Moles are small, subterranean insectivores that feed primarily on earthworms, grubs, and other soil-dwelling insects. The visible mounds in a lawn are molehills, which are spoil dirt pushed up from complex underground tunnel networks. These networks include deep, permanent living tunnels and shallow, temporary feeding runs that create noticeable ridges. Lasting control requires addressing the mole within its active tunnel system, rather than just filling surface disturbances. The goal is to either repel the mole or physically remove the animal entirely.
Non-Lethal Tunnel Repellents
Repellents introduce an unpleasant taste or odor into the mole’s environment or food source, encouraging the animal to move elsewhere. The most common non-lethal substance is castor oil, often sold as a liquid spray or granular product. When applied, the oil coats the earthworms and insects that make up the mole’s diet, making them unpalatable.
Liquid castor oil repellents must be mixed with water and detergent, which acts as an emulsifier to help the oil penetrate the soil. This solution is applied to the affected area and thoroughly watered in with at least one inch of water to drive the oil deep into the tunnels. Granular products, which also contain castor oil, are spread over the ground and activated by watering.
It is recommended to treat the entire area rather than just a small patch, as moles will tunnel around perimeter treatments. Since effectiveness diminishes over time and after heavy rainfall, reapplication is necessary every few weeks. Although this method is non-toxic and safe for children and pets, it only deters the mole, and success is not guaranteed.
Chemical and Fumigation Options
For lethal control, two chemical options are available: toxic baits and fumigants, both requiring placement directly into active tunnels. Toxic baits now use synthetic worm or grub replicas to mimic the mole’s natural diet. These specialized baits often contain neurotoxins like bromethalin, which is lethal upon ingestion.
The synthetic baits must be carefully placed into the active runway, usually by poking a small hole and then sealing it with soil. This relies on the mole encountering and consuming the bait while traveling, which can be unreliable. Because these baits are highly toxic, they pose a significant risk of secondary poisoning to pets or non-target wildlife.
Fumigants, such as gas cartridges, release a toxic gas into the tunnel network when ignited and sealed. Restricted compounds like aluminum phosphide are only available to certified applicators. Fumigation is most effective when tunnels are deep and the soil is moist and heavy, allowing the gas to concentrate. Fumigants are often ineffective in porous or dry soils where the gas quickly dissipates through surface runs.
Strategic Placement of Traps
Trapping is widely considered the most reliable and effective method for eliminating moles. Success depends on identifying and precisely placing the trap in a main, active runway. To identify an active tunnel, flatten a small section of a surface runway. If the mole repairs the collapsed section within 12 to 24 hours, it is an active, frequently used runway and the ideal location for a trap.
There are three common types of traps: the harpoon, the scissor-jaw, and the choker-loop trap. The harpoon trap is set with the trigger pan resting directly on the depressed runway section. When the mole pushes up to repair the tunnel, the trigger releases, driving the spikes downward.
The scissor-jaw trap requires excavating a small section and repacking the soil underneath the trigger pan. The trap’s jaws straddle the runway, closing firmly across the mole’s path. Choker-loop traps are directional and typically require two to be set, one facing each direction, within an excavated section. All traps must be placed so the mole cannot detect light or air flow, which could cause it to divert its path.
Ineffective Methods and Safety Precautions
Many common home remedies for mole control are ineffective because they fail to address the mole’s biology or behavior. Flooding tunnels with a hose is usually unsuccessful because moles are capable swimmers and will simply move to higher ground. Placing foreign objects into the tunnels is also ineffective, as moles can easily dig around or push past them.
Ineffective Home Remedies
- Mothballs
- Chewing gum
- Pet waste
- Broken glass
Electronic or vibrating devices, often advertised to scare moles away with sound waves, have no scientific evidence supporting their effectiveness. Moles are adapted to the naturally noisy environment of the soil. Applying insecticides to eliminate food sources like grubs is also unreliable, since the mole’s diet consists primarily of earthworms, which are not affected by grub control products.
Safety Precautions
Always wear gloves when handling toxic baits or traps. Keep children and pets away from all treated or set areas to prevent accidental exposure. Never use flammable liquids like gasoline in tunnels, as this is extremely dangerous and contaminates the soil.