Japanese beetles are huge so you would have spotted them by now. The
small shiny black beetles do sound like flea beetles (if they jump).
They will leave a shot hole appearance to the leaf like someone
blasted your plant with a shotgun.

They will do some damage but are not going to reduce yield. Don't
worry about them. Keep searching plants during the day and also at
night with a flashlight to see what else turns up.

By the way, pyrethrins are a contact insecticide and break down
quickly in sunlight.

Forget about Malathion, Sevin, or Thiodan until you know what your
dealing with, and if its just flea beetle then repeat after me: Relax.
Don't Worry...