I am totally organic, I use chocolate X-Lax, it is safe for children and pets, will not affect or kill the plants in your yard.
Use a rod to poke a hole into the tunnel, use pliers or something to drop a piece of the laxative into the tunnel.
Push the soil back over the hole you made with a trowel.
Never touch anything with your hands.
This doesn't kill them, but it runs them off.
I have to redo mine every 3-4 years, work great.