Looks ALOT like slug/snail damage. I go out at night with a torch and some salt, then i just pick em up and put salt on the exposed "foot". Its evil, i know, but i just love to watch them foam up then watch the blackbirds and thrushes feast on them the next morning! I also found that using double sided tape was good, wrap it around the spike and put salt on the exposed side. WORKS WONDERS!