The diagnosis is dahlia smut. Solution: cut it down and hope for the best. Clean well all tools used in cutting to prevent spread of this vile invader of my garden.

But I still would like to hear if any of you have had this problem and what you did about it.

I've had something similar, but did not diagnose it as such. I cut below the bad part, and hope for the best. Sometimes I win, and sometimes I don't. I do know that if I do nothing, then I definitely won't win, so the odds are best if I cut.

Actually, I am considering doing the "surgery" to a couple of my dahlias that got infected with spider mites. They look okay at the bottom. There's not much else to do, but try.

Oh! Poochella, thats a mess! Never had that happen. My dahlis's haven't been that great this year. Yes, they were early but the Japanese beetles have been in their glory munching away at my flowers and the extreme high temps here have been hard on the dahlia's' Some of them have only opened on one side, the bottoms of the plants have started to turn brown and dry up.

I would cut it back and keep my fingers crossed. So sorry

Willow

Poochella-- Are you on another sight and go by the handle of Names-All-Taken?? Linda

Yes that's me Linda. I originally registered as Poochella, and Poochella 1 or 2, but long ago forgot my passwords LOL, hence the new name as they would not let me register again under the Poochella name.

Update. The rotten beast is cut down. It was rotten all the way to the tuber and into the tuber head- probably two feet of interior rotting stalk. I cleaned out what I could. Dosed it with Lysol, sulphured the soil well and replanted it. The tuber and roots look good and solid so I will cross my fingers that I get some regrowth.
This was Pinelands Pet- new to me and one I really wanted to see in person.

I saw your message and picture posted on the other sight. I posted some pictures on there today.
Linda

I had EXACTLY the same problem. The center stem was mush, and smelled bad, too, right?

Since this is my first year with dahlias, I wasn't sure what to do, so my first step was to cut that stem out.

The next day, I went back and cut back the entire plant to the base, and culled it from the dahlia bed entirely. I replanted it in a very large pot, away from all other dahlias.

Yesterday, I noticed a small shoot coming up. I'm hoping the tuber is still good, as I didn't see any problem with it when I culled it.

Glad to know I'm not the only one. I've been trying to figure out what I did wrong. Do you have any ideas as to what causes this?

Sassy Stems

I have no idea what it was, but it's bagged and in the garbage can. My guess: bacterial stem rot, or verticillium affliction. I didn't notice a terrible odor because I was weeping (at the loss of Pinelands Pet)and my nose was stuffy LOL! Kidding. It would take something tragic like Ivory Palaces to go before I really cried over a dahlia. Did get a little misty eyed over Bracken Ballerina succombing to rot though, darn it.

I like your idea of keeping that tuber away from the others! Will be replanting mine tonight in a pot.

Here is a link that might be useful: dahlia disease chart