In case it helps, this is the earlier thread. The picture of the larva is better on here because it shows spots which may help with the ID.
The thread "Strange worm on my carrot leaves" in
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A spotted caterpillar that resembles this is the carrot seed moth, Sitochroa palealis, and it does make webbing. As Robyn said, it isn't listed as eating leaves though. I went through the book Caterpillars of Eastern North America and nothing resembling Robyn's picture was listed on carrot.
