I would look for a Katydid or a grasshopper. Those are my main enemies here.

If it isn't slugs/snails, it just may be caterpillars. Check closely on the underside of the leaves. If so, discard any that you find and apply BT.

Kevin

A picture of the damage could help identify the chard fiend.

Rodney

I'm in the Sierra Foothills. Really, the bugs have been almost zero lately and my raised bed is so new, hardly any bugs have discovered it yet. It's also a bit sterile as I put it on a gravel terrace; it's hasn't had time to get "real."

This is what my chard looks like. Huge chunks are eaten every day but I can never see what's doing it! No caterpillars around. I check many times a day and see nothing, just the evidence! I'm perplexed and dismayed :-(
See photo in link:

Here is a link that might be useful: Chewed up chard

Without knowing your chards' size and the pattern they are eaten, another likeLy suspect : VABBITS. They are around 365/24

Nope, can't be rabbits. I've never seen one here. That chard leaf is only about 4-5 inches long. Mysterious sections disappear at all times of the day. Like it's fine one minute, half chewed out an hour later. Then more, a few hours after that. I have a direct view from my kitchen only 15 feet away and I look out and go out ALL the time. It has to be an insect. It's eating one section of leaf at a time, one leaf at a time, one plant at a time, then goes on to the next plant when it's chewed down to the ground, over 2-3 days. I swear, I can never catch it in the act!

Accidentally posted twice...sorry.

This post was edited by daisies4ever on Tue, Oct 29, 13 at 1:15

Well, you think it is bugs and you haven't seen any of them, either. So maybe what you haven't seen isn't a good diagnostic tool here? :) Rabbit is my first choice. Are the stems eaten as well on these disappearing leaves? Then it is probably a rabbit or other mammal. If the thick main stem of the leaves is left behind and/or the leaves have a skeletonized appearance then insects are more likely. Your picture shows the early damage of a leaf, and I can't really tell from that.

I know, that's why I'm so worried my whole crop will disappear without my being able to do anything about it. This is definitely a stealth "critter."

Stems are eaten right down to the ground along with the leaves, which are *not* skeletonized. The photo shows the first typical phase: large chunk gone one day, bigger chunk later or the next day, gobbled down to the grround the next, then the next leaf gets started on and when that's gone, the next plant.

You know how leaf miners love spinach and chard, laying their eggs inside and killing the leaves? Well, I was wondering if anyone knew what loves to eat chard like this. Some bugs love certain things. Nothing has touched my leaf lettuce sitting right next to the chard. Whatever it is likes chard and not lettuce.

I've lived here for six months now and I've never laid eyes on a rabbit. I'm home most of the day, too, and see my garden from my kitchen window.

Since you say the entire stems are being eaten, that points to something other than insects or slugs. And since you say you don't see any rabbits, I'm going to say that it's mice that is eating you chard. You are unlikely to see a mouse, no matter how vigilant.

Rodney

All very interesting ideas. The weather just turned very cold so time will tell now. If I ever catch the thief and solve the mystery, I'll post it here. Thanks for the input.

Can you put a trap out for the mice?