The presence of moles in turfgrass is a common challenge for homeowners, characterized by extensive tunneling that damages the appearance and health of the lawn. These small, insectivorous mammals create complex underground networks in their constant search for food, primarily earthworms and insect larvae. Understanding the specific signs of mole activity and applying targeted removal and prevention strategies are necessary steps for restoring a smooth, healthy lawn. Effective management requires a systematic approach, moving from positive identification to control methods and finally to long-term habitat modification.
Confirming Mole Activity
Confirming the pest is a mole is necessary, as their damage can sometimes be confused with that of voles or gophers. Moles create two distinct types of surface signs: the molehill and the raised runway. Molehills are volcano-shaped mounds of loose soil, created when the animal excavates deeper tunnels and pushes the dirt vertically to the surface. These mounds are typically round and do not have a visible open entrance hole in the center.
The raised runway is a visible ridge of lifted turf across the lawn surface, indicating a shallow feeding tunnel just beneath the grass roots. If you press down on a runway and it feels spongy or collapses easily, it is a sign of mole presence. In contrast, gopher mounds are often crescent or fan-shaped with a plugged entrance hole off to one side, while voles typically create small, open burrow holes and visible surface pathways through the grass.
Direct Physical Removal Methods
Trapping is the most effective, immediate method for eliminating moles from a lawn. Success depends on setting the trap in an active main runway, which are the deeper, more permanent tunnels moles use for travel. To identify an active runway, flatten a section of a raised tunnel and check it after 12 to 24 hours; if the tunnel is pushed back up, it is active and a prime location for a trap.
Several types of traps are available, including the harpoon trap, the scissor trap, and the choker loop trap. The harpoon trap is set over a shallow runway, while scissor traps are inserted directly into the tunnel after excavation. Choker loop traps use a wire loop to snare the mole as it passes. Proper placement involves digging a small opening into the active tunnel, setting the trap according to instructions, and then covering the opening to block light and airflow, which encourages the mole to use the tunnel and trigger the device.
Chemical and Toxic Bait Options
Commercially available mole baits are often formulated to resemble the mole’s primary food sources, earthworms and grubs, frequently molded into the shape of a worm. One common active ingredient is Bromethalin, a neurotoxin that can be lethal to the mole within 24 to 48 hours of a single feeding.
These baits must be carefully placed directly into active mole tunnels using a probe to avoid surface contamination and reduce the risk to non-target animals. Another substance sometimes used is Zinc Phosphide, which releases a toxic phosphine gas when it reacts with stomach acids. Due to the high toxicity of these ingredients, strict adherence to safety precautions, including wearing gloves and preventing access by children and pets, is necessary.
A more indirect chemical method involves using broad-spectrum insecticides to significantly reduce the population of grubs and earthworms. This removes the mole’s primary food source, encouraging them to move away.
Long-Term Deterrence and Prevention
Long-term management involves modifying the lawn environment to make it less appealing to moles, encouraging them to relocate. One common non-lethal repellent is castor oil, available in liquid and granular forms. When applied and watered into the soil, the castor oil creates an unpleasant taste and odor that moles find irritating, prompting them to leave the treated area.
Some homeowners also employ sonic or vibrating devices, which are placed in the ground and emit periodic vibrations intended to disrupt the mole’s sensitive underground environment. While the efficacy of these devices is inconsistent, they offer a non-chemical deterrent.
Cultural practices are also beneficial, such as managing soil moisture; excessive watering softens the soil, making tunneling easier and attracting more earthworms. Maintaining a drier lawn can help discourage activity. Installing an underground barrier of hardware cloth or mesh, buried at least 24 to 30 inches deep around high-value areas, can provide a physical exclusion against new incursions.