Theory on Flea Beetles

I`ve done a lot of searches but cannot find how the FB finds its food source.
FB`s can fly,jump and walk.
If we assume the search by scent then I`m wondering whether my theory may work.
A couple years ago my plot neighbour ask me If  I could smell that `foul smell`. It was coming from my Comfrey `juice`. This morning I was decanting a batch and some got on my hands. After washing them later I needed to wash a couple more times
So, could a comfrey dousing deter the said FB,methinks?
Not sure whether to douse the plant leaves or carefully dribble next to.

I don’t see why it would. FB probably have a receptor for a particular chemical that brassica produce and home in on this. This process won’t be affected by putting a strong smell on top. Worth a try though, nothing ventured, nothing gained.