It looks like spider mite damage, but if no webbing or mites are found on the underside of those leaves then maybe not?

Thanks. I thought of spider mites when I first saw the damage, but I don't see any webbing or signs of spider mites otherwise. I've washed the plants down, top and bottom, just in case that's it.

Might it be drift or overspray of some sort of weed killer?

Photo doesn't enlarge all that much from the thumbnail, but it really does look similar to some sort of sucking insect. I get masses of tiny(1-2 mm) green leafhopper bugs here that will do that to plants in the hot weather months. They jump up/fly when plants are brushed against.

Thanks, carolb! I was typing a long reply to you on my ipad... still saying I don't think it's spider mites, and it can't be weed killer because it's completely away from all neighbors' yards and I don't use the stuff. Then it occurred to me to go outside and look again. lol! omg, it seems to be a combination of flea beetles and little tiny green leaf hoppers! Maybe a few other things in there too. lol! I've never caught them in the act before, but it was a dewy 60F when I saw the buggers this morning.

eta: there are also lots of these little things... much smaller than the photo makes it look, this is the first I was able to photograph and I notice I managed to get two in the pic! What the heck are they?

I have the exact same thing on all my bean and cowpea plants every year. I always thought they were spider mites also. I just let them alone because I do not want to spray anything once the plants start to produce.

Because spider mites like it hot and dry, spraying the plants down with water slows them down.

tj

Soap spray might work...?

I don't usually do anything either, tho.

I don't think it's spider mites. The photos aren't showing it, but if you look closely at the leaf surface it actually looks like it's been eaten away. Mites don't do that. I think it's damage from a combination of the leaf hoppers and flea beetles and other little critters that I found on the plants this morning. I sprayed/washed the plants two days in a row with water, top and bottom, just in case it was mites, and now I'll let it go. I like to share with nature, live and let live, and all that. :)

The thing is, with spider mites, there will be fine webbing on the undersides of the leaves with tiny red or black/brown dots.

At least, that's my personal experience.

I’ve seen plenty of spider mites on plants inside and out, so I know what to look for, and there isn’t any webbing at all. I‘ve also checked many times for any tiny dark flecks I could find on either side of the leaves and they were not mites. Mites was the first thing I looked for when I saw the damage., but I just don’t find mites. I just went out to do a quick check again and found another flea beetle, another leaf hopper, one small aphid, and lots of those little fly like bugs. Absolutely no sign of mites.