Hairy white mold on vanda roots.

[Sommeil]

Thanks for the replies. I'm considering ordering some Physan 20 because bleach does sound a little scary to use. Anybody have any experience with Physan 20?

[aliceinwl]

I’ve used bleach as a disinfectant too. But, aside from disinfecting the vase I don’t think there’s any need to spray it on a relatively healthy plant with some dead roots that are decomposing/molding. You’re just going to create more tissue damage and avenues for pathogens to enter.

I have a Phalaenopsis I repotted last year from moss to bark, most of the old roots slowly died but it grew a vigorous set of new roots and is currently pushing new leaves and flowers. The old dead roots are moldy now. They’re just decomposing: once the process is done both the old roots and mold will be gone.

If you really want to help your Vanda get something like Kelpmax. I had some on hand and decided to try it out on my Vanda and it really jump started root growth. I’ve only used it every other month but the roots are growing like crazy.

[Sommeil]

Originally Posted by aliceinwl

I’ve used bleach as a disinfectant too. But, aside from disinfecting the vase I don’t think there’s any need to spray it on a relatively healthy plant with some dead roots that are decomposing/molding. You’re just going to create more tissue damage and avenues for pathogens to enter.

I have a Phalaenopsis I repotted last year from moss to bark, most of the old roots slowly died but it grew a vigorous set of new roots and is currently pushing new leaves and flowers. The old dead roots are moldy now. They’re just decomposing: once the process is done both the old roots and mold will be gone.

If you really want to help your Vanda get something like Kelpmax. I had some on hand and decided to try it out on my Vanda and it really jump started root growth. I’ve only used it every other month but the roots are growing like crazy.

See, the problem is that the roots still seem very nice and green so I cant really conclude that they are dead. But after what you said about kelpmax, I looked it up and sounds promising. I bought some
So here is my current plan of action: Bleach clean the vase. Physan20 on the roots. Kelpmax. Hopefully this will turn out well.

I didn't expect the mold to withstand two treatments of H2O2. Might have been a catalase positive fungus.

[aliceinwl]

Physan is still only going to treat the surface. If you really think you’ve got an entrenched fungus, you’ll need something systemic. Personally, it looks like whatever fungus you’re dealing with is just attacking dead and dying tissue. If it were mine, I’d do a wait and see approach before hitting it with more chemicals and try to optimize growing conditions.

It’s possible the roots were kept too moist in the vase before you acquired it. I kept my Vanda roots perpetually wet for a bit and one developed some black fungus in short order. Changing things up and letting the roots completely dry daily fixed the problem. The peroxide is also going to cause some tissue death at least superficially that the fungus may take advantage of.

If the fungus is attacking unhealthy tissue or getting a foothold because of environmental issues, it’ll keep coming back because spores present in the environment will recolonize. The important thing is to figure out why you have the fungus and fix the underlying issue or let it run its course if it’s just in dead tissue.

[Sommeil]

Well folks, I snipped off the dead roots and soaked the roots with Physan20. It looks like it did the job! Not to mention the flowers have not fallen off despite the torture I put it through!



I did a little bit more research and Physan20 is actually a systemic antifungal rather than a topical one.
Though I will say I noticed some leaf blight on my hydrangeas last night, so I sprayed some Physan20 on them and it caused leaf and flower discoloration. Poor guys.




I'm going to wait until the next scheduled fertilization time to apply the Kelpmax to the vanda, but it seems to be a proven tonic, so I'm just itching to use it right away!

So guys, thank you all for the help!

[Swimmingorchids]

1:128 on the bleach sounds better than 1:4 - probably stronger than what I disinfect surfaces with.

I find people recommending hydrogen peroxide overstate the dose too.

It is interesting that pretty much any orchid video mentioning hydrogen peroxide will say to use 3%. There is loads of them!

Yet if you research it for any other plant they tell you to dilute it down to 0.3% because higher will burn the plants.

So maybe orchids can tolerate 3% compared to other plants but I know 10 times weaker works just as well without burning the root tips.

Considering how careful you need to be fertilizing orchids I found it interesting to see some people recommend such harsh treatments.

[Sommeil]

Originally Posted by Swimmingorchids

It is interesting that pretty much any orchid video mentioning hydrogen peroxide will say to use 3%. There is loads of them!

Yet if you research it for any other plant they tell you to dilute it down to 0.3% because higher will burn the plants.

So maybe orchids can tolerate 3% compared to other plants but I know 10 times weaker works just as well without burning the root tips.

Considering how careful you need to be fertilizing orchids I found it interesting to see some people recommend such harsh treatments.

Yeah, I definitely got the idea from Missorchidgirl on youtube