What's up with my Jerusalem Artichokes?

I've got quite a crop of Jerusalem Artichokes still in the ground. Whether I harvest in Fall or Spring there is always a large amount that are being affected by something. It seems to be most prominent around a root node, though shades of red can be seen over some of the skin area also. I pare away the affected spots and sometimes follow what appears to be a worm hole. I've never run across a worm or any other sort of critter as far as I know. Other than being a PITA to pare away at them (I'm not yet ready to eat them otherwise), there's certainly enough for everyone(thing). I'm more curious than anything. Is it nematodes? Or something fungal? My growing conditions are usually on the wetter side and lots of clay soil.

i’ve got similar issues. the last two pictures of yours look like there may be some wireworm damage, which could be a pathway in for some kind of fungal funk. i don’t have details about what exactly your (and my) problem is.

Yeh, now that you mention wireworm it does look similar to what I've seen in my potatoes sans all the red splotches.