Acer ’Shaina’ stem cross-section black streaks

Discussion in 'Maples' started by James H, Feb 19, 2019.

  1. James H

    James H New Member

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    I have a problem with one of my Acers (a Shaina) and wanted to see if anyone could help identify what has gone wrong.

    It is fairly young, it was in the ground after I planted it last October after leaf drop and it looked very healthy. I took my eye off it a bit but watered it, it was in a sheltered, shady spot that isn’t very dry, around other trees - but last week I noticed dead portions on the branches and dead/burnt out buds on those branches. I cut back those branches but see here, at the point of the cut there’s a black stuff inside the stem cross section right down low.

    Any ideas?

    upload_2019-2-19_22-4-14.jpeg

    upload_2019-2-19_22-4-57.jpeg
     
  2. 0soyoung

    0soyoung Member

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    First, I hope you sanitized your pruner right after you did this.

    Second, do I understand correctly that the heavy stem you cut this from (on the right side in your pix) is outwardly okay?

    Anything that invades the xylem will be spread/propagated upward because this is the direction that sap flows in the wood. This means that this stuff originated below this point (in your pix where you pruned). Is there any scarring or other remnant bark damage below this?
     
  3. JT1

    JT1 Contributor

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  4. James H

    James H New Member

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    Yes, @0soyoung the pruners were disinfected,

    The black stuff was on the cut and that joined to the main branch. No damage below that.

    Apparently it’s “botrytis” and Shaina isn’t a great / strong variety and is susceptible to cold damage.
     
  5. James H

    James H New Member

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    @JT1 i should have posted back but I had it checked out an apparently it’s “botrytis” ... Shaina is particularly susceptible so it transpires. The roots looked healthy and strong when I repotted.
     
  6. JT1

    JT1 Contributor

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    @James H By checked out, you are saying it came back as positive for botrytis from a lab?

    My Shaina survived -25F for over 72 hours and over 10 days at -0F. But mine was established and over 20 years old when it saw those temperatures. They do need perfect drainage and will not tolerate saturated soil in late winter and early spring. Mine is planted in a bed that is mounded up.

    My educated guess (verticillium wilt) was based on the black ring present in the cross section cut in the photos. Most of the time it goes unnoticed this time of year unless you cut a cross section, as most don't notice until the heat of late Spring or early summer causes wilt because the black tissue limits moisture to the leaves.

    But nothing beats a lab diagnosis. Sometimes botrytis and verticillium wilt can both be present in the same tree when tested. Not trying to say my guess is right, I'm just saying a tree weakened by one can open up the door to several opportunistic pathogens. Most like the cold damp conditions that are persistent this time of year.
     
    Last edited: Feb 26, 2019
  7. Margot

    Margot Well-Known Member

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    I'm interested how you determined that there was no 'black stuff' below the cut you show in your photo. Did you make another cut further down?
     
  8. James H

    James H New Member

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    @Margot that was in response to @0soyoung who asked about scarring and bark damage below that point. I did not cut below the cut in the picture so do not know how far down that black goes but you can see from my photo that it is there at that very low cut point.

    No further dieback has occurred since I repotted and put in full sun. Before that, whole branches had large dead sections. But it has only been a week since I did that.
     
    Last edited: Feb 26, 2019
  9. James H

    James H New Member

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    @JT1 so it wasnt a lab diagnosis, I asked the author of a well known Japanese Maple book from here in the U.K. to have a look. So not scientific or conclusive but he has many years experience and stopped growing and selling this variety a few years back.
     
  10. emery

    emery Contributor Maple Society 10 Years

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    I thought botrytis was gray mold. Although of course it is a major issue for seedlings damping off. I've never heard anyone talk about it leaving a clogged vascular system like verticillium or for that matter fusarium. I assume @James H that your author is N.K.?

    Because this happened during the winter I would assume fusarium and treat with Alliete.

    @JT1 no lab services readily available on this side of the pond! What a shame it is.

    -E
     
  11. James H

    James H New Member

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    Correct @emery it was NK.

    I can look into Alliete.
     
  12. JT1

    JT1 Contributor

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    I think UK can send to RHS
    RHS Gardening Advice - How to send plant samples / RHS Gardening
    FERA does testing but I think it's 125.00 not exactly cost effective, but again I think it's for the UK.

    MA's got me watching Gardeners World to get through the Winter and dreaming of Spring. They were talking about testing for box blight and sending it to the lab.
     
    Last edited: Feb 26, 2019
  13. Gomero

    Gomero Well-Known Member Maple Society 10 Years

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  14. JT1

    JT1 Contributor

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    I only know of:
    A severe dieback of box elder (Acer negundo) caused by Fusarium solani(Mart.) Sacc. in Turkey
    A severe dieback of box elder ( Acer negundo) caused by Fusarium solani (Mart.) Sacc. in Turkey

    Fasarium caused by ambrosia beetle (insect vectored disease):
    https://www.google.com/url?sa=t&sou...FjABegQIBhAB&usg=AOvVaw2yiAQdGqxAUQnQTtGDxuQm

    In depth presentation on fasarium caused by beetle and transfered into seedlings in CA:
    https://www.google.com/url?sa=t&sou...FjACegQIAxAB&usg=AOvVaw3IfxGgPqEJrOBeizOBDRlG


    I have no experience with fasarium in Acer palmatum in my area.
     
    Last edited: Mar 6, 2019
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  15. James H

    James H New Member

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    I was told it was botrytis ... is this not the case do folk think?
     
  16. 0soyoung

    0soyoung Member

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    The papers on Fusarium that @JT1 provided are quite interesting. It is consistently noted, however, that infection requires an opening thru the bark to the wood, be it damage (as with verticillium) or holes bored by beetles/larva.
     
  17. JT1

    JT1 Contributor

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    I was responding to Gomero in my post above on fusarium, (which I may have caused confusion, fixed now) but forgot to quote
    when he asked:
    I don't know that it's fusarium. I stand by my post re:
     
    Last edited: Mar 6, 2019
  18. Gomero

    Gomero Well-Known Member Maple Society 10 Years

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    Thank you JT, quite interesting articles, now I know that Fusarium sp. can also affect some maples. The association of PSH Borer with the fungus, as spread in Southern California, seems deadly affecting a large number of trees species. However the probability that the dieback in this Acer palmatum cultivar comes from Fusarium sp. is probably quite low, my educated guess is also that it is Veticilium sp. produced wilt.
     
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  19. emery

    emery Contributor Maple Society 10 Years

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    When I look to the source material, I see virtually every author in my library associates Fusarium with maples. Since I expect my friend @Gomero , your library is no less complete than mine, I'm surprised you haven't made the association. Let's look at some examples:

    Translating loosely, our mutual friend Benoit Choteau writes in his "Maples of Japan" (with pictures!): Fusarium (fusariumoxysporum) is mostly found in too wet environments or when the roots freeze. Plants in pots are very sensitive. A treatment with Aliette or with a product based on 'Prochloraz' can help. Etc.

    So there's your reference.

    In "The Gardener's Guide to Growing Maples," James Harris devotes a section to Fusarium, writing "This is another fungus that may cause dieback or loss of young plants. The disease affects young seedlings as well as older plants..."

    Vertrees/Gregory teach us in "Japanese Maples 4th Ed", in the section "Fusarium and Botrytis": "Fusarium, a fungus involved in dieback or loss of young plants, affects older plants also. Damage may occur at ground level, destroying the cambium at the base, or it may occur on twigs and limbs, destroying new buds and shoots"

    In "Maples of the World" Dr H.J. Oterdoom informs us that "Fusarium, Botrytis and Pythia are serious threats, as they are everywhere in the world in every species of plant. Frost damage or drought may initiate an attack"

    Finally in my limited research I see also that the OP's associate Neil Kenney opines in his "Illustrated Guide to Japanese Maples": "There are occasions when an established maple can break into leaf and half of the tree or a large section of branch fail to leaf, this is caused by the fungus Fusarium which shows itself as black streaks or patches on and under the bark of branches and at the base of the tree after entering through the root system." etc.

    Now neither of us believe everything we read about maples (or indeed anything else), but I guess the overwhelming evidence from our references is that Fusarium is an actor on maples.

    I never presume to offer an accurate diagnosis from a photo and won't here either. But since I don't know a good treatment for verticillium, and I know Aliette is effective against fusarium and phytophthora, I think Aliette is a good thing to try.

    -E
     
  20. JT1

    JT1 Contributor

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    @emery Aside from the stated books do you have any scientific evidence of a confirmed case in Acer palmatum? Could these author's be drawing from experience in growing other genus that are prone to fusarium and making that association mistakenly?
    (In some cases a mistake is made by one author or publisher and the others follow suit)

    I always thought fasarium wilt affects relatively few woody onamental species and my experience has only been through exposure with some fruit trees, veggies (tomatoes, peas, herbs like basil), and palm. Or like the links I shared it is spread by beetle into trees and transmitted to seedlings from the infected parent tree for example.

    I am always open to expanding my knowledge. I know, who am I to question what's written in books? But it would not be the first time I found something wrong in a book. With that said, it would not be the first time I was wrong either.
     
    Last edited: Mar 8, 2019
  21. emery

    emery Contributor Maple Society 10 Years

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    The authors I've cited are specifically talking about Fusarium in respect to Acer sp. Benoit Choteau at least is specifically talking about palmatum et al.

    If your question is have I done a survey of scientific literature available in open format on the web, the answer is nope.
     
  22. JT1

    JT1 Contributor

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    Sceptical but open minded I can't seem to find anything, but will post if I do...When it comes to new diseases / pathogens for genus and species; I have always found APS is a good scientific source.

    For example:

    First Report of Cylindrocarpon macrodidymum on Acer palmatum in Virginia

    American Phytopathological Society

    "To our knowledge, this is the first report of this pathogen on A. palmatum. Other reported hosts include grapevines (Vitis spp.) and apple (Malus spp.) (3). This finding demonstrates the ability of C. macrodidymum to impact an ornamental host and the potential for this pathogen to impact the ornamental nursery industry."
     
    Last edited: Mar 8, 2019

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