Crimson King Maple & Powdery Mildew

Discussion in 'Maples' started by Chris Cooke, Jun 16, 2007.

  1. Chris Cooke

    Chris Cooke Member

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    I have a 35 year old Crimson King Maple, in the same location for over thirty years. For the last ten years it has been pruned to keep the height below 40 feet, and the width at about 30 feet. Last summer it developed powdery mildew, and spraying with sulphur was only marginally successful.

    This year, after a severe pruning and with much improved air circulation, all the leaves which initially came out on older branches were just fine. Suddenly last week new leaves began appearing on new branches and sucker shoots, AND ALL HAVE POWDERY MILDEW !! This is now being passed on to full-grown, previously healthy leaves.

    I am planning to totally strip all the leaves from the tree, and remove the new branches and suckers. I then intend to spray it with Safer's DEFENDER, repeating every couple of weeks until September.

    Is this likely to work ? Does anyone have any comments or suggestions ? Any assistance would be much appreciated.
     
  2. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    I'd get rid of it altogether (it can't be in very good shape with all that pruning), and replant with something less vigorous that won't outgrow the space you have. Maybe Mountain Maple (Acer spicatum).
     
  3. alex66

    alex66 Rising Contributor Maple Society 10 Years

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    Hi I have succes(my Crimson King is 10year old) whit Copper Oxide ,(the coulor is azzur and dust the use is whit water)sulphur is good for trunk and branch.I repeat this treatment every week for one mounths.alex
     
  4. blake

    blake Active Member 10 Years

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    Potassium bicarbonate is an excellent and inexpensive organic fungicide for plants afflicted with black spot, powdery mildew, brown patch and other fungal diseases. Just mix four teaspoons into a gallon of water and spray lightly (do not drench) on the foliage.

    Hello everyone, this is my first post. :-)
     
  5. emery

    emery Renowned Contributor Maple Society 10 Years

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    Goodness, Michael: a Gordian Solution! Large tree has powdery mildew, chop it down! :)

    I'm not sure the pruning has anything to do with the mildew. Norway maples are prone to it anyway. I saw one last year that from a distance I thought was an unusual cultivar like Walderseii, only to find out close up it was positively white with mildew.

    Chris, I don't think the mildew is life threatening. On the other hand I think stripping off all leaves is. At the very best this will weaken the tree. Think about how trees that are totally defoliated from caterpillars take several years to recover. The weakened tree is likely to be more prone to mildew, not less.

    Alex's treatment is good. I'd use Bordeaux mixture, every couple of weeks until the problem is under control. But you will need to keep spraying, and practice good garden hygiene like leaf collection for a while.

    On the problem of how to successfully spray the tree, unless you own a helicopter or maybe an old fire engine with tall ladder... ;)

    Good luck, I'm sure your tree will be fine.

    -E
     
  6. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Make that: "Large, mutilated tree, of a known serious problem invasive species, has powdery mildew, chop it down to remove the need to spray nasty poisons everywhere", and you can see my reasoning better ;-)
     
  7. emery

    emery Renowned Contributor Maple Society 10 Years

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    Believe it or not, I got your gist! :) Of course, as you know, I like these trees.

    I just love the image. Patient says: Doctor, my son has a head cold. Doctor replies: off with his head! That way the infection won't spread!

    ;)

    -E
     
  8. Ron B

    Ron B Paragon of Plants 10 Years

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    The topping IS causing the mildew, resulting sprouts being more susceptible. For a similar effect, cut a laurustinus (Viburnum tinus) back hard, late enough in the year that the regrowth occurs in summer. This procedure has the added appeal of making the now-moldy plant smell of cats.

    'Crimson King' branch sport Crimson Sentry mildews like mad on many sites here, but I have not noticed the parent cultivar being especially prone at all.
     
  9. alex66

    alex66 Rising Contributor Maple Society 10 Years

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    Yes Emery "Poltiglia Bardolese"in Italy,Welcome Blake
     

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