Need help identifying this caterpillar please

It’s eating my Lilac bush. What is it and how do I rid myself of them?

The culprit.

Additional info: it leave a shiny, sticky residue on the leaves.

Google image search says canker worm.

Where are you located?

It looks a little like a lost sallow, but they seem to have a black band behind the head that isn’t apparent in your photo.

Does it have legs continuously down the body, or is the middle section legless like an inchworm?

Try asking Chatgpt or Gemini, I hear they’re really good at identifying species of animals

That looks like it may be it.

Central coast California.

It looks like it might be the Sallow too but that seems to be a northern thing.

Thanks all.

Google told me it is a Mottled umber.

Hmmm, you might be right. I really did try to google it, but my Google-fu has a lot to be desired.

Thanks

Wikipedia’s description of the range of the mottled umber doesn’t coincide very well with @Lucas_Jackson’s stated location:

The species can be found in western Europe from northern Scandinavia to the Mediterranean, then east to the Caucasus, northern Iran, Russia, Russian Far East, and Ussuri.

Wheras the fall cankerworm is more locationally appropriate (Alsophila pometaria - Wikipedia):

It is found in North America from Nova Scotia west to Alberta, south to Colorado and California

Thanks for that.

Regardless, as much as I hate spraying chemicals, I love my Lilac bush more so I must take action.

Does anyone have any experience with Neem oil?

No.

I am seeing recommendations of a bacterial pesticide made with Bacillus thuringiensis bacteria. Super-specific, only affects caterpillars and a few fly and beetle larva.

You might want to look at the University of California Integrated Pest Management site, which will help identify the caterpillar and also suggest solutions to control it. Skimming through that site, I’m thinking Omnivorous Looper is another possibilty (also a great band name), although it seems larger than the example in your photo. They suggest Bacillus thuringiensis as mentioned by gnoitall above, for both Ominvorous Looper and Fall Cankerworm.

OK, Bacillus thuringiensis it is. Just picked up some from Home Depot.

Thanks again.