Stem turning white......leaves dying

OK this is my first grow. I read up on everything I could b4 starting.
I got all the way to the 4th week of flower b4 running into a problem.
I searched everywhere, but couldn't find anyone with the same problem.
I have 2 plants tied down (lst) in a small closet, 400w hps, dwc, 10gal res, GH nutes.

I neglected my plants for about a week and when I looked at them the water was real low and much of the roots not submerged looked like they had fuzzy white stuff on them....
ALL the lower 1/4 of the leaves shriveled up and died, I then noticed that that the stem was turning white from the the bottom to half way up the plant. It's like spots of white covering the lower part of the stem....growing upwards....it looks like some type of disease, mold, fungus...I'm not sure.
The canope, the top 1/3 of the plant looks great, but I'm afraid cause it looks like the disease is growing up the plant.

So I changed out the water and nutes hoping they would recover. I also added som h202 hoping this would help. Not knowing how much to use, I added 25ml to the 10gal res.
It hurts to get this far and to start loosing my plants.
Someone please help me save my plants.

PICS!!! Pleeeeease?

I wonder whether you now have adventitious root nubs starting ?

The fuzzy white stuff could be tiny tiny root hairs. Rot is more brown or tan.

OK I don't have the best camera or shot, but I think you will be able to get the idea. Looks kinda like a bumpy rash on the stem.

Forgot to mention, the brown streak on the stem if from yesterday with my nail i scratched the white stuff off to see what it was like and today it looks brown.

Looks like that binding is too tight, looks like the plant stretched and ripped off the bark of your "tree" remove that binding and pray it lives. JMO :stoned:

actually the ties are not as tight as they might look there is space for growth.
the brown is just where i scratched off the white stuff. the white stuff is what im concerned about. its like a rash on the stem.

i hope i am not right,but it looks like fusarium wilt

I looked a few places and im not sure.
does fusrium wilt present itself with a white rash like symptom on the stem?

i beleive the browning is where the fluid transport system is clogged with reddish brown stuff,and the white rash is affects from it.thou it is strange cause usually plants grown in soil suffer from this

Lose the twist ties and replace them with something softer. Sharp edges can cut into the plant and let infection take hold.

I think the white bumps really could be root nubs. Are they shiny looking? Is your humidity high enough for the plant to try to air root?

And this one I am just guessing, but if you put a tie like that on too tight, does it work similarly to how when you want to air-layer a plant, you have to make a little slit in the bark where you want roots to grow?

At any rate, don;t scrape the bark off.

stinky is right I think
root nubs