One of the most misunderstood pests around homes is the mole.  This creature is an insectivore.  Unlike other similar mammals such as mice which are omnivorous (eat a wide range of food types),  moles eat mostly grubs and earthworms below the soil surface.  It is the quest for food that results in the raised mounds and tunnels - the bane of many suburban homeowners. 

The three major moles pest species include the Eastern mole, the Townsend's mole (coastal Washington and Oregon states) and the Broad-Footed mole.  Eastern moles range in size from 5 to 8 inches in length and have closely cropped hair that is gray to silver in appearance.    The Townsend's mole is 8 to 9 inches in length and is blue-black to gray in color.  Finally, the Broad-Footed mole is also 5 to 8 inches but is brownish gray in color.

All three species have other distinct characteristics including an elongated snout, large padded feet with claws for digging and a short, nearly hairless tail. Their design is well suited to pursuing their food.


Moles create a series of horizontal and vertical runways.  The ones seen by people are shallow, horizontal runways which raise the soil under lawns or under plants and the short, vertical runways indicated by the volcano like mounds of soil.  (Gophers make similar mounds, but the soil is deposited into horseshoe or fan shape.) 

Deeper below the soil are the main runways which allow moles to travel quickly within their realm.  Soil removed from these areas is pushed to the surface by using the vertical runways and creates the mounds on the surface.


Grub control is frequently recommended for to help control moles.  However, it should be noted that since moles feed on organisms other than grubs, treating for grubs may not eliminate the problem.  The products of choice for grub control include carbaryl (Sevin) and triclorfon (Dylox).

There are harpoon type traps, baits and fumigants such as The Giant Destroyer are used for moles as well.  These products require a lot of time to set up because active tunnels must first be identified prior to their installation.

Here at The Bug Clinic, we recommend Whole Control and Mole-Out, two repellents containing 100% castor oil, an organically derived product.  Whole Control is the liquid version and is applied using a garden hose end sprayer.  This product is the more economical of the two and is best suited to treating large areas.  Additional water is used to wash the castor oil below the soil surface.

For smaller or garden areas, Mole-Out the granular companion to Whole Control, may be applied and then watered in.  As with Whole Control, a copious amount of water is needed to wash the active ingredient below the soil.

The concept of using castor oil is that while harmless to the environment and non-target organisms, it contaminates the mole's food causing it intestinal distress.  This discourages the mole from feeding in those areas and they will move on to seek food elsewhere.

Note that castor oil is a repellent which remains effective for up to three months.  If moles return after that time,  quarterly applications of one of the two products may necessary.  Application of a grub control along with one of the castor oil products is recommended.

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