Biology & Ecology
Moles are small mammals that spend most of their lives underground. If it were not for their tunnels and mounds of pushed-up earth, they would go unnoticed. A typical mole population density is two per acre. Moles often make their tunnels when the soil is damp. Using their enlarged, spade-like front feet and heavily developed muscles and skeleton, the common mole can dig 15 feet of tunnel near the surface in an hour. Moles dig two types of tunnels: Feeding tunnels that are just under the surface and permanent tunnels (nests) that are below the frost line (10 to 18 inches below ground level). Moles dig tunnels in lawns to feed on insect larvae and earthworms. Although moles do eat some plant roots, over 80% of their diet is worms and insect larvae. The common mole may eat half of its body weight each day.
In Virginia, the common mole (Scalopus aquaticus) is most abundant. Length is up to 9 inches including the almost naked tail. Mole fur is plush, and gray or brown. Moles mate in Spring and 4 to 6 weeks afterward, 2 to 5 hairless pups are born in an underground nest. After one month, the young can fend for themselves. Moles are largely solitary, except during mating season.
Controlling Mole Damage
Homeowners with mole problems are willing to try just about anything to control them. Typical control methods involve insect control, poison baits, or ultrasonic noise makers, and less conventional methods involve lying in wait with a BB gun.
First let’s address insect control. A common misconception is that white grub control will eliminate mole problems. While moles do eat white grubs as well as many other insect larva, their diet consists primarily of earthworms (which are beneficial to the lawn). Controlling actively feeding grubs in the late summer and early fall may help in moving moles to an adjacent lawn but most homeowners detect mole damage in the spring or winter. This is not an effective time to apply grub control because grubs do not feed at this time. This is when the ground is soft and moist and the worms tend to gravitate to the surface. Have you noticed after a rain the amount of earthworms on your driveway and sidewalk? The moles are drawn to where the food is, at the surface. This is why the tunnels are more visible.
Trapping is the recommended method of control. Harpoon and choker style traps are sold for mole eradication. Both traps kill moles quickly. The key to successful trapping is to set the trap on a main feeding tunnel. Some mole feeding tunnels are used as main travel runs, but most mole feeding tunnels may only be used once. Locate main travel tunnels by stamping down all tunnels in the lawn. By the next day they will push up the soil blocking their main travel tunnels. Stamp down the tunnel again and set the trap. If a mole is not trapped in three days and new tunnels appear in the lawn, repeat the process. Trap until there are no new tunnels produced.