Mosquito Bucket of Doom

Mosquito season is here! Instead of spraying pesticides onto our entire yards—and onto fireflies, ladybugs, bumblebees, and butterflies—why not just kill mosquitoes?

But wait, first: let’s PREVENT mosquitos from breeding in our yards. Here’s an infographic (link) from the CDC to remind us of the free and easy common-sense ways to do this, like removing standing water in toys, saucers and gutters.

And then, why not try a Mosquito Bucket of Doom?
It’s cheap, it’s safe, it works.

“Mosquito Bucket of Doom” is my name for the old BTi bucket trick, which I’ve known about for years.
I finally made one last spring, after I watched a 1-minute video from Doug Tallamy on his website (link) Do take a look. He’s an entomologist, and very convincing.

It’s just a bucket of water +
handful of grass +
a BTi dunk.

How it works:
The grass in the water rots and attracts mosquitos ready to lay eggs, but the BTi dunk in the water kills the larvae after they hatch. No adult Mosquitoes will emerge.

BTi is a larvicide targeted for mosquitos. It kills the larval stage (not the egg or pupal or adult stages).

“It kills the babies!” said a neighbor, who is now making a Mosquito Bucket of Doom of her own.

BTi will not harm anyone else. Lightning bugs, butterflies, frogs, mammals, etc. are safe.

How long with a dunk last? One dunk treats 100 square feet of water for at least 30 days, says the package. Well, my bucket has less than 2 square feet of water, so in my trials, I cut one dunk into 4 parts. Each 1/4 dunk lasted over a month, but I kept adding a new 1/4 each time.

(It’s honestly easier to throw a whole dunk in. They aren’t expensive. Sometimes, the lazy way is the best way.)

How much water? Fill the bucket only half full. Some mosquitoes lay eggs above the water line, and they won’t hatch till submerged with rising water, so they need room for this to happen. We want those eggs to hatch in the bucket, not outside on the ground. If rain can’t reach the bucket, add a bit of water every month (when you add the next dunk-chunk) to compensate for evaporation and to submerge any eggs stuck to the wall. (Some mosquitoes lay eggs directly on the water and are visible as small, black, rafts.)

Did it work?
Yes. At each check, I found newly hatched larvae/ wrigglers, but I did not find pupae / tumblers—the next developmental stage—which indicated that the mosquitoes died as larvae.

to maximize DOOM and minimize collateral damage:

Escape Ramp:
I add a stick as an escape ramp in case anyone other than mosquito fell in. I don’t want a chipmunk or lightning bug or even an ant to drown. See below for Child Safety Warning.

CHILD SAFETY: If there is the remotest possibility that a small child will ever be near your bucket, you must *securely* cover the bucket with chicken wire or hardware cloth.
“The U.S. Consumer Product Safety Commission (CPSC) warns that buckets filled with water or other liquids, especially the large five-gallon size, present a drowning hazard to small children.”*

Floaters vs Sinkers:
BTi dunks float—a good thing if you are monitoring it to see how long they take to dissolve—but I wanted mine to sink. I didn’t want the dunk to get taken by a curious squirrel or crow or the dog. If you don’t drill overflow holes in your bucket, the dunk might also float right out into the yard during a hard rain.

To make a Sinker:
I take an old onion bag—the mesh that onions are sold in—and tuck my dunk inside along with a small rock. I twist-tie this to the bottom of my Escape Ramp Stick.
When I need to check the dunk, I pull the stick up and look.

Cover Option: A layer of chicken wire or wide-mesh hardware cloth can keep the dunk from disappearing. Don’t use fine screening that mosquitoes cannot pass through.
**CHILD SAFETY: If there is the remotest possibility that a small child will ever be near your bucket, you must *securely* cover the bucket.
“The U.S. Consumer Product Safety Commission (CPSC) warns that buckets filled with water or other liquids, especially the large five-gallon size, present a drowning hazard to small children.”*

Color Option:
Colors attract mosquitoes AFTER they’ve detected the carbon dioxide that we exhale, and that our Buckets of Doom off-gas. The smell is enough, but adding color could help. But which color?

Black has long been considered an attractive color for mosquitoes, and a recent article (linked below) confirms this, but also tests other colors. Winners are black, red, orange, cyan. High contrast is also good.

“We find that CO2 induces a strong attraction to specific spectral bands, including those that humans perceive as cyan, orange, and red.” (link to study.)

To me, this means that the obnoxiously orange Home Depot buckets could be ideal.

And, it means that UT Vols fans, whose orange is even more obnoxious, must get a lot of bites on game days.

What if:
an entire neighborhood decided to forgo expensive and deadly pesticide foggers / barriers / yard sprays and opt to try the Mosquito Bucket of Doom?
Imagine how many more fireflies and butterflies and bumblebees and birds we’d have!

Please let me know if you’ve tried a Bucket of Doom, and if you’ve discovered any improvements.

-Video of Doug Tallamy on the BTi bucket trick: link.
-Xerces Society: “Protecting Pollinators from Pesticides:” link.
-“What you need to know about BTi” from the CDC: link.
-Mosquitos and colors study: link.
-Child Safety quote about buckets in general is taken from this link.
-Disclaimer / Use at Your Own Risk / info from SidewalkNature: link.


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Joanna Brichetto is a naturalist and writer in Nashville, the hackberry-tree capital of the world.
She writes about everyday marvels amid everyday habitat loss, and her essays have appeared in Creative NonfictionBrevity, Fourth Genre, Hippocampus, The Hopper, Flyway, The Common, Stonecrop Review, The Fourth River and other journals. Her almanac of local urban nature stories is forthcoming.

18 thoughts on “Mosquito Bucket of Doom

  1. You are a GENIUS! I’m sending this to everyone I know, esp in this neighborhood!

    1. Good, “no-brainer” info! (Having used dunks in stock tanks for years, I thought this was common knowledge. And cattle, horses, and sheep leave hay bits in the the water- so no grass addition needed 🙂)

  2. Dear Mosquito Jo,

    Thank you for your very interesting post concerning the mosquito bucket of doom. I hope a lot of people give it a go and report back in the comments with effective tweaks.

  3. Five gallon buckets with water can be deadly for toddlers. Precautions should be taken.

  4. I’ve read that I should change the water/hay monthly. What do you think? And if yes, if I pour out the water, will I be allowing some mosquito larvae to hatch? I’m going to try to pour it out near a drain, if possible.

    1. Hi, Sally. Different species of mosquitoes respond differently to the types, amounts, and ages of the biomass, so I just add a few bits of new plant material once a month (when I’m replacing the BTi dunk). I don’t dump my buckets: they are under trees and don’t get above 1/2 full, and the accumulating algae will attract mosquitoes ready to lay eggs. If you do pour the water out, any existing larvae will die when deprived of standing water (assuming the water is poured onto dry yard / lawn). Some eggs may also get poured out, but these won’t produce adults unless they land where there will be standing water for at least a week at a time. So, it’s fine to pour and restart monthly if this is the method that works for you and your area!

    1. If the bucket material allows, you can drill / poke small overflow holes about 3″ from the top, but I haven’t had an overflow problem because 1) the initial height of water in the bucket is only a few inches and 2) the buckets are positioned under shade trees. The shade keeps the water cool enough to attract pregnant mosquitoes. In my tests, buckets in direct sun here in Nashville get too hot — over 100 degrees. This temp will kill the larvae, which is our goal, but it can also convince a mosquito to go somewhere “safer” to lay eggs.

  5. Hello! My bucket of doom has been going for about a month. It is absolutely fascinating to see it in action. Eggs have hatched and there are little beings swimming in the water. I have half of a mosquito dunk in the bucket. To be certain I am doing this correctly, will there be some larvae alive in the water for a short time before they die? Or should the dunk kill the larvae upon hatching? I do not want my bucket of doom to be a mosquito factory.

    1. Hi, Holly, I’m glad to hear you are enjoying the experiment! Yes, the larvae do hatch, because BTi doesn’t affect the eggs. In my tests, the newly-hatched larvae only survive for a few hours (my average is about 3 hours). This means you could see live larvae / Wrigglers at any time. But because the dunk kills the larvae before they can advance to the next life-cycle stage, the bucket should never have pupae / Tumblers present. (The illustration in my post shows what the two stages look like, but I think the pupae look like little commas or shrimp.)

      1. Thank you for your response. I am happy to know that my bucket is working the correct way!

      2. This is fascinating! I’m thinking of trying SOON.

        I’m curious if the bucket of doom attracts more mosquitoes to an area than would otherwise occur (akin to Japanese beetle traps/)?

        I absolutely get swarmed (and bitten-), but they don’t itch me as much as they do for my kids.

        Also- do you have any genius black fly tricks?!

      3. Hi, Gillian, Yes, any stagnant water will attract mosquitoes, including the water in Buckets of Doom, so I’d advise placing the Buckets in areas that aren’t immediately adjacent to human sitting / living spots.
        I don’t have personal experience with Black Flies, which is a common name for many different species, but any Dipteran in the same suborder w/ mosquitoes will also be killed in their larval stage by BTi. You can google “Black flies” and “BTi” to read studies.

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