Tag Archives: mosquitoes

Experiment shows Spartan Mosquito Eradicator do not work

Experiments on Spartan Mosquito Eradicators fail to detect efficacy

According to research conducted in Florida, there’s no evidence that Spartan Mosquito Eradicators kill mosquitoes. Here’s the citation:

Aryaprema, V.S., E. Zeszutko, C. Cunningham, E.I.M. Khater, and R.-D. Xue. 2020. Efficacy of commercial toxic sugar bait station (ATSB) against Aedes albopictus. J. Florida Mosquito Control Association 67: 80-83. PDF

I summarize the two experiments and explore some of the implications, below.

Laboratory experiment

Below is a rough reconstruction of the laboratory experiment they conducted. In each of the cages (BugDorm-2120), 100 male and 100 female tiger mosquitoes (Aedes albopictus) were released, then monitored for mortality at 24, 48, and 72 hours.

Schematic of laboratory experiment based on description in Aryaprema et al. 2020.

Below are the cumulative mortality data for the three cages. Result: the Spartan Mosquito Eradicator filled with the provided packet ingredients (treatment) did not result in higher mortality. I.e., there was no evidence the device killed mosquitoes under laboratory conditions.

Field experiment

The researchers also conducted a field experiment using two sites that had large populations of tiger mosquitoes (because of the presence of tires). At each site they deployed five tubes (separated by 4 m), switching whether the tubes were “treatment” or “control” tubes every 2 weeks. A BG-Sentinel trap (without carbon dioxide) was used to quantify mosquito numbers every week.

Schematic of field experiment based on description in Aryaprema et al. 2020.

Below are the weekly numbers of mosquitoes caught in the BG Sentinel traps. Results: there was no evidence that presence of treatment tubes (filled as per company guidelines) reduced the numbers of mosquitoes at the sites.

Conclusions

Their overall conclusion: “Both laboratory and field components of our study show that the Spartan Mosquito Eradicator is not effective in reducing abundance of Ae. albopictus.” They speculate that the contents do not attract mosquitoes and that the holes on the device (~3 mm) are too small for mosquitoes to easily reach the fluid inside. They also highlight the need for an experiment to evaluate whether the active ingredient (1% sodium chloride) kills adult mosquitoes. I.e., even if mosquitoes were attracted to Spartan Mosquito Eradicators and could easily get inside, the salt might not be lethal. Per unpublished research, a 1% salt solution is, in fact, not lethal to adult mosquitoes.

Implications

The results of the experiments call into question the efficacy claims made by the owners of Spartan Mosquito. For example, the company says on the box that a 95% reduction in mosquitoes will occur within 15 days and will last for three months. The company also prints a graph on the label that indicates almost 99% of mosquitoes are killed by the end of this period.

Spartan Mosquito Eradicator efficacy graph

If the claims are false or misleading, which seems to be the case, states can classify the device as “misbranded” and issue stop-sell orders. Some have already done so.

These findings will also be important for the class-action suit that has been filed against the company and its owners. I.e., because there is now peer-reviewed evidence that the device does not kill mosquitoes, it will be considerably easier to prove to a jury that the company’s efficacy claims are false or misleading.

Finally, the results call into question the efficacy claims of the company’s newest product, the Spartan Mosquito Pro Tech, which replaces sodium chloride with boric acid. Although a boric acid solution can certainly be lethal if mosquitoes ingest it, the Pro Tech is based on the same design as the Eradicator and thus would not be expected to either attract mosquitoes or to allow them easy access to the fluid inside. The Pro Tech label, however, asserts that the device will attract and kill mosquitoes. It would be great to get a third-party assessment of whether those label claims are true.

Testing the Eradicator and Pro Tech at home

In regards to the question of attractiveness to mosquitoes, consumers can easily assess that at home with a zoom-equipped camera, binoculars, or a security camera. The idea is to be able to see mosquitoes near the cap (if they are there) but to be far enough away so as not to distract the mosquitoes. Ideally, capture a photograph or movie and get confirmation of what insects are actually gathering around the device (again, if any).

Per the above paper, you likely won’t see mosquitoes gathering around the devices. Per the company, mosquitoes will gather around the devices.

People can also assess whether mosquitoes are entering the devices by dumping the contents onto a white plate and taking a photograph. Ideally, share your photographs on Spartan Mosquito’s Facebook page — they’d love to see them. Or post on them on Twitter and cc me (@colinpurrington).

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.

Tips

  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.

© 2020 COLIN PURRINGTON

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.