Voles are no friends to Hosta. Their damage can be permanent and if you do not deal with the problem they can destroy your plants. Moles do eat grubs and have a more limited diet, voles will eat you hosta.
First, check for vole activity. You may see runner trails along the surface of the ground and once they get into your hosta you will start to see entire leaves that are separated from the base of the hosta (voles eat the white fleshy roots).
KEEP YOUR HOSTA GARDENS CLEAR OF LEAVES AND PINE NEEDLES SO YOU CAN SPOT VOLE ACTIVIY
Options:
#1: Cage your hosta (remove their food source): Seems like a lot of work but many times when gardens come under attack gardeners will do this. Many times I will plant the hosta in pots and then put them in the ground. If you take this approach ensure that you are putting the hosta in a cage or pot that will allow for growth. When I put pots in the ground, I will set them slightly below the surface and then put a perimeter of pebble stones on the surface. This way they can get water run off but you keep the voles out.
#2: Trap them: Yes, we are talking about killing them (sorry). This is one of the best ways to get rid of them. Put bait on the trap and then put the trap in an area where the voles are active, put the trap on the ground and cover with a big heavy pot. The voles will burrow from the bottom to get to the bait.