The presence of subterranean pests like gophers and moles can quickly transform a landscape into a minefield of mounds and damaged roots. These burrowing mammals create extensive tunnel systems that compromise turf health and destroy garden plantings. Successfully removing these pests and preventing future damage requires a tailored approach, as the methods for controlling gophers are distinctly different from those used for moles. Understanding the habits and identifying signs of each animal is the first step toward reclaiming your yard.
Identifying Your Pest: Gopher vs. Mole
Differentiating between a gopher and a mole is crucial because their diets and tunnel structures demand separate control strategies. Gophers are herbivores, primarily feeding on plant roots, tubers, and the occasional above-ground vegetation they pull into their tunnels. Conversely, moles are insectivores, with their diet consisting mainly of earthworms, grubs, and other soil-dwelling invertebrates. While moles do not intentionally eat plant material, their tunneling can still sever roots.
The mounds of soil they create offer the most visible clue for identification. A gopher mound is typically fan-shaped or horseshoe-shaped, with the soil plug located off to one side. Mole mounds, often called molehills, are generally more circular or volcano-shaped, with the plug situated in the center of the pile. Moles also create simple raised ridges on the surface of the lawn, which are shallow feeding tunnels, while gopher tunnels are deeper and lack these distinct surface ridges.
Preventing Entry with Physical Barriers
One reliable long-term strategy for protecting specific areas, such as garden beds or small lawns, involves installing physical barriers. These barriers prevent the pests from gaining access to the protected zone from underground. Galvanized hardware cloth or wire mesh with a half-inch opening size is the preferred material, offering durable protection against both gophers and moles.
For perimeter exclusion, a trench should be dug around the area intended for protection, ideally 18 to 24 inches deep. The mesh should be placed vertically, extending a few inches above the soil line to deter above-ground entry attempts. A key design element involves bending the bottom of the mesh outward at a 90-degree angle to create an L-shaped barrier. This outward flange of 4 to 6 inches prevents the pests from burrowing straight down along the barrier’s edge to bypass it.
For new sod or grass installations, a horizontal layer of hardware cloth can be laid just beneath the surface to prevent damage from below. The mesh should be covered with at least one to two inches of soil before the sod is placed. This prevents the animals from pulling grass through the openings or pushing soil up. While labor-intensive, this exclusion method offers a non-toxic, permanent solution for safeguarding valuable plantings and turf.
Using Repellents and Non-Lethal Deterrents
Repellents work by creating an undesirable environment that encourages the pests to relocate, offering a non-lethal control option. Castor oil-based products are effective, particularly against moles, as they are insectivores that rely on their sense of smell to locate food. When applied, the oil coats the soil and the invertebrates within it, causing digestive upset or rendering the food source unappetizing to the mole.
Liquid castor oil concentrates are mixed with water and a small amount of dish soap to help emulsify the oil and improve soil penetration. This solution must be thoroughly watered into the ground to ensure it reaches the mole’s active tunnels. A second application is often recommended after heavy rain. Granular castor oil products are also available, though they may be less effective than liquid formulations because they do not penetrate the soil as deeply.
Another deterrent includes vibration or sonic-emitting devices inserted into the ground. These devices create a continuous disturbance in the soil, which is theorized to be annoying to subterranean animals. However, the effectiveness of sonic spikes is limited, as the vibrations may only cause the pests to temporarily shift their tunneling activity to an adjacent, untreated area. For best results, treat the area in stages, pushing the pests toward a desired exit point off the property.
Effective Trapping and Eradication Strategies
Trapping remains the most immediate and successful method for eradicating gophers and moles. The approach differs based on the species, requiring specific trap types and placement techniques. For gophers, effective traps include specialized devices like box traps, scissor traps, or choker-style traps, which are placed directly into the main tunnel runs.
To locate the main tunnel, use a probe rod near a fresh, plugged gopher mound, searching for the sudden drop indicating an open runway. Traps should always be set in pairs facing opposite directions within the main tunnel, ensuring the gopher is caught regardless of approach direction. Gophers are sensitive to light and airflow, so the trap setting must be covered with soil or sod to make the tunnel dark. This encourages the animal to approach and plug the opening, triggering the trap.
Mole trapping focuses on eliminating the animal within its active surface runways, which are the raised ridges or feeding tunnels. Harpoon-style or scissor-jaw traps are the common tools, designed to be triggered by the mole pushing up soil as it repairs a collapsed runway. Unlike gophers, moles are rarely baited since they are primarily carnivores. The trap must be placed directly over an active run and set with precision. Traps for both pests should be checked frequently, and safety precautions must be taken to prevent accidental contact by children or pets.