potato eelworm

Have to ask whether you are absolutely sure it is eelworm?

If the tubers themselves had holes in it was most unlikely to be caused by eelworm, which produce tiny cysts on the roots (and sometimes also on the tubers) causing the plants to weaken and die prematurely, with a much reduced crop depending on how long the plant managed to survive.

If it is eelworm then you have a problem (so do I!) because the cysts remain viable for up to ten years, there is no chemical control available to amateur growers and although I have seen some reports of certain plants being sown to "trick" the cysts into germinating and then dying due to lack of their proper host, I can't say I've found the evidence convincing.

Rotation will help a bit, but all you can really do is to either use a new patch of ground, or plant potato varieties with some resistance to eelworm (they're not immune, but manage to hang on better than others!)

That helps a bit, the only other good bit of news is that in my experience the damage seems to be worse in patches rather than consistently deadly throughout the entire crop.