Thuja not doing well

Discussion in 'Gymnosperms (incl. Conifers)' started by Tercel, Sep 27, 2006.

  1. Tercel

    Tercel Member

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    I planted a Thuja a year ago, which is now about 7' tall. It was doing fine until about a month and a half ago when a couple of branches turned orange. Now there are more branches that are orange. All of August and the beginning of September we had lots of rain. Now it is dry so this week I started watering it every other evening.

    Is the orange color caused by lack of water or does the tree need fertilizer.

    Tercel
     
  2. GreenGoose

    GreenGoose Active Member

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    If the damage begins closer to the trunk and works out to the tip of a branch I would suspect mites. If the damage begins on the tip of the branch and spreads toward the trunk, i would suspect fungus.
    Because August and September were wet it seems to me a fungal blight is most probable.

    Does any colour come off on your finger if you rub an affected branch ?
     
  3. Tercel

    Tercel Member

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    Thank you for your reply.

    The damage seems to begin on the tip of the branch. Some of the needles (if that is the correct term for this type of evergreen) have white tips, as well.

    The color does not rub off on my finger. If it did, what would that indicate?

    Since posting my message, I spoke with a "master gardener" of an organization of garden clubs here in Albuquerque. Although he wasn't familiar with a thuja, he looked at the orange needles (leaves) and, after looking up fungus in a book, decided that is what it must be.

    I have bought some fungicide and will try it. Fortunately, the monsoon season is finished.
     
  4. Tercel

    Tercel Member

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    GreenGoose,
    I am embarrassed to say that I did not look thoroughly at the thuja. Fortunately, Just before spraying with a fungicide, I found two webs and a green worm, about 1" long. Also, the damage does seem to be starting at the trunk and working outward. In addition, in one place there is sap running from the trunk. And, some of the tips of the needles (leaves) have little brown spots.

    Would you please tell me the type of pest that has attacked the tree and what pesticide to use.

    Thank you.
    Tercel
     
  5. GreenGoose

    GreenGoose Active Member

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    I doubt that I can analyse the situation with 100% accuracy from my computer and would probably have problems on site as well.
    But these are my thoughts.
    Rusts will often leave colour on your finger when rubbed but other fungus will likely not and bacterial blights won't. So we will exclude rust on probability.
    OTOH, the brown spots are probably indicative of a fungal blight which can be treated.
    The interior of the tree may have mites or the discoloration may simply be the natural deterioration that occurs in fall when the new foliage replaces the old.
    What I think you can do is to first examine the foliage with a magnifying glass for the presence of mites. Even if you do not find mites, you can use a horticultural oil spray as prevention as well as correction.
    Secondly, spray the tree for fungus. The easiest anti-fungal to use is liquid sulphur and you would want to use that weekly for 4 weeks spraying till the foliage dripped excess spray. Copper oxychloride might be more effective and have a better residual then sulphur but should probably be applied by a professional.

    Finally, after a month of specific control measures have demonstrated some improvement, spray the thuja and all your garden trees with dormant oil mix as a preventative for the future. It actually helps to spray everything that is going to overwinter from small plants to large trees and the soils around them. Before you spray, rake and bag all leaves and needles from under the trees that have shown infection.

    The above is all do as I say, not do as I do. The probability is that the tree will clean up on its own after the atmospheric conditions that enabled the pests to grow are gone. The easiest and perhaps best solution is to do nothing other then the normal feed program.

    I hope that helps more then confuses you.
     
  6. jimweed

    jimweed Active Member 10 Years

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    Do note that it is very natural for the inner foliage on a Thuja to orange and defoliate each year. Spider Mites can be easily found if present, by shaking a branch onto a white piece of paper. Mite damage symptoms will turn leaf grey, brown, then orange. And messing with Mites can be your worst nightmare. By upsetting the balance of preditory Mites can cause serious infestations. Like Green-goose says about lime sulphur, apply a week apart for a month, is also your best chance at controlling mites if actually you did have any. In my opinion Copper is the best control for fungi and disease related problems on Thuja. But more than likely if your tree is only losing some inner foliage, its normal. Jim
     
  7. Ron B

    Ron B Paragon of Plants 10 Years

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    Caterpillar feeding would explain limited area of damage. Don't apply any chemicals until it is established there remains a need for them. Without a certain identification of a specific problem accurate selection and timing of pesticide cannot be made.
     
  8. jogardener

    jogardener Member

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    I have noticed what sounds to be the same thing on not just the old growth western red cedars in the green belt behind our property and neighboring properties but also on the younger ones within our property -- I just noticed it in the past few weeks and I am quite concerned because I haven't seen this before, it is definitely not coming from the foliage closest to the trunk it more to the bright orange color and nearer the outer edges of the branches. There doesn't seem to be any transfer of color when I rub the discolored branches. I tried to take a photo which shows what I am referring to, yet I am not sure how helpful it is, I will attach it anyway.
     

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  9. jimweed

    jimweed Active Member 10 Years

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    Hard to tell from the pic, but it looks to me like the browning is on the inner leaves not the newer growth? Which would be natural.
     
  10. Tercel

    Tercel Member

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    Today, I took some discolored needles (leaves) to the county extension horticulturist for his opinion. He thinks it is a fungus. He also thinks it wasn't planted correctly last fall and the roots are trapped (my word) in our horrible clay soil. In other words, not enough room was made for the roots and, according to the agent, I shouldn't have added compost to the soil around the roots when it was planted.

    I think I'll also resort to some prayers. I love my tree.

    Thanks for all your advice.

    Tercel
     
  11. Tercel

    Tercel Member

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    The county extension horticulturist also said he thought my thuja has seiridium canker when I told him that there is sap about 3" in length on the trunk.

    Tercel
     

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