Mystery Ailment on Phal Mini Mark?
 

I got this rather sickly Phal Mini Mark a few months ago as a rescue, and from the start, the crown looked rather sickly & damaged, some of the leaves had some strange chlorotic tips, and the mother plant had thrown out a basal growth. The plant was around 1 year old.

On the other hand, the roots were extremely healthy, so I immediately repotted it out of its gross-looking moss into a moss-bark mixture, and trimmed off the chlorotic leaf tips (sealing with cinnamon). The orchid was placed in an environment where it got bright indirect light + a constant temperature of around 20-22C/70F.

At time of acquirement:
https://i.imgur.com/bzvU5Ni.jpg
https://i.imgur.com/aI2KRmg.jpg
https://i.imgur.com/vnYxrRs.jpg

Month 1

Over the next month, the small leaves on the crown started to wither and become limp, and some strange pitting started to occur on the leaves.

I then removed the smaller leaves and then dusted the crown with cinnamon.

https://i.imgur.com/LWDLZau.jpg
https://i.imgur.com/0iY9BbM.jpg

Month 2

It seems like the issues with the mother plant are not stopping- in this month, the next topmost leaf is starting to yellow and shrivel. The rest of the leaves remain green and firm, and root system seems to remain healthy (I removed the top layers of substrate to inspect).

Furthermore, the leaf on the basal growth is continuing to grow, though it seems to have stopped working on its roots for the time being.

https://i.imgur.com/SFTCS8z.jpg
https://i.imgur.com/QiajNt4.jpg

At this point, I am considering some options:

I don't have any systematic fungicides, but I do have Physan20. No pests have been seen on this plant. There is no smell, and the pits remain firm, so I'm not sure if it's bacterial.

Do Nothing.) Keep as-is, and continue to monitor. I expect the mother plant to continue declining, but I will continue to topically treat any new issues with hydrogen peroxide and cinnamon.

1.) Remove the top & inspect for, and remove any potential rot. The best case scenario would be that this stops the decline, retaining at least two healthy lower leaves to help the basal growth continue its growth.

2.) Completely remove the top of the mother plant while retaining the roots, treating the basal growth as the main plant.

I know that I shouldn't expect any further growth on the mother plant, but my concern is that its ailment (if contagious), may spread to the basal growth. Any opinions as to what this problem might be, and what my course of action should be?

Mini Mark has 3 ancestors. They tolerate winter temperatures like yours but would be much happier at higher temperatures.

Your plant's blight looks like something user camille1585 had on her Phals. Look up her posts. And have a look at the Pests and Diseases page of the St Augustine Orchid Society.

Thanks- the room does get a bit warmer through the day as I have some computers in it, and it also gets much warmer in summer, so I hope it will be happier in a few months- as of now, it's been quarantining there from the rest of my collection.

As for camille1585's posts, were they these ones?

http://www.orchidboard.com/community...t=phal+disease

http://www.orchidboard.com/community...t=phal+disease

I often have a fan running in my room, but I suppose it's a good time to start cracking open the window for some fresher air.

I think the infection may be in the cracks of the leaves and around the crown, so I wonder if running that cinnamon-steeped alcohol mix into those could help...

I dribbled a bit of Safer's 3-in-1, and also a bit of diluted isopropyl into the mother plant's leaf pits and let it dry, hopefully the alcohol + the sulfur in the 3-in-1 will help knock out anything lurking there.

Update 5-25-2022:

I ended up carving out the crown of the mother plant, disinfecting the area, and leaving it to dry a few weeks ago.

https://i.imgur.com/bw9Gpku.jpg

However, it seems like there's another new patch on the mother plant that's darkening and drying out.

https://i.imgur.com/RN1XGfu.jpg

On the basal growth, the newest leaf has finished growing, and I see a new leaf starting.

https://i.imgur.com/P1uMMnn.jpg

And finally on the base of the new growth, a new triangular growth has started.

https://i.imgur.com/4umO6xk.jpg

In general, a lot going on with this plant- ups and downs.

Thanks for the continued updates. It’s always valuable to see how odd cases progress.

Thanks for the updates! I've had several Mini Mark over the years, and it seems that it is a rather susceptible hybrid, very prone to infections.

A small update 6-24-2022:

New leaf continuing to grow:
https://i.imgur.com/hi4C02c.jpg

Root growth restarting + new root, no movement on the triangular growth:
https://i.imgur.com/QHpRLh1.jpg

One of the older leaves withered off- instead of yellowing and falling off like in most phals, it seemed to have browned to a reddish tone instead, and did not fall off like most normal dying leaves. I wonder if it might have been that the dying patch at the base essentially girdled the leaf and preventing the plant from sending the signals to drop the leaf? Another strange case with this phal. No other changes so far with the remaining leaf, and I hope that the infection has ended now.
https://i.imgur.com/dlDouDK.jpg

I will also have to consider how to repot this phal in the future, as the new plant is essentially growing 90 degrees to the original plant and root system.

Good rescue! The mother growth is on its way out, though its roots are contributing to the "pup" which looks like it is doing very nicely. The crown on the mother growth was gone at the beginning, but orchids do have other strategies to survive, and producing offsets like this is an important one, especially with monopodial types (one growth point) Actually, other than aesthetics, having the growth at an angle is a good thing... in nature, that lets them shed rain water instead of having it collect in the crown (which can lead to rot if it also gets cold) By the time you repot (maybe in a year or two) the mother growth will probably be gone, you'll be able to orient your "new" plant the way you want it. When you do, consider letting it be at an angle, maybe not 90 degrees, but not straight up either. In the meantime, just let it grow.