The mosquito dunks that saved my plants (and my sanity) from fungus gnat hell are on sale for $17 this Prime Day
These mosquito dunks are fungus gnat kryptonite

Let me paint you a picture: It started innocently enough. A few tiny flies buzzing around my favorite monstera. "No big deal," I thought. "Just a couple of gnats."
The Summit Mosquito Dunks 6-pack is currently $17 at Amazon and while they're designed for mosquito control, they've become my secret weapon against the most annoying household pest known to plant parents.
For more Prime Day savings like this, head to our Prime Day deals live blog, where we're tracking the best offers as they land.
These aren't just for mosquitoes — they're fungus gnat destroyers. Drop one in your watering can, let it brew for 24 hours, then water normally. The BTI bacteria kills larvae in soil while staying completely safe for humans and pets. One dunk lasts 30 days.
Fungus gnats are the worst kind of house guests — they multiply without permission and refuse to leave. What started out as a couple gnats flitting around turned into a full-scale invasion within two weeks.
My apartment looked like a horror movie. Clouds of fungus gnats swarmed every time I walked past my plant shelf. They dive-bombed my morning coffee, invaded my laptop screen during meetings, and somehow managed to find their way into my wine glass during dinner.
Then I discovered mosquito dunks. Yes, mosquito dunks. I know it sounds weird, but hear me out. These little donut-shaped tablets contain a bacteria called Bacillus thuringiensis israelensis (BTI) that's basically kryptonite for fungus gnat larvae.
You drop one in your watering can, let it "brew" for 24 hours like the world's most boring tea, then water your plants normally. The BTI bacteria gets into the soil and absolutely destroys the larvae before they can become those annoying flying demons.
It's completely safe for humans, pets, and beneficial insects. It's just nature doing what nature does — one microorganism taking out another.
Within a week of using my mosquito dunk tea, the gnat population plummeted. Within two weeks, they were gone. Completely gone. I could finally drink my coffee in peace and chill on the sofa without swatting at my face like a maniac.
As my colleague Nikita can attest, the results are genuinely shocking — she was horrified by how many adult gnats were stuck to her yellow traps just one morning after putting them up. The combination of mosquito dunk tea and sticky traps cleared her monstera's infestation completely, and the plant even sprouted new growth within a week.
These bright yellow sticky traps work like fungus gnat magnets. The adults can't resist flying straight into them and getting permanently stuck. They pair perfectly with mosquito dunks since the dunks kill larvae in the soil while these traps catch any stragglers still flying around.
And here's the bonus: If you're dealing with actual mosquitoes, you can use these dunks exactly as intended. It's like buying a two-for-one pest control system. Each dunk lasts about 30 days and will keep you gnat-free for months.
At $17 for a 20-pack, these mosquito dunks are the best money I've ever spent on plant care. Trust me, if you're battling fungus gnats, skip the Pinterest remedies and go straight to the nuclear option. Your plants (and your sanity) will thank you.
There are plenty more deals to be had this Prime Day — make sure you check out our Prime Day live blog to make sure you're staying on top of all the latest sales and offers.
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Kaycee is Tom's Guide's How-To Editor, known for tutorials that skip the fluff and get straight to what works. She writes across AI, homes, phones, and everything in between — because life doesn't stick to categories and neither should good advice. With years of experience in tech and content creation, she's built her reputation on turning complicated subjects into straightforward solutions. Kaycee is also an award-winning poet and co-editor at Fox and Star Books. Her debut collection is published by Bloodaxe, with a second book in the works.
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