Bulbs > Ian Young's Bulb Log - Feedback Forum
Bulb Log 2019
Ian Y:
Happy New Year everyone, I am back with another year of Bulb Logs and there is no shortage of work or flowers this week.
http://www.srgc.org.uk/logs/logdir/2019Jan021546428317BULB_LOG_0119.pdf
Steve Garvie:
Happy New Year Ian!
Another entertaining and informative read though I feel somewhat guilty that you are grafting in the garden while I sit in front of a warm fire supping Port. ;)
I’ve also had die back of a mature Sorbus which was followed by the “unexplained” death of a couple of mature Rhododendrons (augustinii and thomsoni). I fear that Honey Fungus was the culprit. The dead wood supported fungi not unlike the main image you posted though I could find no evidence of the characteristic “bootlace” rhizomorphs. Is it possible that a form of Honey Fungus could be causing the die back issues you have seen?
Ian Y:
Steve I am very interested to learn your experiences and do know the problem that honey fungus can cause and I did consider it as a possibility but I do not believe that to be the cause in our garden.
There appears to be a number of fungi that can have the common name honey fungus but what is growing on the stumps I show is not The Honey Fungus also all woody plants surrounding are in good health.
I will be keeping a very careful watch on the situation.
Alan_b:
I lost a mature sorbus unexpectedly a few years ago. The death was followed by a good crop of mushrooms around the base which certainly resemble the ones in your picture, Ian. But I am no expert on fungi so it might just be a superficial resemblance. My crop of mushrooms I took to be Honey Fungus, but I'm no expert, as I said. Here is a picture I posted at the time http://www.srgc.net/forum/index.php?topic=14346.msg366900#msg366900
Steve Garvie:
Hi Ian,
I gather there are a number of species of Honey Fungus (Armillaria) which vary in the appearance of their fruiting bodies and in their plant pathogenicity. All have white spores and this can often be seen as a powdery “icing-sugar” coating on the tops of the lowermost mushrooms (falling from the “gills” of those above). I gather that trees are mainly infected by the thick bootlace-like roving rhizomorphs which grow out through the soil from infected plants at a rate of about 1m per year. Spores very rarely cause infection in living plant tissue. The fungus attacks the host plant just below the soil surface invading roots and the root collar. Death occurs when the fungus fully girdles the host.
These fungi thrive on both living and dead wood but the rhizomorphs themselves are only viable when attached to the “main body” of the fungus deriving their nutrition from the decaying host tree. It follows that removing all dead wood and infected woody plants is beneficial as is deep cultivation of the soil (by cutting through the rhizomorphs and depriving them access to their food source). Butyl liners sunk into the soil can act as a physical barrier to spreading rhizomorphs.
There are a number of resources on the internet regarding Honey Fungus -most make grim reading. In reality spread of infection is usually haphazard, slow, creeping and unpredictable but generally without the domesday scenarios predicted in the literature/online. I would certainly remove as much of the infected plants and deadwood as possible -preferably burning it or disposing of it offsite. Digging deep trenches around nearby treasured woody plants might prevent spread of rhizomorphs (which can be incredibly difficult to find) and avoiding mulching with brushwood chippings is probably also sensible as is clearing soil away from around plant collars. Armillaria target woody plants including trees, shrubs and some woody perennials. The appearance and spread of infection is complex being linked to fungal pathogenicity and host susceptibility.
Of course all of this is unnecessary if you do not have Honey Fungus and I think your first step is to obtain a true “diagnosis”. Look for white sheets of fungal tissue between the wood and bark of the infected tree at and just below soil surface level -this has a mushroom-like smell. Check the colour of the spores and look for evidence of rhizomorphs in the ground radiating out from the infected Sorbus. If this is Honey Fungus then I fear you will have some hard graft ahead of you. Conventional wisdom is that there is no chemical treatment for Armillaria infection. In the old days a 1:20 solution of Armillatox poured around the woody base of mildly infected or at risk plants seems to have been effective. Sadly my supply has long gone and I don’t think it is available online these days.
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