One last leaf.

[Hstb7]

Please see photo. My Sogo blackadder has been blooming and thriving for years. Now it's down to 1 leaf and it looks diseased. Help!

[estación seca]

Phalaenopsis are warm growing orchids. It's close to a window. That leaf looks like it might have cold damage.

Have a look at a sticky thread here. From the left yellow menu choose Forums then Beginners. Near the top is The Phal. abuse stops hede. Read the first few pages.