/ Register

Welcome to OrchidsForum.com. We are a friendly online community for Orchid Growers all over the world. If you haven't joined yet we invite you to register and join our community. Hope to see you on our forums!

Total Noob- What is this disease?

Discussion in 'Issues, Disease and Pests' started by flyingSquirrel, Feb 9, 2012.

  1. Feb 9, 2012 #1
    flyingSquirrel

    flyingSquirrel Member

    Messages:
    76
    Likes Received:
    8
    Location:
    Seattle Area
    What is the disease affecting my Dend. jenkinsii in the pic below? How can I treat it? (unfortunately I can't really move the plant, as it is attached to the background of my terrarium. :bang: But there are no animals in the tank so if I must use chemicals, it might be doable)

    I'm not sure if it makes a difference in the diagnosis, but the plant is growing quite well, tons of healthy roots and new foliage. It's just the leaves that are showing this problem. As a side note, is it normal for the older leaves to yellow and fall off of the pseudobulb? You can see the far right leaf is yellow; it is on an older bulb

    thanks for any help

    [​IMG]
     
  2. Feb 9, 2012 #2
    KellyW

    KellyW Orchid wonk Staff Member Supporting Member

    Messages:
    6,563
    Likes Received:
    2,362
    Location:
    Redding, California, USA
  3. Feb 9, 2012 #3
    ZWUM

    ZWUM Bulbophiliac Staff Member

    Messages:
    1,435
    Likes Received:
    164
    Location:
    Exeter, PA
    Occasionally water droplets on a leaf can act like a little magnifying glass and give a small spot of sun burn, I'm not sure if the same is true with artificial light, but I suppose it's a possibility. If the spot is wet or mushy it could be bacterial or fungal infection.
     
  4. Feb 9, 2012 #4
    Jon

    Jon Mmmm... bulbophyllum...

    Messages:
    4,437
    Likes Received:
    107
    Location:
    Denver CO, USA
    Not enough airflow &/or fresh air.
     
  5. Feb 10, 2012 #5
    Ray

    Ray Orchid Iconoclast Supporting Member

    Messages:
    1,826
    Likes Received:
    592
    Location:
    Oak Island NC
    Sorry Zach, but I gotta call "BS" on that.

    If the droplet focuses light sufficiently to warm the plant tissues to the point of burning, the heat would be enough to evaporate the water - which, by itself, cools the tissue as it does. Water is an excellent thermal conductor. Don't forget that you can put a flame under a paper cup of water and boil it without burning the cup.
     
  6. Feb 10, 2012 #6
    Kitty

    Kitty AKA\Debby

    Messages:
    734
    Likes Received:
    16
    Location:
    Napa Calif.
    if it were my plant I would cut off the biggest spot as it looks active, for small spots I can often stop the spreading with a little cinnamon gently rubbed into the spot, several of my friends do this as well at I would say a 80% success rate. I have another friend who says he equates this to astrology, I said I'm a Taurus and I believe :)
     
  7. Feb 10, 2012 #7
    Uluwehi

    Uluwehi angraecoids, dendrobiums and more Supporting Member

    Messages:
    1,973
    Likes Received:
    124
    I agree.

    I try to never touch lesions like that for fear of spreading it. I do use cinnamon to treat any freshly exposed tissue and it's never let me down.

    Flyingsquirrel, use a sterilised blade and remove the diseased section of leaf, cutting only into clean tissue.

    Dendribum jenkinsii likes LOTS of air movement.
     
  8. Feb 10, 2012 #8
    Jon

    Jon Mmmm... bulbophyllum...

    Messages:
    4,437
    Likes Received:
    107
    Location:
    Denver CO, USA
    +1

     
  9. Feb 10, 2012 #9
    KellyW

    KellyW Orchid wonk Staff Member Supporting Member

    Messages:
    6,563
    Likes Received:
    2,362
    Location:
    Redding, California, USA
    I see one of your water lines in the photo. Is there a mister head that could be dripping on that spot?
     
  10. Feb 10, 2012 #10
    Marni

    Marni Well-Known Member Staff Member Supporting Member

    Messages:
    13,770
    Likes Received:
    3,567
    Location:
    Santa Rosa, CA
    Dendrobium jenkinsii is a monsoonal plant and does best when dry for the winter so is probably a poor choice for a terrarium.
     
  11. Feb 11, 2012 #11
    ZWUM

    ZWUM Bulbophiliac Staff Member

    Messages:
    1,435
    Likes Received:
    164
    Location:
    Exeter, PA
    Good to know that water can't magnify the sun enough to cause burnt tissue. My bro and I took an 'orchid class' at a nursery a few summers ago and that was mentioned. I never considered the validity of that statement, my bad!!
     
  12. Feb 11, 2012 #12
    Ray

    Ray Orchid Iconoclast Supporting Member

    Messages:
    1,826
    Likes Received:
    592
    Location:
    Oak Island NC
    Unfortunately, that's how a lot of bad info gets proliferated... The fact that someone at a nursery was spreading that is shameful.