I'm assuming it must be earwigs, because I've looked everywhere for worms and can't find any. I also have lettuce two rows over that I know earwigs are living in. The dammage occurred overnight and I know that earwigs are nocturnal mostly. I'm not ready to pull up all my lettuce, any other ideas? I'd rather keep things organic. I've read about traps, but since they have a place to hide already, I'm not sure that will work.