What caterpillar is eating my raywood ash tree?

Question: These voracious little (1/2 to 1.5 inch long) caterpillars are devouring the leaves on the lower branches (up to 10 feet from the ground) of our raywood ash. Can you identify for me (images attached) and if you know any remedies, I'd love to hear!  Thanks!

responder: An Ask Extension Expert Replied May 24, 2023, 11:36 AM EDT
response: John: I am not sure what caterpillar this is. It does not match any I know that eats Ash trees. I have some questions that will help figure it out. How long has the problem been going on? How big are your trees? Have you seen any moths or butterflies around the trees. Let me know if you have additional questions. I will continue to work on this one. Thank you for letting us help you. Rich

responder: The Question Asker Replied May 24, 2023, 11:58 AM EDT
response: Hi Rich-- Thanks for getting back. This problem just started this spring. I've never seen this infestation before, although last year it was the ash whitefly, Siphoninus phillyreae, creating similar damage to the leaves of this Raywood. I know because I sent photos to your department to I.D. the problem (an example image of what I sent is attached). But this year, a new critter (the caterpillar) and noSiphoninus!  I'm feeling sorry for my Raywood ash!  BTW, the tree is about 12 years old, no structural damage, with a healthy upper canopy. It's about 30 feet tall. It's commingled with a nearby zelkova that shows no signs of infestation. I've probably picked off and destroyed about 250 caterpillars so far.Best, JohnOn Wed, May 24, 2023 at 8:36 AM Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied May 24, 2023, 7:06 PM EDT
response: John"  Where are you located. I am looking to see if you would bring one of the caterpillars into your local extension office.

responder: The Question Asker Replied May 24, 2023, 7:21 PM EDT
response: We're in Ashland. On Wed, May 24, 2023 at 4:06 PM Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied May 24, 2023, 7:53 PM EDT
response: I will be passing through Fri on my way to Weeds if it's possible to get some samples.

responder: The Question Asker Replied May 25, 2023, 12:33 AM EDT
response: Sure, that would be great.  I should be around all day Friday.  Here's my cell: <personal data hidden>.  About what time do you think you;ll be coming through Ashland? On Wed, May 24, 2023 at 4:53 PM Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied May 25, 2023, 11:03 AM EDT
response: Likely mid afternoon. My cell<personal data hidden> text only. Where is a good place by I-5?

responder: The Question Asker Replied May 25, 2023, 1:26 PM EDT
response: Rich--  If you pull off at the second Ashland exit (heading south), turn right onto Ashland St. and look to your right for a cafe -- The Wild Goose.  It's close to the exit and there should be parking.  I'm 5 minutes away. I'm thinking of providing a small leaf cluster with -- hopefully -- a number of caterpillars.  I'll put it in a sealable sandwich bag.  Does that sound OK? --JohnOn Thu, May 25, 2023 at 8:03 AM Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied May 25, 2023, 4:00 PM EDT
response: Yes, that sounds good. See you tomorrow