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Thread: Phalaenopsis Fungus - Please Help!

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  1. #1

    Default Phalaenopsis Fungus - Please Help!

    Hi All,

    I'm new to this forum and to orchids and happy to be here! I've searched these forums and the internet and see a variety of opinions regarding fungicides, and I'm hoping someone can help me figure this out.

    I rescued several orchids from the clearance rack of a popular department store a couple of months ago. They were all severely underwatered, except for one which was soaked. They are doing better now, but I think some fungus problems have developed.

    The first picture is the overwatered plant. I had to cut off most of the roots due to rot, and it seems dehydrated, but at least it's growing new roots. The fungus seems to just be attacking the medium in this one, and a plant telehealth service told me this type is harmless, but you can see now some brown spots are developing on the center leaf.

    The second picture (with my hand in it) is one of the others, and here it seems to be attacking the roots. I think this is a different kind of fungus? I tried to use cinnamon on both, but to no avail.

    I've seen various opinions regarding H2O2, Physan20, RD20, etc. etc. etc. and don't know what's right. What do I do?

    Thank you for your help!

    ~Orchid Newb
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  2. #2
    Real Name
    Ray Barkalow
    My Grow Area
    Join Date
    Oct 2012
    Oak Island NC


    That simply looks like a mold growing on the medium, and is likely unrelated to the spots on the plant.

    My recommendation is as follows:

    No hydrogen peroxide. It is entirely too energetic in its energy release and can damage tiny root hairs.

    Physan can be effective, but over the years I have moved away from disinfectants because they are indiscriminate, and now highly recommend living microbes sold as plant probiotics - analogous to using beneficial insects to kill bad ones.

    I have found Inocucor Garden Solution and Quantum-Total to both be effective. Q-T is also sold as the privately-labeled “Quantum Orchid” at a higher price.

    The microbes within them predate pathogens, secrete antibiotics to prevent future infections, and have various other beneficial properties, including growth stimulation. I have used both over the last 7-8 years, have seen essentially no rots of diseases in my orchids, tropical plants, flowers, shrubs and trees, herbs vegetables and fruit (a fig).

    Here are a couple of things to read about them:

    What do plant probiotics do

    Comparing plant probiotics

  3. #3


    Thank you for the links! This is some of the best information I've seen online, and all in one place. I like the natural and gentle approach too, and your examples of success with probiotics are impressive. I'll try it and see what happens. This may be a stupid question, but how can you tell that this mold is only attacking the medium? I can't count how long I had scoured the internet before finding this forum and still can't tell the difference between "snow mold" and something harmless.

  4. #4
    Real Name
    Ray Barkalow
    My Grow Area
    Join Date
    Oct 2012
    Oak Island NC


    How can I tell? I can’t, but years of experience gives me a “gut feel”.

    Basically, healthy tissue does not rot. Dead tissues (like dried moss, bark, and roots that have suffocated), can. Plus, many infections of living tissue are bacterial, not fungal, although secondary, adventitious, fungal infections can occur.

  5. #5


    In case anyone has a similar problem in the future, here is an update. The mold is almost gone! Thank you Ray for the great recommendation! I did nothing else except water using QT. I am still concerned about the brown spots on the wrinkly one, don't know what they are... but the root is slowly growing in size and there's a spike, and you can see the new leaf on the other one. All of the other orchids are also growing spikes and generally look very happy.

    Pics (they're wet because I just watered them):
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