Updated: May 8
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 an ex 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 plastic bottle, such as a plastic milk bottle. Cut the bottle in two at around the point at which the shoulders meet the sides and the invert the top section, pushing it into the bottom section like a funnel (minus the lid, obviously).
You need to gauge where you cut the bottle so that the top section is not narrower in diameter than the base section as otherwise the top will fall into the bottom. With some styles of bottle I find that I need to use two bottles; putting the top section from one bottle into the bottom section of the other.
If you want to hang the trap up make two holes near the top of the sides of the base of the trap, opposite one another, and thread some string through the holes to form a handle. Hang the trap in the tree or shrub which is attracting the hornets.
Into the bottom of the decapitated milk bottle put about 2 inches of brown beer . Make sure that you have not filled the bottle up to such an extent that the hornet can reach the neck of the upturned top half and climb out. Brown beer used as a bait seems irresistible to hornets (and slugs), but doesn’t appear to interest honey bees at all.
Your hornet trap should look a bit like this
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 are standing it on something - otherwise add the string loop and hang it up.
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