Identification: Can anyone identify these brown spots on my maple trees?

Discussion in 'Maples' started by knottnancy, Sep 10, 2011.

  1. knottnancy

    knottnancy Member

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    Aldergrove, BC, Canada
    These spots start early in the year on the undersides of the leaves at the 'base' of the leaf where the stem is. They are initially a light color, raised, rough areas between the leaf veins. As the summer progresses, the spots become very dark brown, and the top side of the leaves start becoming dark and 'dead' looking. (difficult to describe...hopefully the pictures will work) Any help would be appreciated!
     

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  2. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Location:
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    Possibly Rhytisma acerinum but it doesn't look quite right for that.
     
  3. knottnancy

    knottnancy Member

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    Thanks Micheal,
    I don't think it's tar spots. It seems more like a scale. I used to think it might be some type of egg deposit on the underside of the leaves, but I never see anything 'hatch' out- no visible insects....
    A number of my trees are also getting brown splotches and curling edges and dying...might be stress from this heat, but I'm afraid of a fungus because of the cool, wet early summer. If it is a fungus, can it be treated? I have been diligent about watering these trees during the hot, dry weather since they are all in pots, so I don't think it is heat stress, but I hope I'm wrong!
     

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