I'd suspect earwigs or pillbugs first of all. Caterpillars, weevils, grasshoppers, and slugs are possibilities, too. Visit the garden after dark with a flash light and you may find the culprits at work.

what she said.. but if you focus close.. it seems to be the older leaves.. not the newest ones...

if so .. the bug that did the damage could be long gone ...

do not use chems.. until you actually find something to kill ..

when these things are a few feet tall.. that damage is going to be irrelevant .. do NOT lose focus of such ..

ken

Those plants look fine. Unless you want to need a hazmat suit in your yard, you spray enough of anything to stop critters from taking a bite of your plants sometimes. Comparatively (to the number of critters out there) very few leaf-chewing situations result in death of the plant. A lot are easy to stop by just picking the critter you find off the plant and throwing it into the lawn. Some can be knocked off with a stream of water. There are beneficial bugs that eat about any kind of plant pest but you have to be patient at first. They won't show up until there's a tasty meal.

Agree with Ken and don't think those lower leaves will still be on the plant later. Usually my sunflowers lose the lower few leaves by the time they are flowering. Perfectly normal.

Thank you! I wasn't going to use anything on it, just wondering and praying they survive. By the way, I thought earwigs only ate dead, decaying material I've seen a few of them but not on the sunflowers. I also put out a roll of wet news paper hoping to catch the culprits..I've only seen one tiny slug and he was on the edge my compost bin.