Does this look like what you have on your parsley? It is a butterfly.

Here is a link that might be useful: Swallowtail Butterfly caterpillar

It sounds like horn worms aka the "tomato worm". Don't be fooled by the name; they love peppers and eggplants too. More info can be found here.

If that is what it is, I feel your pain. A trio of them ruined my best Jalapeno plant last week, consuming 1/2 of the total foliage on the plant over 24 hours and leaving most of the peppers exposed to direct sunlight burn. They are ravenously hungry beasts. If you get lucky enough to see one feeding, you will be amazed how fast the gulp down the leaves, going from one to the next to the next. They also eat the fruit - actually, they burrow into the fruit enough to ruin it for your own eating, and then leave behind a ruined pod carcass with a hole in the middle.

Best strategy seems to be to just go out in the morning and at night and pick them off. They are kind of hard to find, but can be found. They like to hang out on leaf stems, undersides of leaves, and occasionally on a main stem. If you search on horn worm, you'll get some other suggestions too, including corn starch, insecticidal soap, etc. But I was able to get them under control old-school style by just grabbing them and pulling them off the plants. They are destroyers of gardens, but few in number. (One or two can eat an entire plant, but once you get rid of them, they're gone). They're not like aphids - swarming in vast numbers. They're large and few in number.

As soon as you see those droppings, that's your alarm bell to examine every inch of the plant to get rid of the worms before they gorge.

Yep, hornworms. Nasty buggers, but they turn into the Hummingbird Moth (Spinx Moth) very beautiful. I've really don't like to kill them, but they can do a lot of damage in a very short time. I've been throwing them into the thicket and let nature take its course. Fiesty too, Iv'e seen them rear up(don't bite) and some say they make a cilcking sound.

Just to be clear, the parsley worms turn into a Swallowtail Butterfly, but these caterpillars are not what's eating your peppers.

Hornworms are big and fat and green and ugly and chomp on leaves. I find them very difficult to find on the plants. Just google them and you'll see some pics.

But please don't kill the parsley worms if you can find it in your heart to let your parsley go. The butterflies are gorgeous.

Thank you for your feedback. I saw a green worm that fits the description in my cilantro, which is growing in a pot next to the peppers. I'll make sure to investigate more closely.

BTW, why is the advice to check at night? I take it that at night they are out eating, but during the day they are above ground, correct?

Thanks again.