I can't fathom that gravel paths would deter voles. I doubt that they would find the gravel uncomfortable at all.

Trapping is the only thing that has ever worked for me.

Mouse traps. Repeat as needed for as long as needed.

You can find a lot of information about vole control on the internet, most of it useless and the idea of a sharp stone barrier comes from outer space.

Fine mesh fencing is the most effective barrier there is for voles, rabbits, and other similar critters. Hot pepper (capsaicin) dusts and sprays have been shown to be effective as well. Mouse traps are kind of, somewhat, effective.

What damage is being done in the garden? Voles usually do not do enough damage during the growing season to be of much concern.

kimmq is kimmsr

What I do is put a little gopher gitter down the hole and cover with a rock. In a day or two I check the hole and if the gitter is gone so is the vole!!

"Voles usually do not do enough damage during the growing season to be of much concern."

Kimm, are you serious?

They are happy to nibble each and every ripe or near ripe fruit and vegetable that they can find.

I find squirrels and chipmunks do far more damage in my gardens than voles do. Although I find vole trails in the grass after snow melt I seldom see one, or signs of one, during the growing season.

kimmq is kimmsr