I'll try and take pictures of this whole mess.
There's huge amounts of bees swarming both the top left in the standing tree trunk, and the section on bottom.
Afraid if I use a contact killer, they will swarm from the side I'm not spraying.
Got good advice from Greg W on this yesterday evening by phone. I'll order some Taurus insecticide... Then give them a couple of days to die off.
I bought some Taurus insecticide, for use around outbuildings and inside them. My main targets were ants outside, and brown recluse spiders inside. I've not seen any ants since, and have found some dead spiders. It seems to work. If I was wanting to kill them, I'd just mix half gas and half diesel and spray the snot out them. I used to do that on wasps and bumblebee nests in tobacco barns, and it will kill on contact.