Moth infestation ruined your wardrobe? You need this tiny wasp

Telegraph

5 hours ago

Overzealous hot-washers aside, there is no greater nemesis for the cashmere lover than Tineola bisselliella – the common clothes moth. We are now in the very worst of fashion seasons, that of these nasty sand-coloured little beasts, when they emerge in all their evil winged glory, the damage to our jumpers long since perpetrated by their larvae.
I have mourned countless precious items lost to moth procreation. A 1980s YSL blazer, Burberry scarves, assorted designer knits, a vintage rabbit fur coat (possibly for the best, but the mess was revolting), my childhood teddy, as well as my daughter's fancy navy- blue wool princess coat from when she was a toddler (sob), and latterly her favourite Anya Hindmarch Uniqlo jumper.
I am admittedly lax in my efforts at prevention. I have barely any proper storage, so my clothes are stuffed into drawers and the back of rails. I fear washing expensive knits, one because I don't want to ruin them, and two because over- washing destroys fibres and jacks up my water bills. In my 20s, my freezer was solely stocked with ice, vodka and jumpers, but now I have a child and a dog so it's jammed with fish fingers, peas and raw pet food. It seems I have unwittingly sacrificed my knitwear for the temperamental digestion of a small French bulldog.
I'm not alone. There are endless Reddit threads describing moth-related trauma, dread, the logistics of washing every item in your house – and even the suggestion of sprinkling diatomaceous earth under your furniture to dehydrate moth invaders. Former Vogue editor Alexandra Shulman only solved her extensive moth infestation by fumigating and industrially cleaning her entire house. The stylist and vintage aficionado Bay Garnett has lost cashmere Louis Vuitton, Chanel throws and four-ply cashmere sweaters. 'Four years ago I had people in to kill them,' she laments over the phone. She is now hyper vigilant, keeping her most precious knits in the freezer, where low temperatures will kill off larvae hidden in fibres. ('My husband and I have a silent war over who's going to get that corner of the freezer.')
Susie Lau, the fashion writer and influencer, has more tales of woe – 'Oh God, there's one flying around by the radiator right now,' she says, horrified. A treasured Prada jacket with a wool collar is double plastic-bagged. A ravaged £700 Celine top languishes in the back of a drawer 'mocking me'.
Meanwhile Kerry Taylor, who runs the notable vintage fashion auction house, relies on pheromone traps 'which tell you if there is moth activity' and a chest freezer for new pieces coming in. 'It's got to be -18C or more. That's the only thing I've found that works. All those sandalwood balls and lavender pouches? Forget it, they're not going to do anything.'
However, haute natural-fibre lovers may find salvation in the unlikeliest of bedfellows: microscopic wasps. Officially known as Trichogramma evanescens, the insects – less than 0.5mm in size – have been deployed as a revolutionary new biological treatment now being rolled out nationwide in the UK by Rentokil.
The Telegraph has in the past sent me to report from lots of glamorous places. When I worked on the fashion desk, my life was a flurry of fashion shows in Milan, New York, Paris. Pulling up to Rentokil's HQ in an industrial estate just off the M23 near Crawley, I did wonder if this was some kind of punishment. However, prepare to be as riveted (and revolted, as I was).
The wall inside the entrance is decorated with 12 framed uniform shirts, like a premiership footballer's trophy room. The different designs denote the companies acquired and held under the international Rentokil umbrella: yellow for California's Western Exterminator Company; grey and red for its Specialist Hygiene division; cornflower blue for Ehrlich, the US pest control company, which it acquired in 2006.
Upstairs there are training rooms for all these disciplines, with scenarios set up like a children's interactive role-play centre – in hell. An industrial kitchen features rodent droppings; a grain store, a rotten mouse; a loft has chewed wires and a wasp's nest; cockroaches are glued to the bottom of a supermarket hot food counter.
The hotel room scenario conceals moth damage in the wardrobe; the walls, carpet and bedding are splattered generously with theatrical blood, to train technicians for murder and suicide clean-ups.
This year marks the company's 100th anniversary. It is now the world's largest pest control company: it sits on the FTSE 100 and had a revenue of £5.6 billion in 2024. It operates in more than 90 countries worldwide, employs around 60,000 people and was recognised as one of Britain's most admired companies in a 2024 study.
The business was founded by Professor Harold Maxwell-Lefroy, an entomologist who conquered wood-boring beetles in the timber roof of Westminster Hall in the Houses of Parliament with his new chemical concoctions. In a plot twist worthy of Agatha Christie, Maxwell-Lefroy died that same year (1925) after accidentally inhaling insecticide fumes in his lab at Imperial College. His assistant, Bessie Eades, bought the rights to the company from his widow, launching the brand as a domestic service in 1928.
Last year, Nelson Peltz, the American billionaire investor (and Brooklyn Beckham's father-in-law), bought a 2.26 per cent stake via his Trian Fund Management. (His investment came after he sold his shares in the Walt Disney Company after a failure to secure board seats. Seemingly, having been rejected by the world's most famous mouse, he's now seeking to cash in exterminating Mickey's namesake rodents.)
Although, technically, rats are Rentokil's most profitable pest, accounting for 44 per cent of call-outs last year. Clothes moths make up just 1.05 per cent of visits, but while small in the pest-firmament, they are incredibly pervasive and destructive. The problem is that even once fully eradicated, moths can easily return, via new clothing, toys, furniture and fabrics being brought into the house.
Downstairs at Rentokil HQ there is a lab, staffed by three entomologists who investigate controls for all global pests except North America (Rentokil Dallas has its own testing centre). Here you'll find jars of moths and larvae, kept in culture to be used when required for experimentation. A plastic box contains a mound of knitwear, donated by colleagues. It was put in fresh and clean in 2017, on top of a square of carpet, then moths and carpet beetles (a similar scourge to clothes moths) were added. They have eaten fully through one jumper, the rest is covered in detritus. It is a fashion horror scene. Taped on the lab's wall is a list of recipes. House flies are fed a mixture of wheat bran and yeast powder; moths get fishmeal and yeast powder.
Rentokil is currently assisting Olivia Augusta, a Central Saint Martins final year jewellery design student, who asked for their help with her graduation project. She has duct-taped a sweater leaving sections exposed which was placed into a box with moths – when ready she will use jewellery to cover the holes left by the moths.
'You can spend an awful lot of money removing moths,' says Paul Blackhurst, head of Rentokil's technical academy. Indeed, earlier this year a £32.5 million mansion in west London had an infestation of moths so bad that its exasperated owners sued the vendor and were allowed to hand it back with an almost full refund.
'About 10 years ago there was a big rush for more natural home insulation using untreated wool,' Blackhurst says, shaking his head. 'Before it used to be washed in borax [sodium tetraborate, which works as an insecticide]. The problem is [moths] could be in anything, cavity walls, old furniture. You've got to find that pocket and isolate it.'
Moths adore our centrally heated cosy homes. They go for the good stuff, natural fibres – merino wool, cashmere, silk. ' National Trust properties with tapestries, butterfly collections, taxidermy, dead cluster flies around the base of windows –they'll thrive on that,' adds Blackhurst. Abandoned bird's nests hidden in chimneys are often an origin source. 'There's so many associated secondary infestations with bird's nests, it's phenomenal,' he says, smiling. 'Bed mites, bird mites, as soon as that material [the feathers] is exhausted they'll move on to the next thing [your clothes],' he adds. A dead rodent under a floorboard will have a similar effect. Once the moths have fed off the mouse, they will head to your cupboards.
This activity is incessant, which is why everyone I've mentioned this article to is so excited by the tiny-wasp army treatment, potentially offering a silver bullet to infestations. The real culprits are the moth larvae. Once impregnated into your fibres, they feed off the protein left there from your sweat or spilled dinner, and as they hatch and grow they decimate the fibres. When you've got adult moths flapping around it's too late.
Which is where the wasps come into play. Rentokil's Entosite treatment utilises microscopic Trichogramma evanescens wasps, which are released in small sachets at the site of infestation. They work as egg parasites: the wasps seek out moth eggs, then lay their own eggs inside the larvae – so instead of another moth, a new Trichogramma develops and hatches.
The treatment was first trialled in 2021 by conservators at Blickling Hall, a Jacobean National Trust stately home in Norfolk, in the face of a post-Covid moth explosion. These microscopic parasitoid wasps were used during a trial alongside pheromone traps (which attract male moths, reducing the chances of them finding a female). A year later, they saw an incredible 83 per cent reduction in moth numbers.
'The concept of biological controls has been around for years,' explains Blackhurst. 'As controls on insecticides tighten, and they get taken off the market, we're looking more into it.'
Traditional moth-busting involves heating a propert to 56C (not possible in historic houses where the heat can damage delicate textiles) or fogging with chemicals over a four-hour period (or a combination of both). A thorough investigation to locate the primary source means looking in the loft, up chimneys and under floorboards to find that errant rotting rodent or bird's nest. It is incredibly invasive.
'We buy the wasps and get them fresh,' Blackhurst says. They are sent out in timed batches, which will hatch over three weeks. The sachets have a tiny hole through which they will emerge, unseen. 'Their sole responsibility is to mate and find eggs, deposit their egg in the moth egg, which will then hatch and consume the moth egg. That's their protein source.'
Because moth life cycles will be at different stages, Rentokil will return and place more releases over a three- to six-month period, sometimes in conjunction with an insecticide treatment (especially for extensive infestations) that can be utilised after the wasps have finished, to zap anything remaining. 'It's a more natural, tailored approach for a longer-term strategy' he adds. Blackhurst is a man of cautious optimism. 'We've had good results,' he says, adding that 'we trial everything; we will not release something if we're not comfortable with it.' The treatment starts from £450, with an initial £100 survey cost taken off from the overall treatment cost.
'Human messiness is basically the cause of all pests,' Matt Green, Rentokil's principal entomologist tells me, popping a white lab coat over his Carhartt sweatshirt. The boardroom we are standing in is decorated with totems of Rentokil's century of extermination – the company marked its centenary earlier this year with a 'Pestival' ice cream van that handed out free treats in South London, albeit topped with chocolate covered mealworms. Rat taxidermy features heavily in the office decor, alongside framed Manchurian scorpions from China, emerald beetles from Japan, giant water bugs from Mexico. A trophy cabinet houses a royal ratcatcher sash from George IV's reign, vintage poison bottles, a branded Matchbox toy van among other archive ephemera. There are reassuring amounts of hand sanitiser and wipes scattered around.
Pests are, of course, relative. 'It's a hugely cultural thing,' Green continues, 'In Iran no one lifts the phone for pest control unless something is going to kill you. [Then there's] nuisance pests of the bourgeoisie – in America we have technicians that deal with millipedes. They're not going to hurt anyone, somebody just doesn't want them in their house because they're an icky bug. Pest control in the Middle East and Africa will treat snake infestations.' He compares it to Maslow's hierarchy of needs 'for pests'.
Green is based in the lab, where extermination and control products are tested and new treatments developed. In an ante room, decorated with enlarged close-up photographs of bugs, sits a line of prototype plastic fly-traps. The final product is in a rich puce hue. 'Thanks to PhD students from the University of Thessaloniki in Greece, who painted fly-traps in different colours as a test,' explains Green. Pink was the most effective shade for attracting them.
Along the corridor, sweltering behind thick plastic strips, lie several small rooms full of creepy experiments. There are boxes of mosquitoes and bed bugs, fed by donated but unusable NHS blood, deliveries of which come weekly. There are rolling cultures of flies, 100 of which get put into different ultraviolet fly-traps for testing every morning. 'We get through about 600 flies a week,' says Green.
Boxes of giant stick insects and Madagascan cockroaches (the largest will fill your palm) are kept as teaching tools to show what these beasts look like up close. 'You can get a biology degree in the UK without looking at an insect,' Green shakes his head, adding, 'when the population gets too big, sometimes the technicians take them home to keep as pets.' I watch as Fabio Leonel, his entomologist colleague, gently strokes a cockroach until it makes a hissing rattle noise.
They share jovial tales from the field. Blackhurst grins: 'There was an interesting rat problem which was linked to drains, but then a secondary infestation of fleas from the rats…'
My skin begins to itch. On the way home I turn up the air conditioning in the car to full freeze. I get home shivering. In my daughter's room I spot two moths flying above the carpet. I vacuum ferociously and spend the next three days washing every single item of knitwear in the house, saying out loud to any pupae within earshot, 'Beware. I will unleash the wasps.'