Honey fungus
How to recognise it
Clusters of honey-coloured toadstools at the base of an affected plant in autumn, white fungal sheets under the bark at soil level, and black 'bootlace' strands (rhizomorphs) in the soil nearby.
Life cycle and conditions
A soil-borne fungus spreading through root contact and rhizomorphs, often affecting stressed, damaged or old woody plants first.
Prevention
Keep woody plants healthy and unstressed; avoid planting known-susceptible species where an outbreak has previously occurred.
How to treat it
Remove and dispose of affected roots and stumps as thoroughly as possible, and avoid replanting susceptible species in the same spot — the only genuinely effective response.
No chemical cure is available for honey fungus — removal of affected material and careful replanting choices are the whole management approach.