Re: Fungus

John MacGregor wrote:
> on 12/16/03 6:19 PM, JanetTerVeen at terveen@comcast.net wrote:
>
>
>> My neighbor has a question for the group. Two years ago her
>> neighbor cut down a Calodendrum capense leaving the stump which is
>> now covered with flat topped light tan mushrooms. Above the ground
>> in various places along the root runs there are groups of white
>> round topped mushrooms. At a place where the round topped white
>> mushrooms are happy a Buff Beauty rose on it's own root was planted
>> 2 years ago so it's still pretty fragile. It has suddenly died.
>> Is it likely that the fungus caused the death of the rose? Both
>> neighbors are concerned as they both have other roses in this area.
>>
>
>
> Janet,
>
> Your neighbors have every right to be concerned. This sounds like a
> perfect example of Armillaria mellea (oak root fungus--in England
> they call it "honey fungus") taking advantage of the cellulose of the
> Calodendrum trunk and roots. Unfortunately, the mycelium also feeds
> on live wood, and rose roots are one of its favorite foods. If the
> roots of the now-defunct tree reach out into the area where the roses
> are growing, chances are good that the fungus will spread to them.
> Even if there is no actual contact between the tree roots and those
> of the roses, any one of the billions of spores that are being let
> loose by the mushrooms may lodge on or near the roses and send out
> mycelium that may not show up for a year or two, but eventually will
> cause the roses to sicken and die. As far as I know, there is no
> effective treatment for a an established infection of Armillaria. It
> might be useful to excavate and remove the remaining roots to dry up
> the fungus's food supply, but there can be no guarantee that the
> mycelium or spores will not remain in the soil.
>
> One encouraging note. Armillaria melea mushrooms are delicious. But
> you would be well advised to verify their identity before eating.

Janet
I must agree with John that the tan fungus on the stump is most likely Armillaria, but the round topped fungus caps growing along the roots sound like something different and could be one of the harmless saprophytic species which routinely take old roots to pieces.

One thing is certain I consider and that is the stump should be removed entirely as soon as possible with as much of the roots as can be managed. Otherwise it will continue to be a focus of infection for all the local area. Armillaria has a very effective mechanism for spreading itself in the form of strong black strands (commonly nicknamed "bootlaces") which travel through the soil to find an new food supply. What makes it doubly difficult to halt such a spread is that the fungus feeds indiscriminately on both dead and live wood and has been known to move through a neighbourhood by such intermediate stops as wooden fence posts. Needless to say the cleansing of the ground should include looking for the bootlaces and removing any that are found. The dead rose should also not be left in the ground but removed as soon a possible and disposed of. it may be possible to see if it is actually affected when it is dug up.

As John says there is little one can do in control other than to attempt to halt the spread by removing as soon as possible any neighbouring woody plant that begins to sicken and keeping an eye on any untreated wooden structure in the vicinity. There is however in NZ a new treatment which is claimed to be protective against Armillaria which can be applied to plants not yet affected and that is a culture of a beneficial fungus named Trichoderma, which is capable of inhabiting the area around the roots and like a good watchdog keeping off any other of its kind trying to invade its space. This fungus culture is available to us commercially in pelleted form under the name of Trichopel or as a powder for mixing with water as Trichoflow. Either treatment is simply applied to the roots of plants to be protected, preferably when they are first set out and to Trichiderma should stay in the root zone permanently keeping off many invaders.

In general it is usually unwise to leave a tree stump in the ground especially if the tree was diposed of because it was dying or even just sickly. So often if a pathogen is involved in its unthriftyness it has the mechanism to use the stump as a jumping-off place for further conquests.

Moira

--
Tony & Moira Ryan,
Wainuiomata, North Island, NZ. Pictures of our garden at:-
http://mywebpages.comcast.net/cherie1/Garden/TonyandMoira/index.htm

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