Introduction: Plastic Bottle Mosquito Trap


Hello dear friends!

As some of my followers already know, I live in Bologna (Italy), in the heart of Po river Valley.

This area is known as the wettest one of Italy. This is due to terrain, level (a lot of areas are UNDER sea level) and weather.

These factors result in very hot temperatures in summer, very cold ones in winter, an incredibly thick fog but, mostly, giant and aggressive mosquitoes.

There is a city, Comacchio (only 55 miles from Bologna), that is known as the "Mosquitoes Town". XD

Obviously is nothing tropical, but it's very annoying!

It's really difficult to enjoy summer evenings without using pesticides, sprays or other stinky poisons. Or, you can always avoid using anything and... be eaten alive by these little vampires.

While mosquitoes are useful for the ecosystem (did you know that mosquitoes are the main cocoa plants pollinators? No mosquitoes means no chocolate!!!), we don't want them to fly around our garden and bite everything that's alive, pets included.

In this Instructable, I want to show you an all natural and potentially free way to create an efficent mosquito trap with little more than a plastic bottle!

Why potentially free? Because we will use materials that are always present in our home!


Let's start with our shopping list.

Step 1: Shopping List

For our trap we will need:

  • Plastic bottle (2 liters one is good)
  • 4 spoons of white sugar
  • 10gr (0.70oz) Brewer's yeast (freeze-dried one or fresh)
  • 200ml (6.75oz) water (and a pot for boiling)
  • Tape
  • Black cardboard (or similar dark covering)
  • Scissors

Optional for hanging

  • String
  • Liquor can container (like Baileys one, look at the images for more info)
  • Drill

If you have the liquor can container, you won't need black cardboard, we will see why.

NOTE: A lot of users reported me different results. Someone have found a full trap and some other an empty bottle after several attempts. You should experiment a bit by changing the amount of yeast in each traps, in fact only some kind of mosquitoes are attracted by this trap and the amount of CO2 released change the effectiveness depending on climate/humidity of your zone. For example, I've found a full bottle on the first attempt and much less dead mosquitoes in the next two bottles (with same recipe). I'm experimenting different mixtures in these days ;)

As you can see, these are very common and easy to find materials.

I didn't have to buy anything except for the brewer's yeast (I can't find fresh one...darn).

Let's move on the first thing: cutting the bottle!

Step 2: Prepare Your Bottle

The first thing to do is cutting your bottle at the right height.

You have to cut 2-3 cm (about 1 inches) over the point where the bottle becomes thinner (the grip).

Use your scissors for that, or a Dremel if you have one! :)

You don't need to be super precise, but try to make a straight cut.

Now you have 2 separated pieces.

Easy, isn't it? :)

To the mixture!

Step 3: Mixture

Now, put 200ml (6.75 oz) of tap water in a pot and boil it for 10 minutes.

This will eliminate the possible presence of chlorine.

Don't boil more thank 10 minutes, or too much water will evaporate.

While water is still hot, add 4 spoons of white sugar and mix until everything will be dissolved.

Now wait until water is at room temperature.

It's important, or high temperatures will kill the yeast and deform the plastic bottle.

Then, pour the sweety mixture in to the big part of the bottle (obviously).

Finally, add the brewer's yeast.

Don't mix yeast! If you do so, the reaction that attracts mosquitoes will NOT last longer.

Now that the mixture is ready, put the top part of the bottle inside the big one, face down, to create a funnel (the picture shows it well).

Finally, close the border with some tape to fix it up and make te cap hole the only way in-out for mosquitoes.

I've used black tape for electrical work, it's good for this kind of fixing.

Step 4: Prepare for Hanging

This step is optional, but I highly recommend it.

You can finish now your trap by wrapping the bottle with black cardboard to add a sun protection (not from the heat but from UV).

But, if you want a more stylish solution, I suggest the use of a liquor can container (the Baileys one is very popular).

Use a drill to open two holes near the top of the can, in opposite directions.

This holes will be used to create a knot with some string and use this can as a "hanging bottle container".

You will have a easy and quick way to change bottles without the need to take them down from hanging every time!

A bottle case ;)

Plus, this covering will protect the bottles from UV sun rays.

Finally, you won't have to make holes on the bottle surface, making some precious CO2 to go outside (next step to discover why!)

Step 5: Ready for the Hunt!

Now make a knot in the other hole of the can and hang your trap outside!

In your garden or in your balcony, the best place is a dark and humid one, not exposed to direct sunlight.

But, how does it work?

The brewer's yeast produce a small but continue amount of CO2, that, mixed with the high sugar amount in water, creates a smell that is irresistible for mosquitoes!

So, these little devils fly inside the small hole of the bottle cap and get stuck, with no way out except for the hole itself. The percentage of mosquitoes that fly out again from the trap is ridiculously low.

The cover (black cardboard or the can) prevents UV rays from killing yeast and stopping CO2 production.

Also, we use tape around corners to prevent CO2 from going out from the bottle in "high" quantities.

The amount of yeast (10gr) last for about 2 weeks.

After this time, you will have a bottle full of mosquitoes! :D

You can clean it and fill it with new mixture, or prepare a completely new one.

With the quick change hanging system, it will be easy to have a new trap in minutes! :D

You now have a 100% natural and green trap, with zero amount of poisons or other harmful chemicals!

Hope you'll like and help you from getting bit ;)

From Italy, this is Filippo

Ciao a tutti!


AndyMoore made it!(author)2017-06-18

Made a variation without the protective cover (just used some old masking tape). Great idea and quick build. So far, not catching any mosquitoes, but will be interesting to see what I catch. Thanks!

FrugalNana made it!(author)2017-06-04

I am new, 64 and have a large infestation of mosquitoes. I have a stagnant creek behind my land. The comments are very good and I'm grateful for your tips. A few things for sure work well. Catnip is a of the mint family. I have made a spray with it, I added alcohol, so .. Even by rubbing it all over my skin and and clothes works awesome!. This has been very successful! All mints are great. Lemon smells work well too. I have onions and garlic growing also in my garden. If there's a mosquito, it finds my family. I plan to use the bottle tip. Many say it works. I love the fan too. I have seen a screen put on the back of the fan to catch them. Spray them withalcohol to kill them.. Hope this helps you.

Bhenley3 made it!(author)2017-05-07

High winds like a fan is the only way to stop them from sucking your blood. Point it right on you and enjoy the outside in that one local spot. Nothing will work except for this.

katbow made it!(author)2017-05-08

Actually, you can keep them from even wanting to land on you, by eating raw onions...I've been in clouds of mosquitoes after eating a sandwich with a large, bread sized slice of, sweet purple onion. Everyone else was covered in bites but I didn't even have one.

OculumForamen made it!(author)2017-05-11

A friend oof mine used to take Garlic capsules, one every day during insect season, and he swore by it, and I did notice that he suffered FAR fewer bites than I did, when we went fishing. I live in Canada, and I can tell you that the Mosquitoes in the North are the territory's official Bird! We tried to use AA installations to control the Mosquito population, but last year they flew off with one of our guns, so we have abandoned this idea! LOL Seriously though there are a number of herbs that work as a mosquito repellant. The most powerful of them I have heard, is actually Cat-Nip! If you own cats, though, that would be a serious problem. Cat-nip in it's concetrated form, is on order of 100X more effective than DEET!

sleeepy2 made it!(author)2017-05-29

No, I grew and used catnip. DEET is much more effective.

OculumForamen made it!(author)2017-05-30

Yes, actually. Google it. Catnip contains nepetalactone, which is 10 times more effective as a mosquito repellant than DEET. DEET disolves car paint! I used it every day when I was a teenager riding with my dad for work, and it softened the paint on the inside door sill where I always rested my arm, to the point I could scrape it off with my fingernail and it would take it right down to the metal! If you use a lab still and a hydro bath condenser, you can harvest the oils from the cat nip, and add it to a cream or a water spray and use it that way. Just growing catnip and rubbing it on yourself will not work. It's really not that hard, you just need to know the basics and have the components for a lab still. :)

ZacharyD41 made it!(author)2017-05-24

The joke in maine is our other official state bird is the mosquito lmao

CindyL2 made it!(author)2017-05-12

Well, onion didn't work for me. Neither did garlic. I have tried numerous ideas. I am a mosquito magnet. I will try this on my porch. If nothing else, I can enjoy some Baileys.

jim1824 made it!(author)2017-05-09

Actually, I think eating a raw onion will keep everyone and everything away.

PattyP17 made it!(author)2017-05-10

LOL! Thumbs up.

w6pea made it!(author)2017-05-16


I sure hope this works

JumpingThrghHoops made it!(author)2017-05-14

So just to complicate things lets say the people with the CO2/tube idea use the tube and insert a needle into their own arm, and take their own blood and let it slowly drip into the bottle trap while watching t.v. Yes, that sounds right. ;-)

gavinnn made it!(author)2017-05-13

No worries dcp123, it was totally self-motivated :) I live near water and my wife attracts more mosquitos than most traps do, so I'm always on the lookout for solutions!

gavinnn made it!(author)2017-05-07

The most you can hope for, even if you fill your trap 5 times a night, is a warm feeling of revenge. As another poster said, there are billions of mosquitos, especially in your area, and your trap will not change the number of mosquitos landing on you - at all. Not criticizing, like your idea - easy to make and clever - just trying to add some perspective.

dcp123 made it!(author)2017-05-07

I could be wrong, but I don't think that's entirely correct. It is my impression that most mosquitoes don't travel far from where they hatch. If I'm right about that, you should be able to reduce the local population density around your house.

gavinnn made it!(author)2017-05-07

I did a bit of reading and this informative faq from the American Mosquito Control Association (Note: How far can mosquitos fly? What can homeowners do to reduce mosquito bites? and Are backyard systems effective? among others). It seems mosquitos ranges vary quite a bit, many around 150m according to the first article and up to, with some exceptions, around 11km (7mi). Hatching areas near the house do seem to provide many of the mosquitos we deal with, though, so it's worth dealing with them. The original poster is located not far from the massive swamps south of Venice, so he's prolly better off using barriers or repellants.

dcp123 made it!(author)2017-05-13

Thanks for doing the research I was too lazy to do. My prior understanding and experience with mosquito attacks near breeding locations is more consistent with few ranging more than 150 meters, but I have done no reliable studies and as your research indicates, it would not be at all surprising if their range of travel varied hugely. Also, as you point out, if some one is in the area of a massive mosquito source localized trapping will be less effective than if they have small sources nearby.

qb8546 made it!(author)2017-05-07

This week I looked into a professional service. They said mosquitos travel up to 100 yards. That means the source can be somewhat far away.

CarolM131 made it!(author)2017-05-07

Fruit flies love this also. In the U.S. we call this yeast Baking Yeast. Great idea- thank you!

CindyL2 made it!(author)2017-05-12

Actually it's not Baking Yeast, they are two different products. Baking yeast is used to rise bread, Brewers Yeast doesn't, I use it a lot for cooking, kale chips, sprinkle on pop corn. I love it. They are related, but brewers yeast is in a different "state", the live yeast has been dried and deactivated. So anyone with Candida problems should be able to use Brewers yeast without a problem.

I live in the US. Any store should carry it.

PattyP17 made it!(author)2017-05-10

I've successfully used apple cider vinegar in a trap like this for fruit flies and gnats. Fruit flies like bananas a lot too. And old saying:

Time flies like the wind. Fruit flies like bananas.

tnormandale made it!(author)2017-05-07

Nice idea. I have actually found an effective control for mosquitoes is a large half wine barrel full of water. This attracts them, they lay their eggs their and when it is thriving with larvae (about once a week) I hit it with a dose of hypochlorite (about a third of a cup of the dry powder for chlorinating pools). This kills off the whole batch of larvae. I have only seen two or three mosquitoes all summer, compared with previous where twenty to thirty would attack you every time you went out of an evening to water the garden.

kz1 made it!(author)2017-05-08

I had a large plastic tote with 200+ gallons of water I used for electrolysis. Skeets love it when the current wasn't running through the water. Let 'em lay their eggs and hatch into wigglers, then turn the current back on. Given a whole new meaning to the term wigglers! :-)

GuyB12 made it!(author)2017-05-12

> kz1


Definitely the funniest reply yet. Good to see you are in touch with the vicious side of nature. Gotta try this myself.

JerryK48 made it!(author)2017-05-07

Teaspoons or Tablespoons ?

kuma.rhyu made it!(author)2017-05-07

Probably teaspoons, but the proportions are not critical for this mix. The sugar is a food for the yeast to produce CO2 and attract the mosquitoes, making them think they are around a breathing mammal and a blood meal. If your trap does not produce well, try adding a little more sugar to the mix.

JerryK48 made it!(author)2017-05-07

I heard brown sugar works well because it's not refined

PattyP17 made it!(author)2017-05-10

Brown sugar is white sugar with molasses added back that was removed when refining the sugar.

JerryK48 made it!(author)2017-05-11

Thank You

BarrieT1 made it!(author)2017-05-07

I believe you will find that brown sugar is refined, but has added colour, so its effect would not be much different.

JerryK48 made it!(author)2017-05-08

thank you

SabrinaB38 made it!(author)2017-05-07

Not regular brown sugar, because as BarrieT1 said, it is refined sugar that has small amounts of molasses added to it which makes it brown. However, there is a brand of sugar called Sugar in the Raw, which is unrefined or minimally processed cane sugar. Its crystals are larger than regular sugar, and those crystals ARE light brown in color. Perhaps that is the type you've heard works better.

JerryK48 made it!(author)2017-05-08

thanks for info

KevinJ142 made it!(author)2017-05-07

Got a better idea, Use the same trap but only a lil sugar and water. have a tube coming from inside your house that air or basically Carbon Dioxide will flow into the middle of the trap. So instead of wasting yeast, they will be attracted by the real stuff. Put a screen or like a filter so only CO2 comes out of your house but they dont get in.

DarrenO2 made it!(author)2017-05-07

KevinJ142 - Can you make an instructable showing what you are saying? It sounds good but I need more info.

KevinJ142 made it!(author)2017-05-07

Just build it the way he showed you, add a lil sugar and water at the bottom.

Take like a rubber gas line, make a hole on the side about 2 inches up from the water. Hot glue a piece of screen over the bottle end and then glue the tube into the bottle. The other end has to go into your house somehow. Your house is filled with CO2, so when it escapes thru the house and out the top of the bottle, the mosquitos will go in the trap but are stupid and don't know how to get out.

the+norm made it!(author)2017-05-10

I think it would be easier and cheaper to get the yeast and forget about making holes in your house.

KevinJ142 made it!(author)2017-05-07

I'm not sure it will work, just thought of an improvement

PattyP17 made it!(author)2017-05-10

Not very workable as you would have to be able to collect concentrated carbon dioxide to funnel it outside. Sounds like you would have to build a carbon dioxide concentrating machine. The whole point is to build something simple, cheap and quick that works with little expense or effort.

Prof.+A.+Z.+O_Trope made it!(author)2017-05-07

Very interesting trap and discussion. One way to make a quick test would be to waste one bottle of soda. Just keep it cold, open carefully, don't shake it up, cut off the top, flip it, tape it, and put it outside in a cool place. Maybe wrap with damp cloth to prevent it getting too hot. The soda will slowly release CO2, definitely for less time that the sugar / yeast approach described here, but maybe enough to see if it will work in your yard on "your" mosquitoes.

The "billions of mosquitoes" and "do they just draw more mosquitoes" questions could probably be answered by trying out various numbers of traps in various positions, times of day, etc., and perhaps by comparing "baited" traps with results from unscented "no-pest" strips.

Maybe try this . . . on two successive days / nights, under similar conditions at similar times, etc. . . . First, just go out and sit or have a meal around your outdoor table. Bunch of people, breathing out CO2, attracting mosquitoes. Hang a half-dozen or so unscented no-pest strips right over the table, right in the environment where you are sitting. Afterwards, count the bugs on the strips, and, if applicable, the bites on you and your guests.

Then, on the next day / night, do everything just the same, but with several CO2 traps laid out around the perimeter of your outdoor area. If the traps are really capturing a significant # of mosquitoes (without drawing a billion additional ones from the whole neighborhood), you should find fewer mosquitoes on your no-pest strips, and fewer bites on you and your guests.

(Conditions will probably not be 100% repeatable, but if there is a really significant effect, it should show up.)

Nice 'ible!

PattyP17 made it!(author)2017-05-10

Actually, from my experience, sodas that had been opened even slightly go flat very quickly.

Prof.+A.+Z.+O_Trope made it!(author)2017-05-10

Well, it helps if you keep the hole very small, and as I said, make sure not to agitate it either before opening or after. I've had fast-food soft drinks stay reasonably fizzy in the fridge for several hours. Maybe if you made the entrance a "dip tube" like the straw in a cup of soda?

There are also ways you could increase the back pressure, like forcing the soda to work against back pressure. Say, a 2 liter soda with a tiny pinhole in the cap, then put a 3-foot piece of hose over the cap and fill it most of the way with water. Then the soda would have a few feet of water pressure to work against, and it would go flat more slowly.

Anyway, it would only need to work for a few hours to either prove or disprove the theory for a given person's yard.

Maybe vinegar in one container and baking soda in water in another, with one dripping slowly, drop by drop into the other? That would give off CO2 slowly, too.

JamieW104 made it!(author)2017-05-07

Looks interesting and definitely worth a try! Will it work on midges?

PattyP17 made it!(author)2017-05-10

I've used apple cider vinegar in traps like this for gnats, so it may work for whatever fly a midge is.

JoS86 made it!(author)2016-10-07

Hi, I don't have any sugar in the house. Do you think honey would work as an alternative?

AnAmerican made it!(author)2017-05-07

I could just prick my finger and squeeze the blood into the bottle - they seem to love that.

PattyP17 made it!(author)2017-05-10

"I could just prick my finger and squeeze the blood into the bottle - they seem to love that."

Best comment yet.

SeanFeeley111 made it!(author)2017-05-07

To paraphrase Boris Karloff, "Thank you for the blood, I never drink wine". What a clever idea you have, and please excuse my Dracula reference. Actually bats consume vast quantities of mosquitoes. Though it takes a while to attract bats, properly constructed and placed bat houses are incredibly effective.

KennethR14 made it!(author)2017-05-08

Bats actually mostly eat moths - not mosquitos. Studies have shown that ess than 1% of a bat's diet is mosquitos.

About This Instructable




Bio: Hi everybody! I'm Filippo from Bologna, Italy! My friends call me Orso (Bear) :) I follow Instructables since 2009, and it has always been one ... More »
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