Help ID Cornus Controversa Problem Please

Discussion in 'HortForum' started by MarkVIIIMarc, Aug 15, 2013.

  1. MarkVIIIMarc

    MarkVIIIMarc Active Member

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    Location:
    St. Louis, MO
    Hello, now I have a Cornus controversa showing some stress and tip die back.

    Background:

    My tree has been in the ground several years and came as a mail order transplant. It probably gets 6 to 8 hours of sun a day, my soil is pretty decent over a clay base and the tree is on a bit of a hill, it actually drains fairly well there. Overall it has been growing and flowering great.

    Problem:

    A few weeks ago I noticed the odd interior leaf showing fall color, no big deal I figured in August. A week later I noticed the end 12 inches of one branch and the next day another with discoloration and shriveled foliage. I cut off the affected areas, snapped a couple pics and cleaned my tool. A maple of mine about 200 feet away died from verticillium wilt in the early summer and my neighbor has a lilac in rapid decline with some kind of wilt about 50 feet away so I was worried and emailed pics to an extension agent. He figured it was not verticillium wilt as there were no streaks in the wood and Cornus controversa is resistant.

    Now in the last week another branch shriveled up and when I clipped it off I found that series of holes in the last couple pictures.

    Any ideas or suggestions would be appreciated, thank you.
     

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  2. saltcedar

    saltcedar Rising Contributor 10 Years

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    One twig looks hollowed out and I think I see borer exit holes?
     
  3. MarkVIIIMarc

    MarkVIIIMarc Active Member

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    Location:
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    They are definately holes I agree. The new growth of this species is a bit different than cornus florida. I don't know if it is hollow stemmed naturally. Maybe I will do some pruning and find out.

    Any idea what likes this tree? It is somewhat rare in Missouri so google is not much help. The Missouri Botanical Garden does have one so maybe I will run them a sample next week on my off days if I have a fresh example.

    I do have a good amount of imdicloropid (sp?) Quali Pro on hand which I use as an emerald ash borer preventative but I would like to at least know it is the correct treatment as bees love my Cornus controversa when its in flower.
     

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