I think it's a blister beetle. Ugh!

Oh dear, I think you are correct - I think your clematis is being attacked by Epicauta cinerea , the Clematis Blister Beetle. This bug seems to be both beneficial and not so beneficial - the larvae eat grasshopper eggs, thus the beneficial part, but....they can totally strip a Clematis of its leaves if an adult swarm attacks the plant. As for me, I didn't even know that Clematis had any insect pests, mine have been quite worry free for years, so now I have something more to worry about! Or at least to look out for....

I have not had the unpleasant experience of dealing with blister beetles, and I think I have been lucky as there are quite a few different types around and they seem to be capable of quite a bit of destruction to many kinds of plants, including vegetables. I read up on them after seeing this thread. Ugh indeed!

If there are just a few, you can hand pick them off of the plant - use gloves and or tweezers as, if you manage to crush one of them, their fluids are toxic and will cause your skin to blister. Apparently the beetles can "play dead" too, and fall on the ground when disturbed so you think they are goners, so dump them in soapy water or something to make sure they die. If there are a lot, you need to spray with an insecticidal soap, or something like Monterey Garden Insect Spray that contains spinosad. I also read that diatomaceous earth can be spread on the soil around the roots and even on the leaves of the plant to get rid of larvae and perhaps even some of the adults; it may be too late for that, though. (Of course, if you are not adverse to using something nastier in your garden, you can also use an insecticide that contains Malathion.)

Good luck! Hopefully someone with actual experience with this pest will chime in and let you know what has worked for them. I hope you keep us posted and let us know how you saved your Clematis!

Holly

I used the strong nasty stuff. My plant was well chewed and I wanted to save it for the fall bloom. Next year, I will be more prepared. It was so full this season with all the rain. The nasty stuff seems to have worked!

Glad that worked for you. If the weather cooperates next spring, perhaps you can use the diatomaceous earth to get rid of any larvae - too bad that is the stage at which the beetle is actually beneficial, but still, you want to protect your Clematis so what choice is there? From what I have read, the adults usually emerge in June or July, May seems to be the month to begin this application. Of course, if it rains all month again....

Yep, the rain this spring has made both the weeds and the insects very happy. Just starting to see baby grasshoppers around here, too, so something more to look forward to as far as garden pests are concerned! I think I would rather have them than blister beetles, but, really, could do without either!

Holly

Last year I used insecticidal soap on one side of my house with clematis and sunflowers. And the other side of the house with the (dawn detergent recipe). I was so disappointed on both sides. It puts a white color build up on the leaves when it's dry. It does not look pretty, it almost looks like they are dying in August but my flowers bloomed (sunflowers, black eye Susan , marigolds and wild flowers) I made about 20 vases and took all the leaves off because of that soap.