Mosquito Killing Ovitrap




Introduction: 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

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

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

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

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

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

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

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.

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!

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.

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292 Discussions

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.

9 replies

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!

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.

that would definitely not work. sunlight sterilizes water and also tap water is so clean even if you left it in a warm dark place for a month it would probably hardly smell. there needs to be something in it to rot like plant matter or as jmwells said dog food. personally i'd just leave some leaves or grass in a bucket of water for a few weeks

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".

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.

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 :)

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

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

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.

1 reply

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.

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

Glue in the bottom of the cup did not work for us. However, a few small stones works just fine.


Question 2 months ago

I built these traps, but the socks keep drawing the water up allowing the water to evaporate quickly. A full cup is gone by the next day. Does this system require building stagnant water and refilling the containers?

Does it have to be silicone glue or will any other waterproof glue work?