I'd look carefully for a caterpillar.
and then spray with BT.

Hmmm, I didn't see any caterpillars around... What's BT, I really wanted to refrain from pesticides since I have toddlers in my family and wouldn't want any health risks.

My experience with hornworms is that they can blend in well, even when they're huge.

BT is a bacteria, it's short lived in the environment, and only really effects the bugs that eat the leaves.

Here is a link that might be useful: Bacillus thuringiensis

My tomatoes aren't affected though.

I had a hornworm just once, and he was on my jalapenos. Lots of tomatoes in the yard. Peppers, eggplant, tomatoes, potatoes, all potential hosts.

Not sure about the hornworm here. Hornworms usually are much more damaging and will strip whole branches and not just nibble "some" around the edges. Though, cararose is right, BT is probably the safest pesticide out there outside of hand picking... can spray up to day of harvest if that tells you anything.

I'd go out at night with a flashlight. Slugs or earwigs are probable. Maybe even a bird or rodent.

Kevin

I had very similar damage on my jalapenos, bell peppers, and basil. Went out at night and found a swarm of june bugs going to town on them. They left pretty much everything else alone and disappeared after about 2 weeks.

I also get damage like in your pic on my basil & pepper leaves from little orangish redish beetles. They are some sort of Asian beetle. My extension refers to them as asiatic garden beetle. They only come out at night & can really damage my basil & pepper plants so I go out at 9:30 every night with a flashlight and pick them off & drop them in a cup of soapy water to kill them. I'm sure my neighbors think I'm crazy. They seem to come from early July to early August here. I hate them!

I have grasshoppers and Katydids nibbling on my sunflowers, peppers and sweet potato vines. I use a pair of garden scissor to cut them in half. Also the worst year ever for leaf footed bugs and caterpillars.

Sooooo BT... Where do I get it.

At any garden center.

Comes under various product names. Likely retail personnel will be able to help you if you ask for an organic caterpillar killer -- then check the label ingredient list.

BTW -- Bt is a dead bacterium. It's the toxic crystal that dispatches caterpillars but ONLY if they're half grown or younger. Totally safe for people & pets.

Another culprit could be slugs/snails. But normally they are more active earlier in the season when the plants are small seedlings or just sprouting. The thing about s &s is that they are out during the night. To find out you have to inspect at night with a flash light.

The orange-copper nocturnal beetles are asiatic garden beetles, and to me a good reason for you to check for them is that you have the same damage to basil and peppers. This is exactly their feeding pattern at my house. Also mint and sweet potatoes and chard tend to get targeted.