As the new bug correspondent for Good Housekeeping (not a title I chose, but one I’ve graciously accepted), it’s my unfortunate duty to report that there’s a new pest in town: thunderbugs.
While they sound like a finger-snapping gang from a 1950s musical, thunderbugs (also known as thunder flies or thrips) are actually some pretty sinister-looking critters. Imagine a microscopic flying scorpion (at least, that’s how they look to me). And this summer, they’re appearing in increasing numbers all across the UK.
So, are these oddly named, weirdly shaped bugs dangerous? And what should you do if a swarm heads your way? Well, I wouldn’t be a bug correspondent worth my salt if I didn’t have all the buzz-worthy info for you.
What are thunderbugs?
These mini-menaces are only about 1mm long, so you might not spot one on its own – but they travel in swarms, making their presence very known.
Like flying ants or ladybirds, thunderbugs are booming this year. ‘Like all insects, the development of thrips will be affected by temperature, and the extreme warm weather across the UK at the moment would be benefitting them,’ says Professor Helen Roy MBE, from the UK Centre for Ecology & Hydrology and the University of Exeter.
They tend to appear before it rains, so some people consider their sudden appearance as a sign that a storm is soon to hit – that’s how the as teeny-tiny weather forecasters got their name.
They’re also highly attracted to bright colours. That means blooming flowers and even your summery wardrobe can lure them in.
On the bright side, thunderbugs only live for about 45 days, so if you’re feeling swarmed, just know it won’t last forever.
Are they dangerous?
While they may be one ugly looking bug, they’re harmless to people and pets. At worst, they’re annoying – a buzzing, tickly nuisance. ‘They do not pose a risk to people,’ says Professor Roy, ‘but they can disfigure some ornamental and crop plants through their feeding behaviour.’
If you’re the proud parent of houseplants or a flourishing garden, though, it’s worth paying attention. Thunderbugs can wreak havoc by slicing open plant tissue to lay their eggs. The larvae feed on the plant for seven to 14 days, often killing it. Leaves and petals turn brown, and fruits or veggies can die off completely.
Still, they’re not entirely villainous. ‘Like all insects, they have important roles, for example being food for other species, such as predatory insects,’ says Professor Roy.
How to prevent and get rid of thunderbugs?
While the instinct may be to banish them immediately, Professor Roy encourages a more balanced approach. ‘Thrips are such beautiful insects with amazing life cycles, and I would encourage people, as much as possible, to tolerate their presence and accept them as part of our natural systems.’
That said, if your plants are suffering, there are a few simple, and cheap, ways to deter or prevent them.
Plant herbs
Like most insects, thunderbugs respond strongly to scent‑based disruption; that’s why citronella candles and pungent bug sprays are so effective. But for these thrips, there’s a much more natural approach that will actually give a sweet-smelling touch to your home or garden.
Planting fresh herbs like lavender, rosemary and thyme can be really effective at deterring thunderbugs. Plant them in a window box or in pots on your window sill to stop them entering your home. Or you can plant directly into your flower beds to protect nearby vegetation.
Put up a mesh screen
Another way to prevent the bugs from entering your home in the first place is to install mesh fly screens. They're super easy to put up and mean you can still enjoy summery fresh air, sans the pests. Options, like the EasyMax fly screen for under £20, make a cheap and cheerful addition to your home and are as easy as sticking a magnet to your window frame, plus they come off easily once the season is over.
Change your wardrobe
Thunderbugs love bright colours, so if you’re planning a BBQ and keep getting swarmed, maybe pick some neutrals from your wardrobe instead.
‘Light-coloured clothing and buildings can be attractive for many species of insects, including thunderbugs,’ says Professor Roy. ‘This could be due to surface temperature differences, as pale surfaces tend to be warmer.’ So really, they’re just looking for a warm cuddle – cute, sort of.
Make a DIY deterrent with lemon and cloves
Make your very own citronella candle equivalent using two items you may already have in your kitchen. Stud half a lemon with as many cloves as the flesh can take. Then simply take it to your outdoor BBQ or picnic and enjoy the buzz-free peace. Just make sure you’ve made your DIY bug bomb a good 20-30 minutes before you intend to use it so it has enough time to get pungent.
Add essential oils
In the same way that herbs can deter thunderbugs, strong scented oils can be used to the same effect. Simply soak a cotton pad in your chosen oil, like peppermint or rosemary. You could also sub in neem oil, which is a great pest remedy. Then place the soaked cotton pad in doorways or affected areas.
Alternatively, mix 5-10 drops of the oil with water and a splash of dish soap. Pour into a spray bottle and spritz your doors, windowsills and even directly onto your plants to deter the insects. Though I’d advise testing this remedy on a small section of your plant first, to make sure there are no bad reactions.
Water your plants
Not to shame you, but, if thunderbugs have shown a liking to your plants, it’s probably because you’re not watering them properly. The winged-bugs are attracted to dry plants, so a properly damp, well-watered plant is safer from an invasion.
Pin up sticky pads
If you have a really bad case of the bugs and a prize-winning patch you must protect, this is a great way to use thunderbugs’ affection for bright colours against them. The bright colours of the cards will lure them to landing, but the adhesive strip will prevent them from taking off again and heading for your plants. Use a clothes peg to pin these around your garden or stick them in the pot of your houseplants.
Thunderbugs may look like the stuff of tiny nightmares, but they’re harmless, unless you’re a plant. With a few simple tricks, you can keep your green friends safe while still appreciating (or at least tolerating) these bizarre little summer guests.
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