What Is Eating My Dahlia??

Can anyone recognize what might be causing the damage to this bedding dahlia? I've ruled out earwigs and other insects. Every morning I find something has eaten the new petal growth on each
& ever dahlia on these plants. I have red bedding dahlias about the same height, right next to the
white ones, but the damage each day is ONLY to the white dahlias, not the red ones. I've set a Hav-A-Heart trap (thinking either a bunny or squirrel might be doing the damage), but haven't caught anything yet. Getting very discouraged, these were beautiful plants but I haven't had a "whole" flower
in more than a month!

Given the size of the nibbles I suspect an insect or slugs/snails vs rabbits, etc. I'm not sure how you're ruling insects in or out since the damage is happening at night--slugs and snails definitely do a lot of nighttime munching but I'm sure there are other possibilities as well.

Jolie, you may have grasshoppers. I see you are in Birmingham, 8b/9a also. There are a number of species of grasshoppers that plague the area this time of year. I have discovered them hidden deep in the leaves of crinums and other bulb plants and watched them creep out to munch on flowers and hide again to munch on bulbs.

I have noticed that they tend to come out to eat just past dusk.

There are also a number of caterpillars that enjoy topping off their feed with a few tasty flowers. And with the recent rains, probably a whole new hatching of slugs. I have also noticed a few scarab type beetles around.

So why not use Sluggo or Escargo plus a good contact spay? I would not hold back on the harsh spray in such a small planting.
You have more flowers about to open.

I would rule out rabbits. They usually stay closer to the ground. Groundhogs do not usually stop with a nibble. Do you have deer?

No deer, but never considered grasshoppers! Thought slugs & snails left slime trails? Might it be slugs even if I'm not finding any slime trails? Haven't tried Sluggo yet (truly
didn't think it was slugs), but will get some & give it a try. Already using a good contact spray, but so far it hasn't had any effect (spraying weekly plus spraying again after it rains).

The tiny snails and slugs leave a truly miniscule trail. hard to see if you are not searching for it and if it rains, it is gone. The grasshoppers leave no trace other than the ruined bloom.

You can trust Sluggo and Escargo.....both the same product. I've used it for years. I feel it works 100% while leaving no poison residule. On the 100%....Snails and slugs will travel quite some distance to feed. Repeated applications are needed to keep them out of their desired feeding areas. They will eat it. Problem areas will clear up quickly when directions are followed.

I've use it on hosta beds and on my whole one thousand square foot pumpkin patch. They love pumpkins as well as hosta.

I only recall earwigs, ever eating dahlia petals. I've found them after ling within the flower petals, after noticing they had been chewed.
Whereas deer would eat the entire blossom & likely some leaves too, in just one bite.
I'd think mice would be more interested in tubers.

Smashed one large locust the other day, but found that just overnight, crickets had been eating entire pots of newly germinated seedlings I'd just potted up & many others had been chewed on or completely bitten off.