curious spots on a dendrobium

[djuna]

windswept but otherwise sunnyblue summer greetings from finland...

i've been looking up on orchid sites trying to identify what may be ailing this noid dendrobium (phalaenanthe).

the spots on the leaves were present when i got these back in april. since bringing them out in the summer i have misted the leaves in the mornings. i cannot say for sure but it seems like the spots have grown a little in size but not in number.

based on what i could find out, possible causes are:
- brown rot
- guignardia/phyllosticta Leaf Spot
- fusarium wilt (the yellowed leaves)

as the spots are scattered throughout the leaves, might i need to lop off the whole leaf?

and will the plant survive if all leaves have to go?

diagnosis and advice from a more experienced grower would be greatly appreciated!