Your question was an interesting one that sent me on a fairly deep dive. Normally, I would have thought that such damage was due to some sort of disease, but in taking a closer look and viewing lots of sites, it appears that the flea beetle may be the cause. You can find some good photos closely matching the pictures you sent here: Utah Vegetable Production and Pest Management Guide (https://vegetableguide.usu.edu/insects/potato/flea-beetles ). You will also find an approach for managing them  in the Insect management Handbook (//pnwhandbooks.org/insect/vegetable/irish-potato/potato-irish-flea-beetle) or in this publication on organic methods of control: Organic Management of Flea Beetles (https://catalog.extension.oregonstate.edu/pnw640).