Nemah harvest - scab?

Just harvested one of my Nemah plants and the tubers all have bumps all over the surface.


Some background: I’m in zone 8a NC and it’s been hot and humid - a couple days in triple digits back in May, and in highs in the low-mid 90s for most of the last two months. We also had a dry spell followed by a couple heavy rains in the last few weeks, and due to unforeseen events I haven’t been able to spend as much time in the garden as I’d meant to in the last month, so there were a lot of weeds in the bed. I actually pulled this plant up by accident as I was weeding - I haven’t harvested any of my other potato plants to see if this is happening to any others. The vines have died already, so I don’t know what the leaves looked like.

Is this just a really bad case of scab? I don’t really know if my soil is scabby since this is a newish garden area - I only started growing anything there two years ago, and this is the first time I’ve put potatoes there. One or two tubers that I cut into had signs of either hollow heart or insect damage, but not all of them.

I’m wondering if they’ll be good to eat, and also if they’re okay to replant - some are sprouting already, and I was hoping to replant them this fall and see if I can grow them into December since winters are fairly mild here.

Wow! I have never seen that. I think it might be nematode damage. I’ll consult some books and see if I can come up with a better answer.

I checked several references and it looks consistent with nematode damage. Given your location, best guess is root knot nematodes. If that is correct, you would likely see nodules on the actual potato roots and on the roots of other plants grown nearby. They should be fine to eat and OK to replant in the same soil, but you probably wouldn’t want to replant them in an area that doesn’t show signs of nematodes to avoid spreading them. You could sprout them and remove the sprouts for planting, which ought to be free of nematode eggs.