I don't think woodlice eat plants - only dead wood and the like. There are loads under my pots and planters and I haven't had anything eaten yet - it's more likely to be the usual garden pests.

No not woodlice, they only eat dead matter

Woodlice like the same conditions as snails and slugs, so if you have lots of woodlice, you're likely to have at least some slugs. A woodlouse wouldn't eat a petunia until after it was dead and rotting.

Thanx to you all..I think i was panicing as i had just put the petunias in.I will put some slug pellets down just in case the little bliters are having a good meal at my expence .Thanx once again .