Garden Pests and Diseases: HELP! Mystery Diner is devouring my annuals, 0 by SW_gardener

SW_gardener wrote:
Hello, I was wondering if somebody here could help me figure out what is eating my annuals? Whatever it is leaving the perennials(mostly) untouched but my Zinnias, Petunias, Delphinium, Basil and Snow on the Mountain are the main ones being dined on. Especially the Zinnias and Petunia. One thing all these plants have in common is they are newly planted so I figure they must be under stress due to all this cold rainy weather we've been having. Now getting to the possible culprits........believe it we don't have any earwigs and potato bugs are fairly scarce too. However we DO have slugs and these little black snails but the plants in question don't really have any slime on them so I was trying to figure out what else it could be??? I check the garden very frequently and never find whatever it is so maybe it comes out at night?? Anyways, here’s some pictures of the damage so any help would be greatly appreciated!

Thanks,
Steven

#1 zinnia leaf