Holy moly: Pests or pest killers?

Peter Warren, Virginia Cooperative Extension

Q: What can I do about moles digging up my yard? Is this a good time to get rid of them?

 A: First, a little bit about moles. Moles are solitary creatures that live underground and feed on earthworms, snails, slugs, and insects. Moles destroy very few plants or bulbs by direct feeding, but they may dislodge plants while tunneling in search of food.

When you think of moles and their insect-eating ways, you may decide they are good to have around, since some of the insects they eat, such as Japanese beetles, are damaging plants. Additionally, their tunneling aerates the soil and mixes in organic matter, enhancing soil quality.

If gardeners still want them out after considering these facts, there are a few methods available. If the area of concern is small, one solution is to dig a trench around the area and install a barrier of hardware cloth or sheet metal. The barrier should extend about five inches above the ground surface and 8-10 inches below with the bottom end bent into an "L" shape extending away from the bed.

For larger areas, traps are a possibility. The best time to do this is in the spring when the first ridges– indicating mole tunnels– are noticed. Trapping moles requires constructing a "pit trap" into which the moles can fall and not escape as well as knowledge of which tunnels are active so you know where to place the trap. Usually, keeping an eye out for freshly raised sections of tunnel is sufficient.

Stomp the tunnels with your foot, and see which ones are raised again to know if they are active. It is not legal to relocate moles off your property without a permit. Other ways of dealing with captured moles are relocation to less objectionable areas of your own property or euthanasia. A veterinarian can help with this if needed. I do not recommend "kill traps" because they can be dangerous to set and potentially harmful to children and pets.

There are repellents labeled for moles like the ones offered for other animals. These are often effective only for a short time, if at all. Insecticides that target their food sources are not very effective because moles eat a variety of invertebrates and should not have trouble finding more food.

Other things that do not work at all are sonic or vibration producing devices and various home remedies such as gassing with auto exhaust, placing broken glass, pins, or other sharp objects in the tunnels, and use of harsh household chemicals. Not only are these methods ineffective, but they can be hazardous to residents, non-target animals, and they may be illegal.

People who are experiencing significant plant damage associated with tunnels may have voles– also known as meadow mice– instead of or in addition to moles. They are sometimes confused because voles may move into mole tunnels to access plants.