Nothing is more frustrating than spending your free time trying to cultivate a healthy garden, only to have it overrun with underground pests. In this article we discuss what to do about moles.

Poisons are usually the first method that a homeowner thinks of, but is not necessarily the best choice. Poisoned gummy worms or pellets with bromethalin may be inserted in an active tunnel, but they may pose a hazard to humans and pets and may possibly enter the wildlife food chain. If poison baits are left in place, they have the potential of being washed into water sources. When using any type of poison or chemical, carefully read and follow the label instructions.

The most effective control for moles is to cut off the food supply. Using a grub treatment for a lawn is a common practice. Systemic grub treatments that contain imidacloprid as an active ingredient can be applied to the lawn area in May. These are available in ready-to-spray, hose-end sprayers or granular formulations. Granular products are easier to apply, but be sure to irrigate with at least ½ inch of water immediately after application. Because these products are systemic within the turfgrass, they will last the entire growing season. Granular grub killers that contain trichlorfon or carbaryl are contact insecticides that should be applied in early July and are spread over the lawn and watered in well. At this time, the grubs are small and close to the surface, so the contact insecticide will be very effective in eradicating the young grubs. This will last for about two weeks. Application in the late summer or fall is not as effective, as the older grubs will go deeper in the soil and are harder to kill. Neither of these methods are completely successful, as the moles will switch to other prey, such as earthworms and other insects.

As a more environmentally friendly but temporary solution to a mole infestation, consider an application of castor oil to the lawn. It is available as a spray or in a granular form and will repel moles and voles for about two weeks.