Lots of Mushrooms

Agree

That's a bit of a worry...   I'll let the people who look after the woodland know about it, and send them photos; thanks, Ashgale.

Yes Honey Fungus has got an undeserved reputation, the various forms recorded in the UK all seem to be native species and whereve possible should be seeking to live with it. There is quite a lot of alarmist information about Armillarias but their role in turning wood into material useable by other organisms is basic to many food webs and the pathogenisity of the various forms is quite variable. I'm not up to date with the latest species attributons, I believe the British specimens had been allocated to five different named groups, but a fairly simple three group division is good enough for the concerned gardener, based on rhizomorphs and pathogenicity. Forms that produce extensive rhizomorphs tend to be of limited lethality, those producing a limited network, particularly a limited soil network of rhizomrphs tend to be of only medium lethality and those which are the most lethal to a wide range of woody plants produce few rhizomorphs beyond the infected plant.

Some plants are more prone than others - Cherries seem especially susceptible and probably the main source of horticultural antipathy toward Honey Fungus. There are lists of plants that are supposedly resistant but there doesn't seem much solid evidence behind these lists, the most important protection is overall health of the plant. There is no chemical treatment against Honey Fungus although a cleaning fluid was repackaged and sold as such for years and some garden centres will still offer this even though it is now illegal to make any claim of effectiveness. In the Armillaria forms that do produce extensive rhizomrphs there is well established evidence of growth of up to 10 metres in optimal conditions, these being moist uncompacted soils. Lab based research has shown that rhizomorphs can grow up to 1 metre a year, however there is no evidence that anything like this is matched in the wild, although very extensive growth was known in coal mines - which is probably where the name bootlace fungus comes from, and another source of bad press, rot in pit props being a killer.

If there is concern about Honey Fungus the only effective treatment is removal of the food source - dead and dying plants or building waste with timber mixed in. The rhizomorphs will eventually die if cut off from food sources, although soils and composts with a high peat or woody fraction can sustain them, so digging out the rhizomrphs can also be helpful although it is usually a pretty grim task, thankfully they do only rarely reach down more than 40 centimeteres and have difficulty penentrating compacted and clay soils. It is also worth noting that to some extent the presence of fruiting bodies excludes the presence of rhizomorphs spreading out into the soil so early action can prevent soil rhizomorph development. One the important lessons about Armillaria solidipes the 'worlds largest living organism' is that it was only able to grow to this size by not killing its native hosts and was only recognised because it does readily kill some of the planted timber.