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Cattleya leaf turned blotchy brown/black and yellow and fell off!

This is a discussion on Cattleya leaf turned blotchy brown/black and yellow and fell off! within the Orchid Ailments / The Compost Pile forums, part of the Orchid Culture category; Hello Experts, I have three cattleyas and one has had an older leaf with dark ...

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  1. #1
    Velamen is offline Member
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    Default Cattleya leaf turned blotchy brown/black and yellow and fell off!

    Hello Experts,

    I have three cattleyas and one has had an older leaf with dark brown spotting and eventually turned yellow and died. I had made the mistake of turning off my fan and then, for the winter, using a heater at night to keep me warm (my orchids are inside in my bedroom under grow lights.)

    I realize that lack of air circulation can be bad for cattleyas as well as high heat during the night. The infected leaf fell off its pseudobulb, all yellow like a bruised banana peel.

    My question is, what anti-mold solution (I don't think it's insects) should I use?

    I think the infection is Acidovorax (syn.) Pseudomonas.

    The solution presented via this URL:

    Treatment for bacterial brown spot is straight forward, you must kill the bacteria and possibly change the environmental conditions to prevent recurrence. If the infection is localized, you can pour straight hydrogen peroxide over the infected tissue.

    If this does not stop the spread of the disease or the leaf is moderately to severely damaged, you will need to remove the infected portion of the leaf down an inch or so below any discolored area with a sterile razor blade. Next spray the plant and its neighbors with a bactericide -fungicide. Copper fungicides are an excellent choice, just don’t use copper on your dendrobiums. Consan, Physan or pool algaecide can also be used. Spray the affected plants as well as surrounding plants because the bacteria are easily spread from splashing water. Increasing air movement and decreasing leaf wetness can also help prevent an outbreak from occurring.

    Does anyone agree with this or not? Any other recommendations other than that made above for Consan and Physan? I would deeply appreciate it.


    Don "Velamen"

    There pictures are not of my plants but those pictures in them resemble what the dead leaf looked at. The plant that is affect/infected has elongated spots on the underside of the leaf. The newest leaf is thus far unaffected and I would like to keep it that way. Pics are attached.Name:  Cattleya 2.jpg
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    Last edited by Velamen; March 21st, 2013 at 06:45 PM.

  2. #2
    Katherine's Avatar
    Katherine is offline Senior Member
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    Do you have the leaf/ Could we get a picture of the plant and leaf? Were other Catts affected?

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