

Why do people buy them?

Some people LOVE the Spartan Mosquito Eradicator. For example, more than half of the reviews on Amazon award it 5 stars.

What might cause so many people to give 5 stars? 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 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.). Once a person decide the devices work the power of confirmation bias will continue to reinforce their conclusion. 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. That’s also true of people who see the devices in stores; skeptical folks might pass by the display and laugh but others will see the package and assume it works.

Another category of fan is 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 with them they seem 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 (thousands, in some stores). My guess is that people who figure out that the devices are ineffective will just say to themselves, “Well, dang, I just wasted $19.95 but I’m not going to waste any time trying to return the darn thing. And I’m not going to bother the nice folks at the store that sold it to me. They’ll just trying sell me a fresh box.”

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, 1/18 tsp yeast, 1.7 cups warm water). The company is 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).

Some 1-star reviews from Amazon

Some reading this review might think I’m biased in some way, so I thought I’d give you some snippets from several of the many negative reviews on Amazon.

“The container is a long skinny smooth tube. It has six tiny holes up on top. Supposedly, the mosquito will, somehow, detect the C02, fly up to the tip of the smooth plastic tube and squeeze itself in this 4mm hole, tucking its legs and body in as it slides itself in this pin hole. Then once inside, fly down the narrow shaft take a drink of water, fly up the thin shaft, and once again tuck its legs in and squeeze itself through to fly away. This concept is so far fetched. I would like to see real proof than unproven customer reviews. It would be great that the manufacture would show real data and show mosquito accessing these tubes as they say. I opened one up and poured the contents out. Only bugs I see are fruit flies and a few house flies, but not mosquito’s. I will take pictures next time. I find it interesting that the manufacturer mentions that the mosquitoes fly out, thus you will not see any mosquitoes trapped in the tube. Yet, fruit flies, and house flies, which are notoriously way better flyers and can crawl, can not find their wait out of the trap.” — bahhhoo (full review)

“This product is a scam. The “active” ingredients are salt and sugar. You know, Malaria is a global problem. Don’t you think that if salt (aka sodium chloride) and sugar (aka sucrose) could actually reduce or eradicate mosquitoes, this product would win the inventor the Nobel Prize? The trap will collect some flies and bugs attracted to the sugar, but no mosquitoes. Also, if you write a “bad” review, the sellers contact you and tell you that you aren’t “installing” it correctly. You see, you have to put just the right number of traps in just the right locations in your yard. Yeah, right.” — Caveat Emptor (full review)

“I checked the traps several times over the course of the following months. Not only were the mosquitoes as bad as ever, the traps seemed EXCELLENT at trapping ants and gnats, but not a single mosquito that I could tell. I’d say don’t waste your money.” — Customer (full review)

“These are useless. As another reviewer wrote, just look at the ingredients. I’ve noticed no change at all over the last few weeks these have been out. There are very few products that fit into the category of feeling like I was suckered for buying them and this is definitely one of those purchases.” — Tecsun (review)

A 5-star review on Amazon

This 5-star review is the most popular 5-star review for the product. The reviewer concluded that Spartan Mosquito Eradicators don’t work but gave them 5 stars because the company sent her some more. You really can’t make this stuff up.

“My first review I gave one star because they did not work for me. I am now giving 5 stars for customer service. … I am going to hang as instructed and really hope they work. If they do I’m going to always have working sets hanging and encourage all my neighbors to do the same. I will update in a month with results. Very hopeful. Worth every penny if it will work.” — Tammy (full review)

Deceptive advertising

One reason so many people buy the devices is that they believe the marketing claims, probably because it seems sciency. Take, for example, the impressive 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. Oddly, no details about this graph are ever given on the website or elsewhere (who collected the data?, where was it done?, when was it done?, how was it done?). I’ve talked to a lot of people about this graph and I think it shows the number of mosquitoes landing on Mr Hirsch’s arm on two different days during an event the company calls, “Case Study CSL4GOV-ZIKA”. Here’s a handout the company distributed (details below):

The document says that a Lamar County official (Joseph Waits) and an etymologist [sic] from the Mississippi Department of Health conducted a study in late 2016. It is worded to imply that the Spartan Mosquito Eradicators deployed in the area eliminated 100% of mosquitoes and that the Mississippi State Department of Health participated and approved of the data. It turns out the reason the final mosquito count was zero was because the State of Mississippi completely nuked the neighborhood with insecticides (on multiple days). The State of Mississippi was focused on preventing the spread of Zika (from a single patient in the neighborhood) and had zero interest and involvement with the devices. The word on the street is that MS Department of Health is not pleased about how the document above was worded.

I’d also like to point out how the company ended the document: “To date, this is the most effective, longest-lasting Zika control response on record anywhere.” That’s a very bold claim. And appears to be a violation of the 25(b) exemption granted to the device. I.e., Spartan Mosquito implies the product can protect against a human disease. The claim is also made online: “Purchase the Spartan Mosquito Bomb and fight the Zika virus!”

The company makes other bold claims, too. For example, it claims 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.

Finally, the company claims its devices are chemical-free. That’s not true (because NaCl, H₂O, C₁₂H₂₂O₁₁). Claiming a product is chemical free is also illegal.

It’s not just the company that spreads false, unsubstantiated health claims. Its affiliates and distributors do, too.

Here’s a typical post from the primary distributor, WDG Holdings, LLC. The implication is that you should buy a Spartan Mosquito Eradicator to protect yourself and family from eastern equine encephalitis. It is illegal to claim such protection when there is no credible scientific backing. Yet this distributor’s Facebook posts are almost exclusively claims such as this. These posts help explain why so many customers (feed stores, hardware stores) of the distributor make identical claims.

For example, here’s a commercial by Hub City West Farm and Garden that was broadcast on Mississippi television in early 2019. It claims Spartan Mosquito Eradicators can protect your family and pets from mosquito-borne diseases. Totally illegal. And because the claim could result in people not protecting themselves with DEET, also morally wrong.

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 aren’t particularly interested in going 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 discussing the results. Note to those scientists: you can break an NDA if you think the company is engaging in illegal activities (such as false advertising).

Terrible customer support

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. Per hundreds of interactions with 1-star reviewers on Amazon, the company always blames the user. 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 seems like a scheme to prevent people from returning the product and to immunize the company against scam complaints. Here’s a typical response (from Spartan Mosquito’s Facebook page):

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.

By the way, if you do end up speaking with a deployment specialist and want a visual, here are photographs of the owners, Jeremy Hirsch and Chris Bonner.

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What can be done?

Please consider sharing this post on Facebook and Nextdoor to help get the word out.

If you have clout in Mississippi, email Michael Ledlow (michaell1@mdac.ms.gov), the director of the Mississippi Bureau of Plant Industry. This is the office that granted Spartan Mosquito Eradicator a 25(b) FIFRA exemption in 2016 and in so doing opened the door for other states to grant exemptions. The MS BPI can take that permit away at any time if Spartan violates 25(b) rules. Even a single violation results in loss of the exemption (presumably). The office can also request that Spartan Mosquito provide valid efficacy data. To date, Spartan Mosquito has not provided efficacy data.

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 local governments have spent tens of thousands of dollars on these devices. For example, Blue River, Wisconsin, bought 10,000 Spartan Mosquito Eradicators. 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 Lamar County SWAT team). If you live in a town that has purchased them, let me know. Or if you contracted West Nile or easten equine encephalitis while expecting to be protected by a Spartan Mosquito Eradicator, please let me know (in addition to alerting your state health authorities). This is ripe for a class-action lawsuit, I’d wager (it raked in $15,000,000 in 2018).

But, sadly, it might be hard to sue the company for information on its website. Because this: “Spartan Mosquito does not warrant that any of the materials on its web site are accurate, complete, or current.”

Questions/comments

Please email me if you have any information that might be useful.