At least, I think it’s fungus.
One of the potato plants is quickly developing a fungus – looking thing around its base. It’s the one in the packing box. It’s the only one that has any direct contact with the ground. It’s the only one that’s not blooming. And it may be the one that I watered with the yard waste can last week.
As of this evening, it’s toast. I’m going to bag the whole thing up and put it out for the yard waste guys, hopefully before it can spread to any of the other containers.