Introduction: Mosquito Killing Ovitrap

Picture of Mosquito Killing Ovitrap

This little device is cheap to create, and has been used by the US military on bases in malarial zones with fantastic results. There are many types of Ovitraps you can create, some are easier than others but require poison that is not readily available to a lot of people (like in Canada). This one does not require poison and works to effectively kill off the next generation of mosquito before they can bite you. According to some reports, after 6 weeks use this is as much as 98% effective!

I built each one of my traps for about .40 cents.


This trap IS like honey to mosquitoes. Avoiding the sweet smell of this natural trap is like asking a teen aged boy to not look at the hot girl in class, or a child to not eat a candy. Mosquitoes look everywhere for stagnant water with a moist dark area around it to lay their eggs. They do this in at least 10 different places in their short lifespan to increase the odds of their eggs hatching. The entire reason mosquitoes exist is to suck your blood and then turn that blood into eggs. Think how hard they try to bite you... once they're full of your blood they try even harder than that to find stagnant water.

Mosquitoes can't help but lay eggs on the moist black sock on the rim of this trap. Once those eggs hatch, their tiny larvae will crawl through the screen into the stagnant water below and eventually hatch into live mosquitoes that are just too big to get back through that screen. You won't notice anything in the trap for a while as this process takes a week or two to start. So keep the traps filled with water. After 6 weeks you should see that the trap has dead bodies under the screen. That means the mosquito genocide has begun.

From what I've read, you need 4-6 of these ovitraps per acre of property. Less for urban areas, more for rural ones. Once you see your traps are full, just pull the screen out, empty the dead bodies, then refill with stagnant water. They can be used indefinitely.

Step 1: Obtain Your Supplies

Here is what you need:

1. CHEAP plastic containers. The larger you can find the better. If you live in a sunny or windy area I recommend going with at least 4L or 1 Gallon containers. BLACK is best, but if you can't find black, you can either spray paint or fudge it later (this will be shown later in instructable).

2, Black socks. I got a pack of 20 pair at Wal Mart for 7$. They must be BLACK.

3. Silicone based glue, or just a tube of silicone sealant.

4. Metal screen (it MUST be metal). You local hardware store will have rolls for about 10$.

5. 18 or 20 gauge wire. Got mine at the dollar store.



Wire cutters



Step 2: Drill Holes in Your Container

Picture of Drill Holes in Your Container

You want to drill 2 holes in your plastic container. I couldn't find black ones, so I just used red.

Drill 1 small hole right near the top of your container just wide enough to fit 18 or 20 gauge wire through.

Directly below that hole, about 80% of the way up the container (20% down from it's lip) drill another 1/4" hole. This will be the water drain to ensure the water level never goes higher than the metal screen you insert in the following steps.

TIP: Brad point drill bits work best here.

Step 3: Glue Your Sock Into the Container

Picture of Glue Your Sock Into the Container

Now, put a dab of silicone or silicone based glue in the bottom of the container you have just drilled. Then take the toe end of the sock and press it to the glue.

You have to wait for this to dry so if you want to make a bunch of ovitraps at once, I recommend drilling and gluing every one of them at once to save time.

Step 4: Trace Your Container Onto Metal Screening and Cut It Out

Picture of Trace Your Container Onto Metal Screening and Cut It Out

While waiting for the glue to dry, start making your screens.

Using the top of one of your containers as a template, trace it onto your sheet of metal screening. I found chalk worked best for this, but anything you can see will work. If making multiple ovitraps, it is much faster to trace them all at once.

Once you have finished tracing your screen, use a pair of scissors to cut out nice perfect circles.

Step 5: Cut Yourself Some Wire

Picture of Cut Yourself Some Wire

While you are still waiting for the glue to dry start cutting some pieces of 18 to 20 gauge wire. The length is up to you, but I found a couple of feet is best and gives you lots of wire to work with later once you get to the hanging of your ovitrap phase.

Step 6: Glue Dry? If Not WAIT!

Step 7: Now Adjust Your Sock

Picture of Now Adjust Your Sock

Once your glue dries, take your sock and pull it over the mouth of the container and pull it around the bottom. Socks are incredibly stretchy and can be bought in many sizes so just stretch it over the mouth and around the bottom of the container. Trim any excess you have at the bottom (basically making sure the sock is taunt all around the container, but NOT super tight. That will pull the glue off eventually and also opens the weave of the sock a bit too much to the point mosquitoes may be able to get through and out the drain hole), then glue it to the bottom of the container.

By using a black sock and pulling it all the way around the container, I was able to get around the need for black containers. You could also just spray paint the container black if you don't want to do this.

TIP: If you live in a hot, dry, windy environment wrapping the sock all the way around the outside of the trap will increase evaporation which limits the trap's effectiveness so keep this in mind.

Step 8: Insert Your Screens

Picture of Insert Your Screens

Once the glue dries on the bottom of your container and your sock is nice and secure, carefully press the metal screen into the top of the container. The goal here is to press it in so that the deepest part of the screen is just above the height at which you drilled the 1/4" holes in step 1. This is a MUST as the way the ovitrap works is to allow tiny mosquito larva to crawl down through the screen to the water below, then later hatch, but get trapped beneath the screen because they have grown too big, and thus die/drown. If the water level is above your screen the trap will not function properly.

TIP: I found the easiest way to insert these screens was to gently press in the center, then carefully slide down 1/2 of the screen to the desired depth, then rotate the container and insert the other half the same way. This will result in a nice concave bent screen that creates pressure on the sides. The jagged edges of the metal screen will grab hold on the sock and keep it in place very well.

Step 9: Insert Your Hanging Wires

Picture of Insert Your Hanging Wires

Once all of your screens are in place, insert your 18 to 20 gauge wire into the small upper holes you drilled in step 1 on both sides of the container. Then simply twist the wires like a twist tie to keep them in place. This wire will be how you hang/attach your ovitrap later on.

TIP: If you have drilled your holes properly you can insert this wire through the container, and into the concave screen to help it stay in place. This is NOT necessary but is helpful for the longevity of your trap.

Step 10: Go to a Pond and Get Some Stagnant Water.

Picture of Go to a Pond and Get Some Stagnant Water.

Ok, now you NEED stagnant water. Mosquitoes like stagnant water more than your kids like sugar, they can't keep themselves away from it. Fresh water will NOT work, so make sure it smells rank.

Now, dip your ovitraps into the stagnant water and lift them out by the wire. Excess water will now flow out of the 1/4" holes you drilled to ensure the water level is always no higher than designed. If you water level is above the bottom of the screen you inserted, you did something wrong.

TIP: Add 1 or 2 pieces of dry dog food to the trap to make sure it stays stagnant even after a heavy rain (thanks to instructables for this tip!!)

Step 11: Hang Your Trap and Start Killing Mosquitoes!

Picture of Hang Your Trap and Start Killing Mosquitoes!

You're done!

Hang your trap wherever you want. Shaded places away from the wind and sun work best. Inside of trees, by shrubs, or in gardens are all fantastic places to put these.

Rain will continually help refill these traps so they will work until they fill with dead mosquitoes. However, if you live in a windy area, or place these in the sun, or have used a smaller container for your trap you may need to periodically refill the container with stagnant water to keep it wet and useful.

TIP: As discussed earlier, this trap will be like honey to mosquitoes. They can't help but lay eggs on the moist black sock. Once those eggs hatch, their tiny larvae will crawl through the screen into the stagnant water below and eventually hatch into live mosquitoes that are just too big to get through that screen. You won't notice anything in the trap for a while as this process takes a week or two to start. So keep the traps filled with water. After 6 weeks you should see that the trap has dead bodies under the screen. That means the mosquito genocide as begun.

From what I've read, you need 4-6 of these ovitraps per acre of property. Less for urban areas, more for rural ones. Once you see your traps are full, just pull the screen out, empty the dead bodies, then refill with stagnant water. They can be used indefinitely.

TIP 2: If you have access to mosquito poison, add a drop or two to the water inside of the ovitrap (make sure they are out of reach of kids or pets if you do this). The result of this will be that the mother mosquito that lays its eggs will fly off and die, thus making the trap work more quickly! The poison won't last long unless you live in a country with lax poison control laws, so you'll need to do this every few days for it to be effective. If you use poison, ensure the type you choose does not repel the mosquitoes or the traps will not work.

TIP 3: If you have garden LED lights, or fence post lights, put these traps under them. Mosquitoes get drawn to the light, smell the water and go in to lay their eggs. The more you attract, the faster and better these babies work!

TIP 4: IF you live in a rural area with a lot of land, AND have access to a long lasting mosquito poison you can make easier lethal traps. All you need is a black pail of stagnant water. Float a piece of wood, or a stick in the pail or even a piece of cardboard, then add your poison. Any mosquitoes that come to lay eggs die and so do their larvae. Unfortunately, most regions of the world have banned the best insecticides for this use because they last in the environment too long.


Blokhed1 (author)2015-06-20

What are the bigger holes for? M

jfulop10 (author)Blokhed12015-06-21

The bigger holes are for drainage. When it rains they could over fill causing the water level to raise above the wire screen and allowing the larvae to hatch and go free. If they weren't drilled there you'd essentially be making mosquitoes perfect little breeding containers :)

MarkM613 (author)jfulop102017-07-04

Can't these holes serve as escape routes for the hatched mosquitoes reducing the effectiveness of the trap?

OnAngelsBreath (author)MarkM6132017-07-04

The sock will be between the holes and the mosquitoes that you're catching. Re-read the instructions, that was very clearly stated.

jmwells (author)2015-06-19

Placing a bit or two of dry dog food in tap water will also work for those who can't find pond water. It just takes a few days to age.

JackG54 (author)jmwells2016-06-21

Thank you kindly! That was my first question, "There's no ponds within 20 miles of me! How can I make stagnant water?!?" My next step was Google! Thanks again!

ConnyJ1 (author)JackG542016-06-22

Wouldn't putting tap water be fine. I suppose you could age it by putting the water into a clear seeled container for a few days in the sun first, then put into the trap. But keep water seeled unless in the trap.

jfulop10 (author)jmwells2015-06-20

Thanks for the idea, that's awesome!! I updated the instructable with it.

On a related note, if you have standing stagnant water in your area that breeds mosquitoes you can also buy "Mosquito Dunks" on Amazon. They contain a harmless natural bacteria that selectively feeds on only mosquito and black fly larvae. They are environmentally safe and approved in all 50 states as well as every Canadian province. The bacteria in the "dunks" already lives in every pond you see, just in small enough numbers that they live in balance with the hatching mosquitoes. Adding the "dunks" is like dropping 10,000 wolves into Australia to kill all the rabbits... once the food supply is gone they all die. Then you just add more "dunks".

keonfan14 (author)jfulop102016-05-09

Home Depot has dunks also.

ringai (author)jfulop102015-07-10

Thanks for that tip. I'm sure grateful.

xenobiologista (author)jfulop102015-06-23

Yeah the bacteria is called Bti (Bacillus thuringiensis subspecies israelensis

I think you can also add some grass or straw to fresh water to make it go "stagnant" faster. I can't remember where I saw this but it was either in a scientific paper or some other technical resource on making ovitraps.

I can see the grass clippings working well. I occasionally forget to empty the grass catcher on my lawnmower and it becomes very pungent just with the moisture from the clippings in only a matter of days.

dockazoo (author)jmwells2015-06-23

Thanks will keep this tip in mind.

jfulop10 (author)2015-06-20

Since making about 10 of these 3 weeks ago my mosquito problem has already dropped about 75%. I live by 3 ponds, and a semi-dry creek so it's horrible here... an army of 20+ mosquitoes would attack the instant you opened any door at one time. Now I can go outside and in an entire night maybe see 4 or 5 total mosquitoes. I'm really hoping in a few more weeks the problem will be gone altogether. My biggest problem is it's VERY windy so I need to refill the traps every few days. What I've found is in the traps that stay full I get dead mosquitoes. In the ones that dried out at one time or another I see tiny almost sand-like grains in the bottom. Those are the larvae that died when the trap dried up. So if anyone sees no adult mosquitoes in it and they have dried at one time, don't give up it's still working just not as well as they would if kept full.

jfulop10 (author)jfulop102015-07-02

I'm entering week 5 of my Ovitrap experiment here and finding I NEED to refill my smaller containers every couple of days because of the wind and wick effect of the socks. They work *fantastically* when kept full but not when they dry out. The difference is unbelievable when I'm diligent. I HIGHLY recommend larger containers. I'll be making some larger ones shortly using 2L pop bottles with the same design. When I do I'll update this Instructable. I'm also going to try using 30L buckets with a floating screen with a rim of wood to float it. Once I figure out how to make it easily and cheaply I'll add that as well. It would be nice to set those up and forget about them for a few weeks at a time or more.

seamster (author)2015-06-19

This is brilliant! I need to make a few of these. Thank you very much for sharing this idea!

Swansong (author)2017-10-13

We need something like this here! The mosquitoes were so bad this summer. >.< Thanks for the idea :)

rampras (author)2017-08-30

Hi I am sorry to ask you a laymans question... How can mosquitoes lay eggs when water is not directly accessible to them... or how can mosquitoes access the water for laying eggs.. as there is a metal mesh?

procter (author)2017-07-05

Well done instructable.

The Mosquito Economics is a concern. What you are essentially enabling is the breeding of mosquitoes in order to kill them.

This seems to me to be fundamentally unsound.

Given: "Female mosquitoes can lay a set of up to 100 eggs about every third
night after mating only once. They typically lay as many as three sets
before dying.

I think that a sound economic strategy is to kill them before they lay eggs, given they can lay more than one set of eggs, and they may not lay them all in your Ovitrap. Forgive my scepticism :-), and keep making great instructables.

FirstnameL6 (author)procter2017-07-08

Yes, it would be nice to kill them before they lay eggs, but that's difficult to do in great numbers without lots of poison. That's why we still have many areas with bad mosquitoes. Which is why these traps are made. They aren't "breeding mosquitoes in order to kill them," as you say. That makes it sound like these traps are increasing the population, then trying to kill them.

These traps are eliminating populations before they get a chance to exist. The eggs never fully mature. Yes, an adult female might lay another set of eggs somewhere else. But the ones she lays in this trap never mature. So the overall population is reduced from what it would have been.

MaryP6 (author)2016-06-20

I use DDT from an old glass gallon bottle my grandpa had lying in the basement, put it in a sprayer dilute it and it works great

Nana2Peanut (author)MaryP62016-06-26

This very destructive, toxic chemical was banned
because it was causing wild bird egg shells to thin to the point of
complete instability. One of the birds most affected was the Bald Eagle.
Banning DDT has been one of the major factors in bringing eagles back
from the brink of extinction. So, please, take this to your toxic waste disposal site tomorrow and never use another drop. PS It's harmful to humans, too.

MaryP6 (author)Nana2Peanut2016-06-26

I know, your 100% correct.

RickS133 (author)MaryP62017-07-05

An activist wrote a book that said the bird eggs were make thinner (Rachel Carson - Silent Spring). To my knowledge, there was never a scientific study done to prove the effects.

michaelmacnz (author)MaryP62017-07-05

you are not the only one... I was cleaning out some ols stuff when we were moving house a couple of years ago.. In my Electrolux collection (vacuum cleaner) was a glass/Pastic bug sprayer AND a screw cap metal container (from the late 60's ) of "insecticide" guess what...DDT.. yes i disposed of it properly. However although is proved to be REALLY bad... it was the miracle for our guys in WW2... These days we don't see a lot of lice and fleas on a day to day basis.... those days were different... BTW.. more people died of The Spanish flue than died in conflict in WW1.... Life is a journey~~not a destination

smirlex (author)MaryP62016-06-23

DDT worked very well,killed every bug, & lasted forever & thinned the shells of the birds up the food chain, so much that they couldn't support themselves. Notably, the hawks, eagles, etc. Almost making them extinct. It was outlawed many years ago. The eagles are just now coming back. (Sorry if someone has already mentioned this)

Please find a good way to dispose of this safely & don't use it.

tkjtkj (author)smirlex2016-06-25

I think the reason for DDT being illegal in USA was cuz it was causing bird egg shells to be VERY thin .. killing birds, not cuz it wiped out their food supply ..

It's a terrible chemical ...

ref: Rachel Carson : " Silent Spring"

OnAngelsBreath (author)tkjtkj2017-07-04

No one said it wiped out their food supply...they said the harm continued right up the food chain!

sarawelder (author)MaryP62016-06-24

please do not use DDT... it is very toxic to everything.

sarawelder (author)MaryP62016-06-24

please do not use DDT... it is very toxic to everything.

sarawelder (author)MaryP62016-06-24

please do not use DDT... it is very toxic to everything.

MasterJoe (author)2017-06-16

Forgive my ignorance if it applies....Don't mosquito's lay their eggs on/in water? If so, how does the adult female get to the water if the screen is in place? If not, please clue me in.

cygnosis (author)MasterJoe2017-07-05

Actually, a recent study* shows that most of the mosquito species in the study will lay their eggs on a solid surface near water most of the time.

* Erik M. Blosser, Nathan D. Burkett-Cadena. "Oviposition Strategies of Florida Culex (Melanoconion) Mosquitoes." J Med Entomol (2017) 54 (4): 812-820

MarkM613 (author)2017-07-04

Sorry.... I did realise and I deleted my comment. What I cannot appreciate is that the mesh is above the water. Will the larvae actually drop themselves into the water?

A longitudinal cross section diagram of the trap would help visualise better the way it is constructed.

MolnarL1 (author)2017-07-04

Hm sounds tasteful. Added to todo list. Thank you.

pjgardens (author)2016-08-25

I have a birdbath that I have to keep an eye on, dumping it regularly. If I attach screen over the top would that do the same thing?

OnAngelsBreath (author)pjgardens2017-07-04

If you put a screen on top, the birds couldn't bathe in it. I have a birdbath that is very busy all summer long, birds & bees are drinking from it and the birds will at times be up to five bathing at once! I have a hand scrub brush (that I only use for the birdbath) and every night, after dark, I dump the bath, scrub it out, rinse it and fill it with fresh water for the next day. If your birdbath is producing mosquitoes the birds probably aren't getting much use of it anyhow and maybe you should just consider not having open stagnant water sittting around your yard. The birds appreciate clean water.

Korishan (author)2017-07-04

I know it's been a long time since some of the comments, but I love this idea. We have loads of mosquitos here that will even come out in the full blown sun. And, they can tap through jeans!

Going to my local hardware store to get some dunks as well, as we have several ponds and creek/ditch/river through the middle of our property (30+acres)

An idea to the sock drying out due to wind:
1) How about instead of putting the sock "over" the top of the container, take some glue as you did earlier and line the inside edge of the container at the top, place the sock over the lip and put another (in the case of the cups above) cup inside to allow the glue to adhere to the sock to the wall of the cup. Then cut the excess off the top.
2) Take the cup and place it inside a larger cup so it's down out of the wind and put some holes in the bottom that one. This also has the added benefit of being able to use long nails to hold the cup in some high grass/weeds and hold the smaller cup inside. You could even add a lid somehow to make it dark inside.

jim_lewis1 (author)2017-07-04

Re tip 4. Please do not leave pails of poisoned water around. Any animal could drink it, probably someone's dog.

BCMP made it! (author)2017-06-21

I used 3" PVC about the length of a sock, it holds more water. I only folded the sock enough to hold it on. The more sock that is exposed on the outside, the more the water evaporates. I grabbed some dried grass clumps from under my lawnmower to get it ripe.

KevinD170 (author)2017-06-08

Hi, I made 2 ovitrap 2 weeks ago. Thanks for this nice instructable. For now it doesn't seems to work. But I realized that having the sock all around would drained the container to fast . After 1 or 2 days the ovitrap is empty and the sock is dry. I dont live in a windy area and the temperature was not warm at all (15 celsius). To improve it, I cut the sock to leave only a little overlap on the outside of the container (1 inch). I used black duct tape to make my container black. It works better this way with a LOT LESS evaporation.

But still I have a question, why would mosquito prefer my ovitrap instead of my dirty neighbor clogged gutters ? Is there a way to attract them in my ovitrap ?

keithwd (author)2016-12-06

Try using boric acid or laundry borax in the water for a poison to kill the larva. The amount required to kill insects is "far" lower than the amount needed to damage, much less kill animals--birds are almost immune to it due to how their kidneys work.

You will have to experiment to find the best dilution ratio to use. Too strong and it could repel them, too little and it would not work.

My recommendation, is to start off with a saturated solution (no more will dissolve and some powder is left in the bottom of your mixing jar). After you have the saturated solution use it to calculate the ratio of it and water. I suggest you start out with a 50% water and 50% solution, and raise the percentage of water if it seems to repel the mosquitoes until it does not repel the gravid mosquito but still kills the larva and eggs.

Another experiment would be to see if you could get the correct ratio to where the mosquitoes would still lay their eggs on the fabric but it would kill the eggs either before they hatched or right after, and hopefully kill mama shortly afterwards...


carl5blum made it! (author)2016-08-22

Hi Gang:

I made six of these for around the house. If I make more I will skip the glue and use a short cross wire to hold the sock down.

( The Palmetto Bug Stomp is our local dance weekend )

Thanks, Carl.

Wolfrick (author)2016-08-17

Seems to me that a disc above the trap would create shade and make the trap more enticing. If you made the disc very wide and funnel-shaped, it wouldn't block rain refilling the trap for you, and by shading the trap would make it lose water to evaporation more slowly.

SurendraV2 made it! (author)2016-07-17

I used a rectangular container with little tweaks. The holes for water overflow is little tricky.. it has to come below the mesh.. so i had first installed the mesh then marked the lower end of the mesh on the container and removed the mesh and made the holes..then fixed it back and the water level came just below the mesh..

queenopearls made it! (author)2016-07-17

With 4 traps (16 ounce cups from Walmart) around a typical suburban yard size but with many, many bromeliads, the mosquito population has dropped to the point I don't swat hardly at all. I have no way of quantifying the number of mosquitos. That said, this frog has taken up residence on one of the traps. Apparently there are enough mosquitoes to keep the frog fed. Or so I would like to think. :)

kip1222 (author)2016-07-09

I'm actually in the process of make 4 of these right now. I do have a question. Riight now i'm using cups similaur to what you used so socks aren't a problem. If you use a bigger container like a 2L bottle, paint it black, but what about the sock? Do you still use it? How would you attach it? Let you know how these work. Thanks!

MorcoPollo (author)2016-06-19

This is a bit backwards and antiquated. the female mosquito looks for water AFTER she has sucked your blood (and possibly transmitted deadly diseases into your bloodstream.

One needs to get that mosquito into a tap BEFORE sucking your blood. In order to do THAT you need to know how they hunt you down. It is does by CO2 that you exhale. So, get a CO2 based mosquito trap in order to keep from getting bitten in the first place.

nanaverm (author)MorcoPollo2016-06-19

Fermentation produces CO2 - try using rotten fruit or even yeast with something to feed on. Rotten bananas really created a buzz for the mosquitoes outside my house.

Cyberchipz (author)nanaverm2016-06-19

Perhaps I'm wrong about this; but, I heard that it's the male mosquito attracted to the fruit; so, not necessarily killing them as they don't lay eggs. On the other hand, having both sexes at the same watering hole might speed up the process and ensure the trap is nearby for laying eggs!

I had a CO2 trap years ago, and until it stopped working. My yard was close to mosquito free (3/4 acre) per tank propane/2 mo (~$7.00/mo). So, not environmental, not cheap; but, very very effective. Took about 2 months to clear yard, the next year I used attractant, and cleared the yard quickly. Kept the trap about ~10 yds from ditch at back of yard, and ~20 yds from house.

Got to try this!

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