My guess is a fat green worm is enjoying your corn flowers. Search at the base of the plant just under the soil near the stem. Another sign of the worm would be scat or black droppings. If the damage is not a worm then deer, rabbits and slugs are other hungry pests this time of year. Try getting up early in the morning to see if you can catch the culprit in the act. Guess it really is the early bird that catches the worm. Keep growing, Marianne Binetti