There is a chemical, Butyric anhydride, which is sold in America under the name Bee Go. They use it for clearing bees from supers so they can take the honey. It stinks and, personally, I wouldn’t let it within 100 yards of any honey I was going to take. I do have some, but have almost run out and I can’t get any more as they aren’t allowed to ship it by plane and they seem to have forgotten how to ship things by ship.
The purpose for which I use it is for steering ungetatable swarms to where they can be reached; for persuading scouts that a desirable cavity for a new home isn’t desirable after all; and for shifting colonies out of tight places, such as between the double skins of a shed wall or between the rafters of a flat roof. The technique is to put a few drops onto a bit of cotton wool or a sponge on the end of a stick and insert it in the appropriate place to herd the bees. It’s very effective.
On one occasion, at Langton Herring, I was called to deal with a suspected swarm in the wall of a house. Indeed there were bees flying from a hole at ladder-top height. After observing them for a while, I concluded that the swarm wasn’t in the building – yet! They were scout bees looking for a new home for a swarm. Bee Go on a bit of sponge rapidly made up their minds to try somewhere else.
The householder was feeding his kids pasta in the garden and remarked upon the similarity in aroma of the Bee Go and the grated Parmesan cheese he was sprinkling on the pasta. That gave me an idea that I tried yesterday.
I took a sample of grated Italian cheese of that type to the allotment shed and the transparent hive. After making my daily measurements of temperature and mite-fall and also taking a photo through their entrance (shown below) I placed a good sprinkling of the cheese in the cap of its container and inserted it on the varroa tray so that it sat directly under the cluster at a distance of less than 2 inches. I watched closely while slowly counting up to 100. There was no visible reaction from the bees. Oh tut! At least I tried. Here the photo through their entrance.