Identity of caterpillar - Ask Extension
Hello!
I am hoping you can identify a caterpillar that I had found on my bronze fennel plant the week of June 9th 2024. I do not recognize it as a sw...
Knowledgebase
Identity of caterpillar #873687
Asked June 18, 2024, 6:08 PM EDT
Hello!
I am hoping you can identify a caterpillar that I had found on my bronze fennel plant the week of June 9th 2024. I do not recognize it as a swallowtail caterpillar. In fact, I think it might be a moth caterpillar. It had built a white silky cocoon-type structure on the plant. After moving the caterpillar's "home" and it to a bug box, I noticed the caterpillar retreated most of the time into its "home". Today, however, it decided to nestle down into the lining of the bug box. In the first picture below, the measurement between the 2 peach colored dots (at about 9:30 and 10:30 o'clock) is about 2 cm. The caterpillar is about that long. Thank you for any help you can give!
Montgomery County Maryland
Expert Response
Here are the two other pictures which I had difficulty sending in previous email.
Hi,
Unfortunately we are not sure what type of caterpillar this could be. There are so many various moth caterpillars and they can be difficult to identify between them. Our best advice would be to keep feeding it the fennel and see what it turns into.
Feel free to send back any cocoon or adult photos and we can try then as well.
Emily
Hi, Emily,
Thank you for getting back so quickly! I will continue to care for the caterpillar. Hopefully, it will make it to the adult stage and hopefully it will be one of the harmless moths. Recently, I was thinking it might be a black-patched clepsis...not a good thing to have.
I will send cocoon and adult photos if I am able to get any.
Thanks, again!
Sincerely,
Cathy
Although that moth's caterpillar does look similar to the one in your photos, the host plant listing for that species does not include carrot-family members like fennel. Either way, it is a native species of moth, and fennel does not have serious caterpillar pests (aside from gardeners who consider the Black Swallowtail caterpillars nuisance pests when they are abundant).
Cocoon photos will not be distinctive enough, especially since Maryland is home to over 2,700 species of moth documented in the state. (There are only about 160 butterfly species, with just a handful of those being swallowtails.) The adult might have distinctive wing patterns to be identifiable, but we can see what emerges. Science-based ID apps like iNaturalist can also help identify adult insects.
Miri
Cocoon photos will not be distinctive enough, especially since Maryland is home to over 2,700 species of moth documented in the state. (There are only about 160 butterfly species, with just a handful of those being swallowtails.) The adult might have distinctive wing patterns to be identifiable, but we can see what emerges. Science-based ID apps like iNaturalist can also help identify adult insects.
Miri
