Posted: 15/02/2013 at 08:55
Sounds like wireworm to me (they aren't very wire-like). Very difficult to conrol, chickens are best I'm told. Common in ground converted from grass, they are larvae of the click beetle, we were plagued by them on a newly created allotment. No chemical control, they do disappear with cultivation but this takes years but can be hastened by growing sacrificial crops of potatoes, don't compost then though!