First question, where are you?
What are the general conditions where you're gardening? Soil type, surrounding countryside, and how large is your garden? What else are you growing, and has this only hit the potatoes so far (of the crops?)
I am in Texas. I have seen this bug before, but never paid much attention to it - until I saw MILLIONS of 'em!
I searched a little bit online in "bug identification" sites but could not find it. Potatoes are members of the "nightshade" family - right? And we have a weed that is of the same family - they have stripped it too. THey have not found the tomatoes (also nightshade) yet, but I am assuming they'll be next - which would be OK, actually since the tomatoes looked like crud, anyway!!! (See my other post!)
I doubt any organic remedy is available to stop/prevent this. They did it overnight. I will be digging all the bare potatoes today.
Our BIG crop is black eyed peas - they grow well in this cruddy soil that we are gradually improving. If they stay away from them, I'll be happy. THe potatoes were right next to them, and they just passed right over them. I WOULD like to know their life cycle though to see if there's any way to disrupt it.