Blue green spots on dendrobium roots and now Phal?? (Mold???)

[Nails]

Hello! This will be my first post on this forum. I hope I’m not repeating something that’s been answered elsewhere (I did try the search engine!)

Until recently I’ve only had phals, but in August I bought my first dendrobium and noticed there were blue-green spots on the aerial roots....although at the time I thought it must be some kind of paint or dye from the store.

On Sunday, I repotted my dendrobium and a Phal. I noticed that the blueish spots were also on the roots in medium and it seemed to me that those areas that had the spots were mushy, so I removed any affected roots. I sprayed the roots with hydrogen peroxide.....which I know is not ideal, but I haven’t been able to find any fungicide in my area yet, and I thought it would be better than nothing.

The next day, my Phal had two of the same blueish spots. I’ve attached pictures of the spots on the Phal roots (dendrobium aerial roots look okay so far)

Does anyone know what this is and what I can do about it?

[Ray]

Maybe I'm just not seeing what you're referring to, but those exposed roots look dead to me.

[Roberta]

First of all, no peroxide... it will strip the little hairs off the ends of growing roots, and tend to kill the roots.

To figure out what roots are viable (maybe not ideal but still helping the plant) and which are dead, water well. The living roots will tend to turn green (even if they have bad spots on the spongy velamin that covers the actual root, they're still hydrating the plant. If it stays brown or black (especially if shriveled) you can cut it. But on a new plant with possibly a poor roots system, don't be in a hurry to cut - even a bad root is better than no root. Once you have some significant new roots, you can clean up the sketchy ones.

[King_of_orchid_growing:)]

There's nothing wrong with those roots. They're alive.

Also stop with the hydrogen peroxide. It is not necessary and it can be harmful to the plant.

Those "white spots" are natural, don't worry about those, it isn't fungus.

The "blue green patches" might be cyanobacteria. They're harmless.

[SteveJackson]

Thanks for sharing.