Posted: 05/07/2013 at 13:39
Some of my sweetcorn plants look similar and I'm convinced that squirrels scrabbling around them is the problem. In some cases, they've actually snapped stems, in others it's as if they've pulled at leaves, leaving them looking ragged.
Might not be what's causing this to yours but if you've got squirrels nearby beware... I've tried putting netting and various around but they don't seem deterred.