Rhododendrons: Reddish brown spots on leaves

Discussion in 'Ericaceae (rhododendrons, arbutus, etc.)' started by lhendri479, Jul 1, 2007.

  1. lhendri479

    lhendri479 Member

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    Please see attached pictures. I just planted 12 rhodies, in the same place, same soil, same kind of mulch. One of the new plants (1 - 2 year olds) just got rings on their leaves. I used a very clean (sterile) technique when planting. I do not know what the rings are, if they are contagious, if it might kill this rhody, etc. Any ideas here? Should I isolate this one plant, try to control the cause of these rings, dig it out, dispose of it, etc? The underside of the leaves are a brown, reddish color (what I call a "bleeding" rhodie.

    Thank you very much.
     

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  2. Ron B

    Ron B Paragon of Plants 10 Years

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    Possibly mildew. This is now pervasive out here. Any moldy looking sections on the spots?
     
  3. lhendri479

    lhendri479 Member

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    No moldy looking section anywhere. These spots do not look moldy either. I will try for a macro picture.

    Thank you
     
  4. Ron B

    Ron B Paragon of Plants 10 Years

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    The moldiness would be on the spots. A fungus grows over the leaf, resulting in spots. Each spot is a little patch of fungus. Here when you look closely you can often see the fungal growth with the naked eye, such portions will have a dusty appearance until you get closer.
     
  5. lhendri479

    lhendri479 Member

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    new pics to view
     

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  6. lhendri479

    lhendri479 Member

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    I see no evidence of any mold. It just looks like it is ready to bleed !! Strange ! The only other rhody I have seen like this was one in the Blue Ridge Mountains, NC (where I live). That particular rhody was found in 1700 and is very unusual in that it is RED, not white, pink or purple. The NC and the American Rhody Society (I believe) are doing genetics testing on it to see what would account for this phenonenum. We were there a couple of days ago and the leaf looked very, very similar. Looked like it was going to bleed also, but the red vein went from the center vein out to the edges and I do not think it had rings. The President of NC Rhody Society said that if you cut the leaf, that it would indeed "bleed". No - we did not cut the leaf. We marked the rhody so we could get seeds this fall and then left.
     
  7. lhendri479

    lhendri479 Member

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    Have checked quite a few places regarding red-brown rings on my Rhody. Consensus of opinion is - "Necrotic Ring Spot" - Leptosphaeria Korrea (sp)

    After reading up on the above, I tend to agree with Dx.

    I wish to thank all who helped me. If you have anything to add, feel free to contact me.
     

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