How to deal with tunneling pests in your yard

Photo of Mole

The days are getting warmer, which means destructive, furry varmints are busy tearing up lawns and damaging plants.

It’s time once again for moles and voles to go after your lawn and garden.

“A mole will generally remain underground and not come to the surface, but most people are familiar with the damage they do with their feeding tunnels and the molehills that they make,” said Brad Fresenburg, assistant professor of plant sciences for University of Missouri Extension.

“Most homeowners will notice a network of tunnels that have these inch-and-a-half to 2-inch diameter holes where they can enter and exit,” he said.

Voles are much smaller than moles. Another difference is that moles are carnivores, eating mostly earthworms and grubs, while voles are herbivores.

“In my mind, voles can be even more destructive to plants and ornamental beds and flower beds because they do feed on ornamental bark, flower bulbs, roots and such,” Fresenburg said.

Even though moles don’t damage plants, their raised tunnels and unsightly mole hills can be a source of frustration for homeowners. Trapping is probably the most economical control method, he said.

The key to trapping success is finding an active tunnel.

“Moles feed and rest on a two-hour cycle, 24 hours a day. By poking holes into the top of tunnels, the mole will come back and plug up those holes in an active runway. That’s where you set your trap,” Fresenburg said.

There are harpoon traps, choker types and scissor traps available. Fresenburg says some of the newer scissor traps are easy to set. You place the scissors into a feeding runway, then use your body weight to set and lock the trap in place by stepping on top of it.

Harpoon traps are relatively inexpensive and can be found at most garden centers, he says.

“Once you locate an active runway, take your foot and push down the tunnel where you want to set the trap. Insert it completely into the soil, moving it around a little bit and up and down to make sure that when the trap is sprung there isn’t anything that’s going to hold back the harpoon,” Fresenburg said. “Then once you set the trap, make sure that the trip plate is just above the soil surface and the trap should spring without any hang-ups.”

There are mole repellents made with castor oil. Moles don’t like the smell, so it does repel, but the smell doesn’t last long. You’ll need to reapply castor oil repellent throughout the spring, summer and fall for it to remain effective, Fresenburg said.

There are also worm- and grub-shaped baits that can be applied into an active runway. “They’re flavored with attractants and contain a rodenticide, bromethalin, that is very effective,” he said.

Controlling voles requires a different approach. Voles tend to live in colonies, so getting rid of one or two won’t help much.

“You’d probably need to bait five or six within a colony before you notice a difference,” Fresenburg said.

To control voles, find the entrance and exit holes and place poison baits in those holes.

“If you notice that they have some feed runways on the surface, then regular mouse traps or a bait station can be used.”