The symptoms you describe could be a disease as you expect or it could be due to an insect pest. Pull up a few plants and examine the roots and lower stem core for signs of injury or disease.

I have a similar problem in a few broccoli plants this year and the culprit is a rootworm. I'm just pointing this out because worms are usually easier to control than bacterial or viral diseases.

Similar with cranberries. I haven't grown them but I believe there is a cane borer that may cause the symptoms you are experiencing. Once you locate the problem than the treatment may be a bit more complex. Many borer insects need to be controlled at a vulnerable stage in their life cycle, often months away from the time the damage is noticed.

You're right, I should have dug up a dead plant. So I just went outside to do that, and the two that were "dead" yesterday look MUCH better. Not great, but not nearly as bad as they were. Perhaps it was lack of water, and these few plants were affected when the others weren't? We got about 1/2" of rain Saturday. Anyway, here is the "better":
{{gwi:76088}}
{{gwi:76089}}

I will check on them this afternoon and see if they are melting in the sun, but it's nice and cool and moist under 6" of mulch.

I dug up one that died about a week ago of the same thing. Him I did try to revive with water, with no luck. I pulled him up and didn't get any roots at all, but he was very dead. The stem was hollow and there were plenty of ants around, but given how long he's been dead, I don't think the ants were the culprit. I dug around in the soil and saw no sign of pill bugs or any bugs other than the ants.

I am loathe to pull up a plant that isn't dead because I have so few left. Cats, it seems, like to eat artichoke seedlings. If I start them from seed again, I'll keep them inside until they are 6-8" tall and not tasty anymore.

Careful with transplanting artichokes. I've lost 5/5 artichoke plants during transplanting in the past two years. I'd make sure you have a good root ball (meaning plant in a small pot).

I found it.

I went outside and they were wilted again. Two more chokes seemed to be succumbing, so I uprooted the worst one. Roots healthy, but ants everywhere. I finally saw the little buggers -- aphids feeding on the stem underneath the mulch line. I am not sure how to treat for aphids down that far, since sprays won't work, but at least I know what I am battling now and can start thinking of a plan.

That explains the black ants. :P

Ants can be a boon or bane depending on the situation. These fall into the "bane" category, as they're protecting the vulnerable aphids for their honeydew. You'll want to make sure to get rid of them, too.

Ha ha... there's no getting rid of ants around here!

Out in my garden they are farming the aphids on my tomatoes big time. You can almost see the little blue overalls on them. It's a daily little 5 minute chore, but at least I can keep those under control because I can get to them to spray them off.

Since I am not anywhere near budding yet (in fact, the artichokes are a long shot anyway), I may resort to a chemical insecticide. Meanwhile a dose of neem may knock them back enough to save them until I can think of a better plan. Neem is so drying, too, though, the cure may kill the stressed out plants.

alibamanicole,

Please let us know how the neem works for you. I'm trying my hand at artichokes for the first time and seem to be having a similar experience. Thanks and good luck!

Well, except for a couple that haven't been affected, the 'chokes are dead. I suspect that anything I tried as far gone as they were would not have worked.

I have the 'globe chokes that survive everything here & am trying to swithch to the purple Italian but they arent as hardy & dieing from heat or? like you describe. chokes dont like heat/dry or transplanting but you can get away with traNSPLANTING VERY SMALL SEEDLINGS in cold weather or digging up & dividing mature plants in cold weather, if you are careful & baby them.