Controlling Moles in Lawngrasses

Moles are about the size of a small field rat. Their average length is 5½ - 6 inches with a short sparsely haired tail. They have very powerful front feet designed to push soil out of the way for their tunneling. They also have a gray fur that actually points up to allow them to move forward or backward in the tunnel without getting soil in their coat.

Moles prefer loose, well-drained soils.The familiar tunnels are created as the mole searches among the plant roots for the earthworms and insects on which it feeds. Moles are beneficial because they eat mole crickets; beetle larvae (white grubs, wire worms, etc.); ants and ant brood; moth larvae and pupae (cutworms and armyworms); and slugs. They also help to loosen and aerate the soil. In loose soil, moles can tunnel up to 18ft per hour. Their living space is in tunnels and chambers 6-12in below the surface. Soil from these deep burrows is pushed to the surface in small mounds.

The mole's nest chamber is 4-6in in diameter and lined with fine grass and leaves. Moles have one litter of 2-5 young per year. The young are born in March after a 45-day gestation period. They are large at birth relative to the size of their mother and are able to fend for themselves in about four weeks.

Although moles are often falsely accused of eating the roots of grass and other plants, they actually feed on the insects causing the damage. The tunneling of moles may cause some physical damage to the root systems of ornamental or garden plants and may kill grass by drying out the roots.

Moles can be live trapped using a simple pitfall trap. To do so, collapse a tunnel with your foot, then come back in an hour or two to see whether the tunnel has been reopened. If the tunnel has been pushed back up, it is an active tunnel. Dig a hole through the tunnel large enough to insert a large coffee can, wide-mouth quart jar, or similar container. Sink the can into the ground so the top of the container lies just below the bottom edge of the tunnel.

Cover the area with a piece of cardboard or a board and the soil from the hole to keep light and air currents from alerting the mole to the trap. When the mole falls into the trap, the whole container can be pulled out of the ground and carried to a forested area and released.

Commercial mole traps are available in two main types: the choker-loop and the harpoon. The harpoon trap impales the mole with steel spikes when the animal pushes up on the trigger. To improve soil penetration, the spikes should be worked into the soil prior to setting the trap. Step on the tunnel to partially collapse it and set the trap so the trigger is over the collapsed section of tunnel. A plastic bucket can be placed upside down over the trap to keep children and pets from disturbing the trap. After 3 days move the trap if not sprung.

Barriers can also be made with small-mesh galvanized hardware cloth, brick, or concrete. The barrier should extend at least 6in above the ground and 2ft below the ground, with an outward projection extending 3-6in.

Moles can be discouraged from digging foraging tunnels in turf by controlling the population of insects on which they feed. Elimination of white grubs, mole crickets, and other soil insects will make an area less attractive to moles. Identify the insect pests so the appropriate control method can be used.

Several mole repellents are available that use emulsified castor oil to repel moles from treated areas. The duration of effectiveness of these products is related to soil type and the amount of rainfall. They remain effective longer in clay and loam soils than in sandy soils. During rainy periods, these products may need to be applied more often.

The use of vibrating devices to drive away moles has not been proven effective in scientific trials. In fact, the presence of mole tunnels next to highways would seem to be evidence against the effectiveness of these devices. The same is true for the use of mothballs to repel moles. The mole just blocks off the treated tunnels and moves to a different part of the yard.

Flooding the tunnels with water may force moles to the surface , but this method rarely works in our sandy soils. For more information on moles, a UF/IFAS publication is available at http://edis.ifas.ufl.edu/UW080.

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