Not much you can do. Dig deep trenches between infected tree roots and other trees you want to protect. Chemical treatment is available commercially (only from a licensed user, cannot be used by Joe Public), but is of dubious efficacy, and very expensive.

Resin

(1) Panic.

(2) Once you've done that, try physical barriers, buried in the soil. When digging, you should be able to find the "bootlaces" by which the fungus spreads, and destroy them. Remember to sterilise your tools (and boots) after use.

Honey Fungus isnt something you want in a garden as it can devastate certain shrubs and trees.
Control has been made far harder since greater European controls on pesticides came into place.
The previous standard control I have used is a product called Armillatox made by a British company. Since greater regulation this product can no longer technically be used for honey fungus control which is strange as the products name is partly linked to honey fungus- Armillaria. The product is now only licensed for use such as patio cleaning however their website which I just checked states the formulation remains unchanged so make of that what you will.

Hi,

Just caught up with this thread! I remember reading a couple of years ago of a man who went to a mushroom farm and got some well diseased mushroom compost. He dug it in and found that it did help with honey fungus.

His idea was that an organism which attacked one type of fungi would also attack another. He reckoned he was right.

I also later saw a tv program about fungi and the expert there did say that the reason that honey fungus hadn't killed off every tree in Britain was the action of other fungi.

A mushroom farm would probably give you their diseased stuff for nowt.

I think you could try it without harm.