Billions upon billions of microscopic worms, doing nature's work
Each summer, as windows open and fresh air enters, so too do the small, persistent creatures that share our world. Darragh Ennis — entomologist by training, quizmaster by trade — has turned years of academic study into a practical household remedy, reminding us that the natural world often holds the most elegant answers to the problems it creates. His recommendation of microscopic nematodes to combat fungus gnats is less a gardening tip than a quiet argument for working with nature rather than against it.
- Fungus gnats multiply rapidly in houseplant soil and resist most chemical treatments, leaving many plant owners feeling defeated before summer has properly begun.
- Darragh Ennis, known to TV audiences as The Chase's The Menace, used TikTok to share an entomologist's solution that most homeowners have never encountered.
- Nematodes — invisible parasitic worms that kill insect larvae from within — can be ordered online for around £12 and applied simply by mixing them into a watering can.
- Beyond nematodes, a toolkit of natural deterrents including basil, essential oil sprays, and apple cider vinegar traps offers layered, chemical-free defences.
- The approach signals a broader shift in how people might manage household pests — away from toxic treatments and toward solutions borrowed from the soil itself.
Darragh Ennis occupies an unusual space in public life — familiar to millions as a quizmaster on The Chase, yet trained as a scientist who has spent years studying insects. That combination proved useful when he turned to TikTok to address a problem many homeowners quietly dread: the arrival of fungus gnats.
These tiny black flies appear around houseplants each summer, drawn to the nutrients in potting soil and capable of multiplying faster than most people can manage. Chemical treatments exist but carry their own costs — toxicity, mess, and unreliable results. Many simply give up on their plants rather than fight a battle that feels unwinnable.
Ennis's solution comes from his PhD research: nematodes, microscopic worms present in soil across the entire planet, most of which go entirely unnoticed. One species in particular parasitises insect larvae, killing them from within. The method requires no chemicals — only a packet of Sciarid Fly Nematodes, available on Amazon for around £12, mixed into a watering can and poured over affected plants. The nematodes do the rest, dispersing through the soil and targeting larvae at their source.
For those wanting additional protection, Ennis's advice sits alongside other natural options: aromatic plants like basil, lavender, and marigolds that repel flies through scent; essential oil sprays blended with water and vodka; and homemade apple cider vinegar traps that catch fruit flies before they settle. None involve professional intervention or chemical exposure.
As summer opens windows and invites the season in, Ennis's recommendation quietly makes a larger point — that a £12 packet of invisible worms, rooted in genuine scientific understanding, may be more powerful than anything found on a hardware store shelf.
Darragh Ennis has a problem most people don't think about until summer arrives and the windows come open. As a quizmaster on The Chase, he spends his days blocking contestants from winning prize money. But when he's not on set, he's an entomologist—a scientist who studies insects—which means he knows exactly what's about to invade your home the moment you let in fresh air.
The culprits are fungus gnats, those tiny black flies that materialize around houseplants without warning. They're attracted to the nutrients in potting soil and can multiply faster than most people can tolerate. Chemical treatments exist, but they're messy, toxic, and often ineffective. Many plant owners simply give up, abandoning their green spaces rather than wage war against an invisible enemy. Ennis, who goes by The Menace on the quiz show, decided to share what he's learned through years of studying insects: there's a better way.
In a TikTok video, he introduced viewers to nematodes—microscopic worms so small they're invisible to the human eye, yet so abundant that billions upon billions of them exist in soil everywhere on Earth. Most people have never heard of them, and fewer still understand what they do. One particular species has a gruesome but effective talent: it crawls inside insect larvae and kills them from within. It's nature's own pest control, operating silently in the soil without chemicals, without toxins, without the collateral damage of conventional treatments.
The method is straightforward. You order nematodes online—Ennis found Sciarid Fly Nematodes on Amazon for around £12—and mix them into a watering can. Pour the solution onto your houseplants. The nematodes disperse through the soil, hunting down fungus gnat larvae and eliminating them at their source. Ennis studied these organisms for his PhD. Now they're solving a problem in his own home, a practical application of years of academic work.
For those hesitant about nematodes or wanting additional defenses, other natural remedies exist. Basil, lavender, mint, bay leaves, and marigolds all repel flies through scent alone. Essential oil sprays—mixing water, a few drops of peppermint or lemongrass oil, and vodka to help the oils blend—can be spritzed around windows and doors. A homemade trap combining apple cider vinegar and dish soap in a bowl, covered with cling film and punctured with small holes, catches fruit flies before they settle in. None of these require chemicals. None require professional pest control. They're all available to anyone willing to try them.
As summer approaches and more people open their windows to the season, the question of how to manage the insects that follow becomes urgent. Ennis's recommendation points toward a shift: away from chemical dependency and toward solutions that work with nature rather than against it. A £12 packet of microscopic worms might seem like an odd solution to a houseplant problem, but for anyone who's watched fungus gnats destroy a collection of plants, it's genius.
Citas Notables
They're really hard to get rid of, especially when they live in your houseplants. Getting rid of them with chemicals is really hard.— Darragh Ennis, on fungus gnats
I studied them for my PhD, and now they're useful in my house.— Darragh Ennis, on nematodes
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Why are fungus gnats so hard to kill with chemicals?
They live deep in the soil where sprays and treatments can't reach them effectively. They're also prolific—one plant can harbor thousands of larvae. Chemicals often kill the adults you can see but miss the ones developing in the compost.
And nematodes work because they're already part of the soil ecosystem?
Exactly. They're native to soil everywhere. You're not introducing something foreign—you're just adding more of what's already there, but in concentrated numbers. They do what they've always done: hunt larvae.
Is there a risk of using nematodes? Could they harm the plant itself?
No. They're parasites of insects, not plants. They won't touch your soil or roots. Once they've eliminated the gnat larvae, their population naturally declines because there's no more food.
Why isn't this more widely known?
Most people don't think about soil biology until there's a problem. Garden centers push chemical solutions because they're profitable and visible. Nematodes work quietly, underground, so they don't get the marketing push.
How long does it take to see results?
A few weeks typically. You won't see an immediate die-off like you might with a spray, but the infestation gradually collapses as the larvae are eliminated.
What's the appeal for someone like Ennis, an entomologist, recommending this?
He understands the biology. He's not selling a quick fix—he's offering a solution that actually addresses the root cause. For someone who studies insects professionally, it's the logical choice.