Another potato question!

Have planted taters in bags - first time have grown them.  Seem to be doing really well however only one of the four plants has flowers on, but they all seem to be drooping.  Upon further inspection seems that something might be eating the flowers on the other plants?  Will my taters still grow?  Also am I correct in thinking that I cannot harvest them until the have flowered and the foliage has started to droop and turn lellow?