Epidendrum with purple on cane - disease?

[elaines]

Hi! Please help!

Just noticed that my Epidendrum Helen Yamada 'Kauai Beauty' has purple edging up the side of its primary cane. I've included 3 pics. Is this normal or is it disease? This Epi is sorely underwatered and I know it's got some leaf spots but am wondering if it's salvageable or if I should throw it away before it infects others in my menagerie. I've not been good about taking care of the poor plants but am starting to do better. Just want to make sure, before I put this Epi in its proper light conditions, that it's not going to threaten the others in my high light area.

I just threw away a Recchera Honky Tonk Woman after figuring out (I'm pretty sure) that it had black spot. It had been quarantined to the kitchen with this Epi and a couple of other relatively new ones.

If the Epi is salvageable, do you think copper soap fungicide would be appropriate for the leaf spots or would Fungicide 3 be better?

Thank you!!!

-Elaine