Mildow

Hello. Looks to me like, Root problems. Take a look at the roots. give the stem a gentle tug to see if it's rot. Smell the roots is there a weird smell. If you can find white roots when you fold back the cloth, then it's another problem. Like bud rot. Look at the root first. Chuck.

maybe nutrient burn and or root rot? that thing is dead and dried up. If you're going to use drippers to water your medium it needs to have a lot of perlite amended into it so the runoff can drain out properly. or only turn them on for a small amount of time if you want to stay in soil.

either way, don't smoke that.. don't extract from it.. throw it out.

ich muss Scrubbyjimbob zustimmen

Photo is too far away to tell us much. A diary would help too. If it's PM you'll see the residue. I have a feeling you got botrytis or some other type of rot inducing disease. It more commonly affects buds but branches can rot too and anything that was alive past the rot is gonna dry out and die.