Updated: Nov 7, 2021
As soon as the weather begins to warm up in the spring queen hornets, who have kept a low profile all winter, start to appear. They are taking advantage of the warmer days to feed and look for a suitable site to create a nest in for the coming year. As a bee keeper this is an important time of year for me because a queen hornet trapped and killed now eradicates an entire colony later in the year. And if that queen happens to be an asiatic hornet then she is not an indigenous insect, but is one which is seriously upsetting our local eco-system, following the asiatic hornet's arrival in France in 2004.
So - how do you (safely) trap a hornet. You can buy traps which are commercially made, or you can make them yourself from a couple of plastic bottles. There are lots of recipes for the bait which you put inside the traps; here are a few ideas on construction and priming of a trap.
Monsieur Maillot, a professional apiculturist who used to sell his honey in our local market gave me instructions as to how to make an ecologically friendly trap. His trap is made from a plastic bottle with the top third cut off. This is inverted and pushed back into the base to form a funnel. He was very specific about dimensions. The hole at the bottom of the funnel had to be at least 7 millimetres in diameter, but no more than 8 millimetres wide. This makes it large enough to admit an Asiatic hornet, but too small to admit (and kill) the indigenous French hornet. At the side, above the level of any liquid, you need to to make a hole 5 millimetres in diameter. This would be big enough to allow a wasp to escape, but too small for the Asiatic hornet to get out of. Thus you are selectively trapping the invader without affecting the indigenous insect population.
The base of the bottle is filled with about 2 inches of sweet alcoholic ‘bait’. In recent years shandy – a mixture of beer and lemonade – has been the bait of choice although white wine and pomegranate syrup can be used if your hornets are particularly sophisticated. My bee keeping companion, Monique, and I found this most amusing as these ingredients make a very popular French aperitif – a ‘kir’. We would be, in effect, inviting the invaders round for ‘aperos’! My own recipe is brown beer (I am a northern lass) combined with the remains of a bottle of sweet white pudding wine, should you have some handy. This seems irresistible to hornets and slugs, but doesn’t interest honey bees at all.
I find it helps to put some small stones (submerged by the liquid) in the bottom of the plastic bottle to help stop it blowing over.
If you keep bees, you need to place at least one trap by every hive, close to the entrance; and they have to be checked regularly. If you don't have bee hives, put your traps in a warm spot or - if you have seen any hornet activity in your garden - put them there. Continue using the traps all year round. One fecund queen hornet caught on a warm winter’s day means one less hornet’s nest in the spring, but at any time of year a reduction in the numbers of aggressive asiatic hornets is welcome.
Here is a photograph of an indigenous hornet (on the left) an asiatic hornet (in the middle) and a honey bee on the right. Just so you know what you are dealing with