Question
I got my orchid as a gift from my boyfriend on valentines day, and at this stage it was in full bloom. Since, the flowers have all died and dropped off. I didn't cut back the stems because at this stage it didn't seem necessary.

However, now one of my stems has developed brown colour with purple spots all along it. The leaves are fine, as is the other stem (it's a twin stemmed phalaenopsis orchid) but this one looks worse for wear.

The plant has recently been re-potted, but I can see a root sticking out of the mixture at the top.

What should I do about this stem? If I leave it too long will the problem spread to the whole plant? I don't want it to die as there is sentimental value attached to it.

Thank you.

Answer
Hello Tash,

While it is difficult to say exactly what might be wrong with your orchid plant, my guess is that the spots on the stem might be scale.  Phalaenopsis orchids seem to attract scale like a magnet.  Do these spots look similar to a turtle shell?  If they do, it probably is a scale infestation.  Also, look at the underside of the leaves to see if there are more hiding under them.  

You can try getting rid of the ones that are visible by cutting off the brown stem and also wiping the leaves with a soft paper towel soaked in isopropyl alcohol.  Doing this only gets rid of the easily visible scale but there may be many more lurking within the potting media just waiting to migrate upwards to the leaves.  To get rid of those, you will need to repot the phal. in some fresh potting media while also thoroughly cleaning the pot.  

If they are not scales, write back and I'll try exploring some other possible causes.  

Jim Kawasaki
San Jose, Ca.