We call it the "Colorado potato beetle". Its larvae eat all potatoes :(
Very dangerous if it gets on your potatoes. You usually have to remove the larvae by hand or spray them with some poison. I don't have it on my potatoes, he doesn't like horseradish, which I have a lot of in the field, but my mother has and she daily removes the larvae by hand...
oh ... now I see ... I was just think here I have seen this bug ... Yep this is this potato beetle :))
I thought it was a pest but couldn't remember what it's called. It's quite pretty though, even if it's not good for your garden.