Does that mean the plant is safe for caterpillars? Absolutely not.
People are excited when nurseries stop using neonicotinoid pesticides. Of course! It’s a good thing. The question is whether we remember that neonicotinoids are only ONE grouping of pesticides. There are many pesticides that are not neonicotinoids.
Two plants can be grown exactly the same, next to each other, one treated with neonicotinoids and the other with a non-neonicotinoid pesticide. Caterpillars eating either plant will be just as dead.
Remember, the fact that a plant isn’t treated with neonicotinoids doesn’t mean it is safe for caterpillars.