pteroceras semiteretifolium Black and yellow spots

[Orchid-Obsessed]

Please help me figure out what’s wrong and how to help heal my pteroceras semiteretifolium.

She arrived in the mail in March with the black spot on the stem/crown area, this week, I noticed the yellow spots on the leaf.

Thanks for your responses, here are more details.

Reported in orchiata bark (I removed the sphagnum moss-I thought maybe that was causing the yellow and black spots). I used distilled water since March, but I will have to switch to RO- 18.9 L of distilled water in jugs are not available in stores right now, day 80f, night 68f, fertilize once a week, grown indoors, east facing window 2.5 ft away from the window covered with sheer curtain and I put under grow lamp with 7 other orchids when cloudy outside, fan is on, not directly aimed at the plants, every 3 hours that’s on for 1.5 hrs. humidity range 40% to 45%. The plant is in a 1.5” pot, not mounted and not hanging upside down.

Image is not upside anymore - I hope, I re-uploaded Thank you.

[Roberta]

Might be a bit of insect damage, if it were my plant I wouldn't worry about it. That new root looks great.

[SouthPark]

Hard to say for sure what the cause is right now. Roberta could be right ----- insect damage is a possible cause.

What's your growing conditions? Temperature range, humidity, lighting levels ..... and do you went the leaves when watering, and is there air-movement in the growing area. And ----- growing indoors or outdoors etc.

We can see that the images are upside down ------ so that's ok! We won't assume that the orchid is growing upside down heheheheheh

[Roberta]

The medium looks appropriate - large bark is good. If you can manage a mounted plant, this species grows very well that way. If not, you do want a well-drained medium. It probably makes sense to repot it now at any rate - with that new root starting, it will establish quickly into whatever you use. Another possibility, to mimic a mount but allowing for a bit more moisture to be retained, since you will clearly be growing in indoors much of the year, would be a plastic basket (net pot) with loosely-packed sphagnum. I have found that combination dries very quickly and works well for Vandacous plants. My plant grows in bright shade - brighter than Phalaenopsis, less bright than Cattleya. It is fairly cold-tolerant, manages southern California winters a few degrees above freezing (Obviously not Canadian winter of course!) But if night temperatures get down around 10 deg C (50 deg F) or a bit below, it will be fine.