I feel bad no one is answering your question. I had no idea what a blister beetle was, so I looked it up. What nasty little critters! Be careful! I hope someone that has experience with them can help you!

For others that don't know what they are, see the link below.

Here is a link that might be useful: Blister Beetles

These are actually blister beetles which are specific to clematis. They seem to be active at night, I rarely even see the nasty creatures. As if causing blisters on contact isn't enough, I can't even locate them! It is unbelievable how much damage they can do in a very short period of time.

Kathy

Here is a link that might be useful: Epicauta cinerea - clematis blister beetle

Well, my agriculturist/entomology friend said this... don't know how helpful it is, but just in case someone finds it useful:

"Blister beetles can indeed give you a blister, and some of them can eject the blister juice out of their arse at you! I would just put netting over the plant to keep the beetle off. It might not have to be on year-round, but rather only when the beetles arrive."

Kathy,

I had blister beetles on my clematis last year. HORROR! As you know I don't spray, but I made the exception last year. I took a small spray bottle with malathion and hit the entire clematis with it. I feel fairly confident I kept the spray rather local... I didn't want to kill the beneficials nearby. The beetles were gone with one application. I need to go out and check for them today. I had found one a couple weeks ago inside my greenhouse.

I feel your pain.

Robert

Have had problems also with these,not every year, but last year was terrible.I tried Sevin which did very little. I have not had a problem this year but I'm glad to know that Malithion works.

Hi Robert,

I thought I remembered you having the same issue last year. If I remember correctly, about the same time you posted you had sprayed, mine seemed to disappear as well. I have not seen any additional damage for a few days so hopefully they are gone. I will remember the Malithion for next year. The first time I see the damage, I will spray immediately. If makes me heartsick to see what had been a healthy, floriferous Rooguchi reduced to a skeleton overnight.

Thanks for reminding me of what you did for them.

Kathy

I have the same problem. Only one of the clematis vines is attacked. It is the one that is a fall blooming plant with tiny white blossoms. The kill last summer was so bad it never flowered. I mix a concoction of water, dish soap, olive oil, horseradish, garlic and cayenne pepper. I can look up exact amounts, if anyone wants it, but I just toss them together at this point with less concern about amounts than about straining! I use several layers of an old T-shirt to be sure no lumps get through to clog the sprayer. I use this daily! If it rains, I might use it again. I spray from the bottom up and then use fine mist on the whole plant. Then I sit and wait to see if the bugs come out. Usually they climb up and out to the ends of the branches. I hold a small piece of wood to let them walk onto it. Then mash them with another piece of stick/mulch. I do not come in contact with the bugs or their innards! My first day treating the plant this summer, I killed 12 beetles. The next day, I killed 5. Yesterday I killed 3. Today I got three more. Interestingly, they were under the mulch at the roots of the plant. I stirred up the mulch with a stick. I had been told they lay eggs for next year, at the base of the plant, so their babies have yummy food when they hatch. So now I am looking for a killing agent to mix into the mulch/soil at the bottom. This spray doesn't seem to kill them, but it does annoy them and then I kill them. I also think it tastes bad so more bugs don't want to eat the plant. I tried a systemic product that is food and killer in one, drawn into the leaves of the plant. It did nothing.