Potato Problem

My potato plants this year look pretty sad, despite N's best efforts.  They looked quite happy and healthy until sometime in May.  We started seeing some kind of red beetle on them that I never got around to identifying; R would help me find them (kid eyes are really sharp!) and I would squish them whenever we visited.  Then one day we showed up and it looked like one of the previously vigorous plants had suddenly died.  M, our community garden guru, said he was familiar with the red bugs and thought the death was caused by something else - possibly some sort of disease or fungus that was on the potato bud when I planted.  Now none of the plants really look healthy, and none of them have produced flower buds, which I think they should have by now. 

It's a shame, really, because the potatoes are the th,ing N spent the most time and energy on, hilling them up and looking them over every time he came to the garden this spring, and they're really the only thing in the garden that looks like it's doing badly.  Hopefully whatever is affecting the foliage won't spread to any tubers the plants produce.  I've been watering and hoping for the best.