Asian Hornet: Why Trapping Queens Does More Harm Than Good

Introduction: the cut-in-half bottle, a national reflex

In just about every garden in France, between March and May, the same scene plays out: you cut a plastic water bottle in half, invert the neck, pour in a splash of brown ale, blackcurrant syrup and white wine, and hang the whole thing from an apple tree branch. The stated goal: to catch Asian hornet queens (Vespa velutina nigrithorax) before they build their nests.

The practice is widespread, encouraged by town councils, relayed by associations, shared thousands of times on social media. It is also, according to research by the Muséum national d'Histoire naturelle (MNHN) and INRAE, very largely ineffective — and ecologically costly.

We are in mid-September, that is, at the height of the period when nests reach their maximum size and colonies produce next year's queens. So this is the ideal moment to ask the question calmly, away from the springtime reflex: what should you actually do about the Asian hornet when you have a garden, an apiary, a terrace or a child playing outside? This article sorts out the useful measures, the neutral ones and those that make the problem worse.

The Asian hornet in France: where do things stand in 2026?

Accidentally introduced into the Lot-et-Garonne in the early 2000s, probably via a container of pottery shipped from China, Vespa velutina has colonised almost the entire French mainland in about twenty years. It is now present in the vast majority of départements, including at altitude and in the north-east, long regarded as buffer zones.

It is classified as an invasive alien species of Union concern (European Regulation 1143/2014) and, in France, as a category 2 health hazard for the honeybee since 2012. That last designation matters: it means the State recognises the threat to the beekeeping sector, but that it does not impose mandatory control measures nationwide. Management rests with the départements, the municipalities and local initiatives — hence the patchwork of practices.

What it does, and what it doesn't

A few useful pointers to clear up the most common confusions:

• It preys on honeybees, hovering in front of hives, but its diet also includes flies, wasps, spiders and ripe fruit.
• Its venom is no more dangerous than that of the European hornet or a wasp. The risk to life concerns allergic individuals and multiple stings, as the Vidal database points out.
• It does not attack a passer-by spontaneously. Aggression is defensive and is triggered near the nest, typically within a 5-metre radius, and more so if the nest is mechanically disturbed (hedge trimmer, mower, ladder).
• It cannot sting through thick clothing, but the length of its sting allows it to pierce thin fabric.

Key point: the Asian hornet is a major ecological and beekeeping problem, and an occasional health problem, confined to the area around nests. Confusing the two leads to inappropriate responses.

Why spring trapping doesn't work

This is the sticking point, because it clashes with a powerful intuition: "one queen caught = one nest fewer". The reasoning seems watertight. Yet the species' biology contradicts it.

Argument no. 1: the vast majority of queens never found anything

At the end of the season, an Asian hornet colony produces several hundred future queens. They overwinter, and only a tiny fraction — estimates published by the MNHN suggest less than 1% — manages to establish a viable colony in spring. The rest die of cold, starvation, parasites or predation, or are eliminated by competition between neighbouring queens.

In other words, natural mortality already does 99% of the work. Catching a few dozen queens in a garden amounts to drawing from the pool of those that were going to die anyway. Worse: by eliminating competing queens, you may reduce competition and improve the survival odds of those that remain. In the available studies, the net effect on the number of nests observed in the field is statistically undetectable.

Argument no. 2: beer traps mostly catch something else

This is the hidden cost. Monitoring protocols run by the MNHN and by several animal health protection groups have recorded what conventional bottle traps actually contained. The result is consistent: more than 95% of the insects caught are not Asian hornets.

You find, in no particular order:

The European hornet (Vespa crabro) deserves a special mention: it is much larger, far more placid, and beneficial — it eats flies and caterpillars and regulates other insects. Killing it by mistake is doubly counterproductive.

Argument no. 3: a badly placed trap attracts

A sweet, fermented bait hung near a terrace or a French window increases hymenopteran traffic in the area. Many households unwittingly create an attraction point three metres from the lunch table.

What really works: four measures in order of effectiveness

1. Locate nests and have them destroyed — the only action with a measurable effect

This is the action that counts. A mature secondary nest houses several thousand individuals and will produce hundreds of queens. Destroying it before the reproductives emerge, that is before the end of October, has a genuine effect on local pressure the following year.

September and October are, paradoxically, the best window for spotting nests: leaves start to fall, nests become visible, and colonies are still active.

How to spot a nest without going near it:

• watch the flight paths — hornets fly in a straight, repeated line between a food source and the nest;
• look up high, between 8 and 15 metres, in large trees, but also in dense hedges, under roofs, in sheds and compost bins;
• listen: a mature nest produces a continuous hum audible several metres away;
• equip yourself with a pair of compact binoculars rather than attempting a close-range visual inspection.

Once the nest is located: do nothing yourself. No insecticide spray (it won't reach 12 metres and it triggers an attack), no water jet, no fire, no shotgun — a practice as dangerous as it is ineffective, and a regular cause of accidents. Call the town hall, which will point you to the départemental scheme (some départements and municipalities subsidise all or part of the intervention), or contact a specialist company directly. Destruction usually costs between €80 and €200 depending on height and accessibility; our page on intervention rates sets out the 2026 price ranges.

2. Protect apiaries with mechanical devices

For beekeepers, the priority is not to kill hornets but to reduce predation pressure in front of the hives. Three approaches command consensus:

• hornet guards and grids fitted at the entrance, which let bees through but hamper the hornet's hovering flight;
• electric harps, effective but expensive and best reserved for heavily affected apiaries;
• repositioning the hives: clear the space in front of the landing boards, avoid damp valley bottoms and heavily wooded sites.

A selective hornet trap, fitted with calibrated entry cones and escape holes for small insects, can complement the setup in summer and autumn, at the apiary only, never at the bottom of the garden as a matter of course. The distinction is essential: trapping is worthwhile for local, targeted protection, not for population control of the species.

3. Remove sources of attraction around the house

In September, hornets are looking for sugars. Garden management makes a big difference:

• pick up fallen fruit under apple, plum and fig trees;
• cover open compost bins and outdoor kitchen waste bins;
• cover glasses and plates during meals outdoors — a mesh food cover solves the problem without any product;
• rinse cans and bottles before recycling;
• avoid sweet perfumes and loud floral-print clothing when gardening in late summer.

4. Make outdoor work safe

Most serious stings occur during an everyday activity: trimming a hedge, pruning, clearing a gutter, opening a roller shutter. Before any pruning work in September and October, inspect from a distance first for a minute or two. If you spot activity, abandon the job and call in a professional.

For anyone who works in hedges regularly, a beekeeping protective jacket is a sensible investment — it doesn't make you invulnerable, but it turns a potentially serious attack into a manageable incident.

Asian hornet sting: what to do

The recommendations from Ameli and Vidal are consistent and straightforward.

For a single sting in a non-allergic person:

1. Move away from the area quickly — the venom contains alarm pheromones that summon other hornets.
2. Remove rings and bracelets before swelling sets in.
3. Clean with soap and water, then disinfect.
4. Apply cold (a gel pack, never ice directly on the skin) for 15 to 20 minutes.
5. Monitor the area for 24 hours.

Call 15 or 112 immediately if:

• the sting is in the mouth, throat or near the eye;
• there are multiple stings (from around ten onwards, the venom load becomes toxic in itself);
• generalised hives, facial swelling, breathing difficulty, vomiting, faintness or a drop in blood pressure appear — signs of anaphylaxis, which can occur within minutes.

People already diagnosed with a hymenoptera allergy should keep their adrenaline auto-injector within reach throughout the season, and someone close to them should know how to use it. A properly stocked first aid kit, with dressings, antiseptic and an instant cold pack, has its place in every garden shed.

Worth knowing: a desensitisation treatment for hymenoptera venom exists and is covered by health insurance. It should be discussed with an allergist and is aimed primarily at beekeepers, professional gardeners and anyone who has already had a systemic reaction.

So what do we do next February?

If the urge to hang up a bottle returns in spring, three principles will keep you from doing harm:

1. Don't trap "blind" in a garden with no apiary and no known nest: the benefit-to-damage ratio is unfavourable.
2. If you do trap anyway, use only a selective trap with exit holes for small insects, and check it every two to three days to release non-target species alive.
3. Report any sighting on the dedicated citizen science platforms (the MNHN and INRAE run national monitoring schemes): data is worth more than a catch.

A field insect identification guide, even a basic one, prevents the most common mistake — confusing the European hornet, the Asian hornet, the German wasp and the hornet mimic hoverfly, a completely harmless fly that impersonates a hornet almost perfectly.

In summary

• Spring trapping of queens has never been shown to have any effect on the number of nests, and it kills beneficial insects on a massive scale.
• Destroying nests before the end of October is the only action with measurable impact; it is strictly a job for properly equipped professionals.
• September and October are the best time to spot nests: nests are visible, colonies are still active, and the reproductives have not yet dispersed.
• Around the house, the most effective lever remains removing sugar sources and taking care during pruning work.
• When it comes to stings, the rule fits in two lines: cold and monitoring for an isolated case, 15 or 112 for multiple stings, stings in the mouth or throat, and any systemic symptoms.

If you've spotted a nest or unusual activity around your home, describe the height and accessibility precisely before requesting an intervention: that determines the equipment needed, the lead time and the price. Our intervention services and our selection of protective equipment can help you prepare for next season without falling back on pointless reflexes.