Mass Phalaenopsis Root Rot Situation?

[jje10001]

Reply in the comments to keep things clear:

Originally Posted by Roberta

Photos?

Examples of darkened, rotted roots- they take on a mushy dark brown-green form, sometimes with fungal filaments growing on them.



Nearly all the roots on this side of one of my phals are darkened and mushy-looking.


The roots/medium smells rank (even ammonia-like), and even some of the lighter roots are soft and tear easily from the root strands.


An example of what was left after clean-up on one of the phals, removing all mushy bits.

Originally Posted by Roberta

When were these particular plants repotted?

They were recently repotted, over the course from January-now. Some were potted in as little as a month ago. So the medium is still relatively fresh, though some of it has been kept in moister conditions.

Originally Posted by Roberta

The fact that others, that were drier, don't have the problem is a big hint that the medium went bad.

Definitely moisture has to do with it, I have some that were not yet repotted from their sphagnum cups which are untouched, and another potted in leca which is also untouched.

But the simultaneous infection and appearance of root rot throughout several otherwise healthy growing plants, all at once, makes me suspect that this is an introduced infection that thrives in moister environments.

One thing that I noted is that several of my other phals not located near these affected phals did not seem to suffer from any of this root rot.

Another note is that I added a small amount of Dynamite slow-release fertilizer a few months ago to many of these plants (which are watered with plain tap water)- I wonder if there was gradual nutrient build-up which ended up exploding into this current issue? I recall that overfertilizing can cause a lot of these issues as well.

Overall, I think this is a infection that spreads plant to plant, or via the air. However, I'm not sure as to what exactly it is, nor of the way to treat it.

Originally Posted by Roberta

I hope that you have not been sharing water amount the plants! That can spread a problem from one to its neighbors very fast.

No water was shared, but they were in relatively close proximity to one another. The windows were open throughout this month, and a fan was running in the room.