Gummosis on nectarine - whole of trunk

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MikeHardman

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Gummosis on nectarine - whole of trunk
« on: August 17, 2014, 12:17:54 PM »
My young nectarine flowered well this spring, but the fruits disappeared (I think rats stole them), and the flowering twigs have died off. More worryingly, the whole of the trunk is covered in gummosis eruptions (mainly on the shaded side).

Note:
- An adjacent clementine has a bad patch of gummosis
  (see http://www.mgsforum.org/smf/index.php?topic=1855.0)
- I have increased watering recently, but I don't know if the gummosis began beforehand.

I would appreciate any opinions on:
- identification
- treatment
- significance for adjacent Citrus, Prunus and olive trees

Regards,
Mike
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England

David Bracey

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Re: Gummosis on nectarine - whole of trunk
« Reply #1 on: August 18, 2014, 07:58:30 AM »
You have physiological disorders!  Gummosis is another.  It is the plants response to " damage" from, for example pruning, wind damage etc.  it seems to aggravated by pruning in wet weather.  Therefore prune when it is expected to be dry.  When do the locals prune?  There is no cure. 

Leave the watering well alone..I note that you are using stones which will only hold the heat?.perhaps mulching and creating a mat with straw, cuttings would be better.  Roots will spread out away from the trunk and close to the soil surface where the water is. 
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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Alisdair

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Re: Gummosis on nectarine - whole of trunk
« Reply #2 on: August 18, 2014, 11:10:12 AM »
Though David's suggested reaction to "damage" seems highly likely, the 2nd picture makes the exudations look as if they might possibly be a reaction to an adult woodboring beetle (perhaps Capnodis) feeding?
Alisdair Aird
Gardens in SE England (Sussex); also coastal Southern Greece, and (in a very small way) South West France; MGS member (and former president); vice chairman RHS Lily Group, past chairman Cyclamen Society

David Bracey

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Re: Gummosis on nectarine - whole of trunk
« Reply #3 on: August 18, 2014, 01:10:50 PM »
Mike I answered this question in August 2012?  Look under Information , "Ask the Expert" for some more info. 
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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MikeHardman

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Re: Gummosis on nectarine - whole of trunk
« Reply #4 on: August 18, 2014, 02:37:44 PM »
David:
Yes - thanks -  I see (http://www.mediterraneangardensociety.org/experts.html).
I wonder if it is getting too much water? It is difficult to tell due to my irrigation going down a 50mm pipe straight to the roots. If that was the case, I might have expected to see water expression from the leaves or oedema on the leaves. The leaves are perhaps smallish, but in themselves they look OK for colour, turgidity, lack of PLC, etc.
I am sure the gummosis is not due to physical damage, since the exudations are all over the trunk, and the bark itself looks perfect.
Pruning in dry weather: noted. It has not been pruned at all and we haven't had rain for months now.
Where I used stones, I have put sufficient that the lowest ones nearest the trunk are shaded themselves by other stones on top, the aim being to keep the inner stones cooler. I have more Aptenia to prune; I shall use that as a blanket instead.

An aside:
Mostly, I have used Aptenia as a non-rooted mulch - I just spread the blanket of prunings out and pile it up as needed to make it deep and dark enough. But even where I have used Aptenia as a *growing* mulch, around the base of a pomelo, I have had no problems. The pomelo is growing well and has some fine fruit swelling.

Alisdair:
Capnodis infestation - I hope not! But I'll look into that. Thanks.

I will remove some of the exudations, and see if they recur.
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England

David Bracey

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Re: Gummosis on nectarine - whole of trunk
« Reply #5 on: August 18, 2014, 05:11:12 PM »
Mike try to double the area of apteniaso that it matches the top growth.  Did the " dead " branches carry flowers?  If yes they probably died from blossom rot caused by monilia.  D
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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MikeHardman

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Re: Gummosis on nectarine - whole of trunk
« Reply #6 on: August 18, 2014, 09:21:28 PM »
That's interesting, David; thanks.

Having read http://en.wikipedia.org/wiki/Monilinia_fructicola,
 some of the symptoms fit (dead flowering twigs, gummosis), but I'm not sure overall, since:
- the flowers were fine, and were following by a high % of fruit setting
- the mainly weather was dry around the flowering time (and we have had only sporadic rain since)
- the fruit, though they disappeared when small (and pretty hard), were showing no signs of brown rot just beforehand (they disappeared overnight; no stones on the ground, nada)

I have seen no cankers on the trunk, even around the many eruptions of gum. Part of me wants to pare back some bark to see if there is any discolouration (or Alisdair's beetle borings); but part of me does not want to provide a point of enty for more pathogens.
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England