Your picture could be my picture, except mine is from a month ago. I left them alone though. Always having a problem bringing in the Christmas boxes from the garage, seems they like to hang out on them.

Brown Marmorated Stink Bug is a destructive non-native invasive so I have no problem with killing them.

For the second year in a row, my wafer ash problems are being caused by potato leafhoppers AKA Empoasca fabae. Leaves are loaded with these leafhoppers.

I just looked them up... sorry you are dealing with them!

It's important to learn the ID of common insects, not only to protect the beneficials, but to eliminate the pests!

I have both pests mentioned in this thread, that darn non-native stink bug and the potato leaf hopper. We never had stinkbugs in the house like we have the past few years and all through the winter. I'm kept busy in the winter just trying to wipe out all of the stink bugs in the house. At first I thought that they were coming on in pursuit of those darn invasive Asian beetles that resemble our lady bugs, but I just think that they're looking for a place to spend the winter just like those darn beetles do. They're both a huge nuisance and we spend a lot of time in the winter trying to keep bot of those foreign bugs at bay.

Now, the potato leaf hoppers...I hate those too. I planted wafer ash here about 7 years ago and i never had a problem with those darn things up until 2016 when they started showing hp here. We would like to have the wafer ash tree leaves to feed the Giant Swallowtails that we bring in to raise, but the potato leafhoppers are always on them, with them getting worse as the summer goes on. They're really bad now and when my husband was mowing he said he had dozens flying in his face as he went past one of the trees. I have at least 8 trees with most of them being only about a foot tall, but there are two that are a fairly nice size (a little taller than me). The leaf hoppers have the trees looking absolutely horrible. I have kept a few of the small nice-looking wafer ash trees covered with tulle to help keep the bugs from getting in there, so we have a least some leaves to feed the Giants. I have other host plants to feed the Giants, but it really makes me mad when I can't use a plant for the purpose for which it was intended. I think I'll have to buy more tulle to cover more trees next year. I'll also have to keep them cut to a reachable level (and a size that I won't grow poor buying tulle). I imagine I'll have to replace it every year or two.

Just thought I'd chime in saying I can relate to the bug problems.

Well darn. I just looked those up, and while I don't see them on my wafer ash, I have brown ones that seem to hang out on my rue :( I don't see major damage, but will let them know that the rue is for my butterflies and to please move on.

You'll be hard presses to find anyone who would fault you for offing those little stinkers!

Are those predatory stink bugs? I think one of my Monarch cats was murdered by one, a couple weeks ago. I couldn't find the culprit, but I've seen that damage before. An article was saying that predatory stink bugs are a big help to gardeners. Well, not so, if the kind of gardening you do is butterfly gardening.

Well heck - I DO have potato leaf hoppers on my wafer ash :(

It doesn't appear to be a bad infestation yet. I'm looking into Aphidius colemani , an aphid parasitic wasp. I am trying to find out if they would go after baby swallowtail caterpillars. Does anyone know for sure?

I hope they only like aphids, because they sound like they'd help my poor milkweed as well. Lacewings are another aphid killer and I do see their eggs on my milkweed, just not enough.

Here are some pretty photos I took of lacewing eggs a few years back - you can click on the pictures and they'll enlarge:

An aphid parasite won't go after caterpillars. Baby lacewings might though. :)

Let Fori take the helm and stear for awhile. Then it should all be up to standards, right FORI????? I've seen some weird screennames, but you've got to be kidding me?????

After some investigating, what I have are Two Marked Treehoppers. I noticed some white "something" on a branch, looked like fungus, but it turns out to be the treehopper's eggs, encased in a protective coating. Really fascinating. Updated link with better photo:

Two Marked Treehopper egg covered with protective coating