Brassavola nodosa dropping leaves at alarming rate...
 

Yesterday a leaf fell off my Brassavola nodosa. It fell off the pbulb that just finished blooming. I tried not to be too concerned but today a handful came off...I'm practically in panic mode. This plant had been thriving for me and astounded me with 3 gorgeous blooms that lasted almost a month or so. Some factors I'm hoping are the cause and that it's not something too serious are: since we moved at the beginning of April it has gone from bright, direct eastern sun to sitting on my fireplace getting bright shade at best. I also took all my mounted orchids out last week because we had a beautiful day and it wasn't supposed to go below 60...needless to say it rained overnight and got down into the mid to low 50s.
Should I start to panic, unmount it and start snipping old pbulbs (the ones that dropped the leaves are a little soft but def not mushy), or could it be from lack of light and getting cold and wet? Appreciate any help, Tha ks! :)

Two ideas:
One, treat with a copper-based fungicide
or
Two, divide the orchid into two...the part where you are losing leaves from the healthy part. Use more Calcium. I did this when I had the same problem...lost the part that was losing leaves but the other part is fine, thankfully.

It looks like a fungus attack. The stress of the cooler temperatures may have weakened the immune system. Good luck!

I don't have any copper based fungicides so I guess I'll be dividing it, poor thing :( Thanks so much for the input!

When I've mounted hybrid Brassavolas such as Little Stars, I've skipped the sphagnum and mounted straight on to wood and the plant thrived, producing many roots. Consider skipping the moss if you feel it is holding too much water and encouraging rot. You will need to mist the roots daily while in active growth.

So glad I checked in before getting started! I think that I will take your advice. I'm a chronic over waterer and I think this is my best course of action. Thank you!

Edited:
Its not coming off the mount without a fight and I'm afraid that'll do more harm than good. I removed as much moss as I could and I guess I'll just have to do my best to cut out the bad pbulbs... Wish me success please, I'd really hate to lose this one :(

I wouldn't remove the entire thing from the mount, just remove the moss and any sick pseudobulbs, plus one extra. I had forgotten it was mounted.

Done. I cut back as far as I could and applied a cinnamon and rubbing alcohol paste to the cuts. The poor thing looks so small :( Hopefully I got it all...

When I got mine from Andy's orchids, it just almost all of its leaves. I was in Boston at the time. I think the plant was very unhappy about the drastic change in culture. The plant never died and sat doing nothing until I moved it to LA where it gets much more light. After almost a year here, it has gone from its lowest of 4 pbulbs to maybe 8. It hasn't bloomed but at least it's moving in the right direction again!

It was quite amazing how fast it lost those leaves when it did, though. I thought for sure it was dying, but it wasn't.

The roots still look good. I'm wishing you luck as I would be very upset if I lost mine. Good luck.