Dibotryon morbosum (Black Knot) on European plum trees

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Agi Adams
Posts: 1
Joined: 02 Sep 2014, 21:57

Dibotryon morbosum (Black Knot) on European plum trees

Post by Agi Adams »

Hello all,

I am new to this board today, so let me preface by saying I am not an experienced gardener but I do care for my charges. I am also a self-taught homeopath for over 21 years now.

We planted these two black plum trees here in Northern Vermont about 10 years ago. They were small and sparse and wispy when we got them and it took them at least 4 years to flower and fruit. That was in 2008. I know because I took pictures of the first plums. They were well-formed and very nice. Not a lot of them, but enough to be delighted by.

Due to late frosts and/or high winds, we had intermittent crops in the following years. Some scarce, one bountiful, others non-existent. Last year was the bountiful year. Huge amounts of plums (relatively, anyway)on both trees. Very nice. Very tasty. Then, after the harvest was over, I noticed the black fungus on a couple of the high branches in one of the trees. I couldn't reach them and made the mistake of putting off doing anything about them. I did prune the trees for the first time though, to allow them to "breathe" better. These trees stand side by side, about 20 feet apart, right outside our South-facing windows. Some of their branches touch a bit. Not much, but they do. This year, the fungus is on many of their branches, both of them. They are still putting out leaves and, other than the deformity of the fungus, they look healthy. No fruit this year. They did flower, but a windstorm got them before the bees did. However the flowers did not seem as vivacious either, as in other years.

I started feeding these trees some composted horse and goat manure in just the last 3 years or so. Before that, they just grew on their own mostly. The compost is from manure and organic hay that is fed to our two pet horses and two pet goats. They, in turn are fed organic hay and organic grain.

Does anybody have any ideas on how to approach this?

Thanking you all in advance,

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Re: Dibotryon morbosum (Black Knot) on European plum trees

Post by Mark »

Hi Agi

Do you know if there are similar trees in the area and how they are faring? If they are like yours it would suggest a problem due to the seasons locally. If they are doing OK it would suggest it is something you have been doing and, from what you have written, the likely suspects would be the compost or the pruning. So one could continue to observe the tree and see if it recovers on its own from, for example, the pruning.

Black knot is not yet in the materia medica so I tried fungus in the search page (http://www.considera.org/hrxmatmed.html?page=search).

This brings up:
Am-c. Ammonium Carbonicum
Lap-a. Lapis Albus
Thuj. Thuja Occidentalis
BD508 508
BD501 501
GW - T Transplant
GW - 508 Equisetum 508
Ferr-p. Ferrum Phosphoricum
Nit-ac. Nitricum Acidum
Sulph. Sulphur
Acon. Aconitum Napellus
Bell. Belladonna
Kali-c. Kali Carbonicum
Carb-v. Carbo Vegetabilis
Cupr. Cuprum Metallicum
Lyc. Lycopodium Clavatum
Sil. Silicea
Sol-v. Solidago Virg. aur.

Maute says of the last remedy: "Sensitive to cold. Can be caused by too much fertiliser" but you might want to go through all the remedies in the list to see if any of them are particularly close to what you have in Vermont.

Please let us know if anything improves.
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