Fusarium, botrytis, pythium, verticillium? What disease is this? (pics)

Fusarium, botrytis, pythium, verticillium? What disease is this?

If you do know, what would be my best course of action to take care of said problem? Obviously I killed this one, am I going to be forced to do the same to the rest if they show any signs of this infection?

Noticed some random and unexplained leaf death on the lower parts of the plant. It starts out as yellowing then to brown dead matter. Looked closer and I saw the odd looking whitish lesion/canker wound on the stalk that formed a sort of ring. There was also what appeared to be a bit of black progressing upwards the stem.

I cut open the stalk and this is what I found:

The discoloring on the outside of the plant lines up exactly with where this blockage appears inside the stalk...





Here is what it looked like before I cut the stalk in half:






Thank you for any and all help.

Anyone have any ideas at all? I picked up some Serenade for now to at least hopefully slow it down/prevent it on the other plants...

Still not sure what else to do though.

Bump..

Been doing some digging. Looking more like fusarium than anything. Also been digging on a way to kill it, if it all possible. Just like with powdery mildew, some say you can.. others say you can't. I can kill PM, so I am hopeful with this.

However I would still love the opinion of others who may have experience or at least some kind of fundamental knowledge on the subject.

Did you clone it and re-root it?
Look slike some kind of nute block, I think I am dealing with something like the same problem, where one of my nutes cooked the outside of the trunk and in turn pushed the inside of the plants main vessel closed.

I cloned and re-rooted (then isolated) one of them, yes. I plan on seeing if it gets the infection or not later on. Pretty sure it was sick when I got it from the club. Had a recent heat wave and I think it weakened the plant allowing the disease to rear its ugly head.