They sometimes chew through stems of small seedlings or munch on parts of plant foliage around here. I've only tried putting a piece of wood over a moist spot of soil, then gather up the rollie polies that congregate under it later. I might try the wood ash idea, since I have a half whisky barrel filled with strawberry plants. They do chew on the strawberries sometimes. And maybe I'll try the beer thing, also. We don't drink beer, but I could buy a cheap can of beer just for this.
