By Rubic
United Kingdom 
My runner beans plants died overnight all that was left was brown stalks which died
23 Jun, 2016
Answers
They died overnight...? As in they were fine the day before and totally dead the next day...? If so, and unless you're having neighbour problems, they must have been sprayed or fed with something nasty by accident.
24 Jun, 2016
Maybe the snails chomped them, was there any Snail Trails?
25 Jun, 2016
that's odd. have been accidentally sprayed with herbicide? were they well watered? this could be the cause.
23 Jun, 2016