I know it could not be used on edible crops but ant and crawling insect powder, seems to stop the earwigs on my Dahlias, have tried upturned flowerpots with straw (that falls out and gets all over the place) Jeyes fluid on rags near plants that does not seem to work. Now I just sprinkle ant powder over em and seems fine.
The traditional way of prevent earwigs getting into Dahlia blooms, and Chrysanths come to that, is to smear the stems with vaseline. 8)