My arborvitae are looking so ill, please help

Discussion in 'Gymnosperms (incl. Conifers)' started by lola, May 26, 2011.

  1. lola

    lola Member

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    Hi guys. I don't know if they are dying or what. Sorry for the long post - I just wanted to give you all the info I had.

    I know the following:

    There are tiny orange/yellow scales on the leaves, and about 5% of the leaves in my 3 tall cedars are a rusty brown colour. When I touch them, they are sticky and have black sooty mold on them, and I've also seen some small patches of white in the same area. I have read that the mold follows the scales due to their honeydew secretions.

    But, I also noticed that most of the middle of the trees' trunks are covered in the black mold - almost looking solid black - but powdery. I have obviously been negligent here. Could the trunk mold also be due to scales - are they possibly all over my trunks and I just haven't seen them?

    They grow on a downward slope of maybe 10% from my water runoff from the roof. When I purchased the house and they were spindly and small. There has been growth every spring/summer amounting to about half a foot a year, and most of the leaves - about 80-90% are a nice green.

    The bottoms of the trunks have in the past been damaged by the caretaker's hand-mower, and possibly also by mice - but, the growth has been consistent despite this.

    It is now probably too late to catch the scales moving, - is there anything I can do to make sure that they don't die? What about cutting the tops back for a more healthy tree, or thinning them in the middle...near the trunks?

    Thank you all in advance for your assistance.
     
    Last edited: May 29, 2011
  2. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Re: My cedars are looking so ill, please help

    Can you post some photos?
     
  3. lola

    lola Member

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    Re: My cedars are looking so ill, please help

    Okay - here are the pics - you can see the scales - young, and old dry ones as well. Also, you can see the white patches in at least one pic. There are 2 pics of the lower trunks as well. You can see in those pics the damage that was done by either rodents or the hand-mowers.

    The pics I've sent are specifically of the damaged areas, but the other side of the trees looks very normal - with very little brown leaves, etc. There's 3 cedars about 3 feet apart from each other.

    I am the one that removed the branches from the bottoms - and they never grew back there.

    I hope someone can help me out here. Is there a spray that would work - I understand that it would probably take several applications.

    Oh - and can anyone help me identify these cedars - then I could do some research on them myself. Or, perhaps the exact variety doesn't matter in this situation.

    I live in Manitoba, Canada.
     

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  4. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Re: My cedars are looking so ill, please help

    They're arborvitae (Thuja occidentalis), not cedars (Cedrus) at all (a regrettably frequent naming / identification error).

    Looks like you have a range of fairly minor problems there, which are perhaps combining to make the trees less healthy. In pic #1, there are some scale insects (which suck the tree's sap), and also sooty mould which is a fungus that grows on the scale insects' excreta and looks rather unsightly but doesn't do any serious harm of itself. Pics #2 and #6 show more sooty mould. Pic #3, dead shoots, sorry I can't tell what's caused this. Pic #4 looks like some old mechanical damage, maybe someone hit it with construction machinery or a ride-on mower several years ago? Pic #5, the bark looks OK, that's just the normal way the fibrous bark splits as the tree grows.
     
  5. lola

    lola Member

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    Michael F. - thank you for the ID, and the detailed explanations of what you see here - I sincerely appreciate it. (I just assumed they were cedars. :) )

    I thought that the dead shoots could be from the scales - no? If not, perhaps it's just our winters here in Winnipeg - sometimes it gets to -40C and I don't cover mine up with burlap - some people around here to that all around the tree to protect them from freezing, and maybe the browning that comes from that.

    I'm amazed that this is considered minor - it looks so bad up close ... I guess I should go looking for a scale-removing product, right?

    Thanks again. Any more info anyone I would still appreciate it... Is there a natural product that would help, or one that's at least not as toxic as some of the stuff out there?
     

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