Would appear to be the work of slugs but that is just a guess as they can often be found in wood based mulch. At this point it is only appearance damage and little to no threat to the plants.

The first rule of pesticide use in the garden is first you have to ID the pest. Until that is done there is no way to know what pesticide, if any, should be administered. So you will have to do some exploring at night with a flashlight to first ID the pest.

Once the pest is identified, then you evaluate the damage done. If it is severe (it isn't in this case) then you choose the pesticide that is the least toxic and specific for that pest.

Dave

Check also for EARWIGS. They are not as bad as slugs but are snicky. They can run and hide. They eat mostly lower leaves, even the old ones. While slugs prefer tender leaves mostly. Big slugs would eat the whole leaf. Small slugs may have a pattern like seen in the picture.
It is easy to find out if the culprit is slugs/snails : Just go out after dark with a flash lite and look very closely with patience.

On the other hand, if your peas are a couple of feet tall, those lower leaves being eaten is not going to do a great harm. Unless some of your other greens are also being eaten. Then it is time to identify the culprit and take action.

It does not appear that your peas are close to the 30 percent defoliation level, which is how much damage is needed to affect productivity. The mulch is harboring slugs, earwigs or both, so I'd be inclined to simply do a little first aid by sprinkling diatomaceous earth under the vines between rains. I love peas!

Being an organic gardener, I try to be pro active. By that I mean, I watch the garden for any problems that are just starting and get busy taking care of it before it becomes a bigger problem. I agree with Dave, that the first step is to identify what the pest is. I've had damage from earwigs in the past and couldn't figure it out until I went out with a flashlight at night and then ohâ¦so that's what's been doing it. :-) At that point, I will search the internet for a solution that doesn't require a pesticide. In the case of earwigs, it's a simple cup of soapy water and with a gloved hand, just knocking them off the plant into the soapy water. About four nights of that and I could hardly find an earwig in the garden. End of problem.

Oddly, one instance of not following my own rule to act quickly allowed for a solution without my intervention. Aphids. I kept seeing them and let them build up and the next thing I knew, I started seeing ladybugs in the garden and voila, no more aphids. Aphids also can be controlled by just knocking them off a plant with a stream of water. At this point, I don't worry when I see aphids, ladybugs eat a lot of aphids and I could almost worry that the ladybugs won't get enough food and go somewhere else. lol