hbbusa....I don 't know off the top of my head, what would be the best replacement for rockwool applications. I'm not a hydro-grower, I run coco, so I'm certainly no authority. Sorry.

paht hed...I'm glad to hear it is not progressing. Maybe someone with more experience in stem rot will be able to give you a better prognosis. Lowering the surrounding humidity was a good move. Can you pull a little bit of the rockwool away from the stem at the affected point? I can see from the pics that the rockwool is not touching the lesion, but how about pulling just a little away from the stem below that point? I don't know how much it would help though....?

Hopefully you'll get some more help with this. I don't think I've done you much good .