After months of unpredictable and extreme weather, experts are now warning that Britain’s recent hot and humid spell could fuel a mosquito boom.
Slapping away mozzies used to be one of the downsides of going on holiday to sunnier climes, but as seasons in Britain warm up, it’s a challenge we are increasingly facing here, too.
New research from Which? looked at how long insect repellents can keep the blood-sucking midges at bay, and found that expensive doesn’t always guarantee the best results.
In fact, they discovered that some of the priciest options stop working in under three minutes, but a cheap supermarket option that costs just £4 was effective for nearly 10 hours.
The consumer title tested 12 products, asking brave volunteers to stick their bare arm in a cage full of mosquitos to see how long it would take for them to be bitten,
Two products fared especially poorly in the tests and failed to protect the exposed limbs for more than a few minutes: Pestects Mosquito Repellent Bracelets and Meadows Organic Citronella Spray.
Both products are marketed as being suitable for sensitive skin and environmentally friendly alternatives to harsh chemicals.
Pestects’ brightly coloured mosquito-repellent bracelets promised up to 300 hours of protection per band, but in Which?’s laboratory tests, volunteers wearing them were bitten in less than three minutes. At £19.99 for 12 bands, they were also among the most expensive products tested.
A £4 insect repellent came out on top of Which?’s test (file photo)
Meadows Organic Citronella Spray, which costs £6 for 100ml, performed little better.
The spray relies on unrefined natural oils, including citronella, lemongrass and peppermint, but offered scant protection against mosquitoes, with volunteers bitten almost immediately.
However, Asda’s own-brand Extra Strength Insect Repellent spray provided complete protection for an impressive 9.5 hours.
At just £4 for a 125ml bottle, it matched the performance of brands costing more than twice as much.
Natalie Hitchins, Which? Head of Home Products and Services, said: ‘Whether you’re heading abroad or just enjoying your own garden this summer, avoiding nature’s most bloodthirsty critters shouldn’t break the bank.
‘Our tests reveal that some pricey, fashionable repellents can be a complete waste of money, offering less than three minutes of protection.
‘Crucially, you don’t need to pay a premium to stay safe – a £4 supermarket spray beats the flashy brands to deliver hours of reliable protection.’
Asda’s own brand spray performed well
Which? found several other products that kept volunteers bite-free for the full 9.5-hour test, although none were as cheap as Asda’s own-brand spray.
Shoppers looking for an effective repellent should check the ingredients list for proven active ingredients, including DEET, which works by confusing insects and driving them away.
DEET is widely regarded as the gold standard for repelling mosquitoes and ticks, although it does have drawbacks, including the potential to damage plastics and synthetic fabrics.
The DEET-based products tested by Which? – including Jungle Formula Maximum Aerosol Insect Repellent (£7.20), Boots Repel Maximum DEET & PMD Aerosol (£9.10), Pyramid Trek 50 (£9.50) and Lifesystems Expedition Max DEET Mosquito Repellent (£9) – were all found to be highly effective.
However, testers noted that some were less pleasant to apply, while others had off-putting odours.
Autan Insect Repellent (£5.65), which contains 20 per cent picaridin – a synthetic compound that helps stop insects from ‘smelling’ you – also delivered strong protection.
It kept mosquitoes completely at bay for the full nine and a half hours, without a single reported bite.
Incognito Insect Repellent Pump-Spray (£13.99) was more expensive, but also performed well. Instead of DEET, it uses plant-derived PMD, made from lemon eucalyptus tree extract, and protected volunteers for nine hours.
It is also suitable for babies from six months old.
For shoppers looking for a multitasking product, Which? found Boots Soltan Soothe & Moisturise Aftersun Lotion with Insect Repellent kept insects away for 4.5 hours – enough protection, potentially, for alfresco dining after a day in the sun.
All of the best-performing mosquito repellents in Which?’s test used proven active ingredients, rather than relying on vague ‘natural’ claims.
The hot and humid weather has been the perfect breeding conditions for mosquitos
The consumer group said four ingredients have good scientific evidence behind them when it comes to repelling mosquitoes: DEET, icaridin, PMD and IR3535. By contrast, the worst-performing products tended to rely on unrefined essential oils, such as citronella, lemongrass or peppermint, which may smell summery but offered little real protection in testing.
The gold standard, particularly for high-risk areas where mosquito-borne diseases such as malaria are a concern is DEET.
Icaridin, also known as picaridin, is considered a strong alternative. Recommended by the World Health Organization for protection against mosquito-borne diseases including Zika and malaria, it is effective, generally more pleasant on the skin and does not come with DEET’s reputation for melting plastics.
DEET formulas generally last 6 to 8 hours, while natural PMD and Icaridin formulas should be topped up every 4 to 6 hours or sooner if you’ve been swimming or sweating heavily.
PMD is the main ‘natural’ option with proper evidence behind it. It is derived from the lemon eucalyptus tree and can be highly effective when correctly formulated. But Which? warned shoppers not to confuse it with ordinary citronella oil or plain, unrefined eucalyptus oil, which are not the same thing and performed poorly.
IR3535 is another reliable synthetic repellent, although Which? says it is better suited to lower-risk, non-malaria regions rather than destinations where stronger protection is needed.
It’s also key to remember that mosquito repellent only works if it has been applied correctly. That means ensuring that wrists, ankles, necks, and hands are fully covered in the product – and only apply it after sunscreen.
Experts also urge people to spray the repellent into your hands first in a well-ventilated area, then rub it onto your face, remembering to wash your palms afterward.
