They are beautiful caterpillars.

I have a very small herb garden. The first year I let the black
swallowtail caterpillars be and they ate my dill to a nub in no time.
The dill never recovered, as it gets VERY hot here in the summer. So,
the 2nd year I resorted to dusting the plants with BT BT is a
bacterium which is toxic to caterpillars, but not to people, so it's
safe for herbs.

Good luck!

Tim wrote:

I have four dill plants, all about 16" tall. Yesterday, I noticed for the
first time tiny (1/4" or so) black with a yellow band caterpillars on my
Dill.

Should I pick them off? How much damage will they do?

I wouldn't mind have more butterflys, but not at the expense of dill.

Tim

"The words of the songue should have three gatekeepers:
Is it true?
Is it kind?
Is it necessary?"
-Arab proverb