Issue 7, July 13, 2020

Controlling Moles in Turf

We may never actually see a mole, but we sure know when we have one in our yard.  A person will notice mounds of soil (molehill) and surface tunnels in the lawn, as these are good indicators that moles are around. Moles live most of their lives underground. They are built for an underground lifestyle with very small eyes that are sealed by fused eyelids, allowing them only to distinguish between light and dark. Their ear canals are concealed in fur with no external ear. The forefeet are long and broad, with palms wider than they are long. The toes are webbed at the base of their claws. The hind feet are small and narrow with claws. The snout is light pink colored and nearly hairless.  Their average length is approximately 7 inches with dense grey or brownish color fur.  The hands and feet make it very easy for them to push and move dirt as they are searching for food.  In Illinois, we typically deal with the Eastern Mole. 

Moles can be destructive pests in lawns, gardens, golf courses and parks.  Mounds of loose soil are indicative of a deep tunnel. These cone-shaped mounds are usually four to six inches high and about one foot in diameter. They are usually present in pairs, with each mound being six to twelve feet apart. Beneath each mound is a vertical tunnel that extends five to eight inches below the surface to a horizontal tunnel. Tunnels that are deeper within the soil do not result in a ridge on the soil surface. The horizontal tunnel runs to the vertical tunnel beneath the adjacent mound.

Deep tunnels are used by the moles for bearing and rearing young. Thus, the presence of mounds usually indicates the presence of a reproducing pair of moles.

Figure 1Turfgrass injury resulting from mole

Life Cycle

Moles are omnivores and live a relatively independent lifestyle. There is typically no more than 2-3 moles per acre. They can dig 1 foot per minute. Their day is spent feeding and resting on two-hour cycles, 24 hours a day. Moles eat earthworms, grubs, millipedes, centipedes, spiders, sowbugs, snails, and slugs. They may also feed on seed and vegetable matter.  Since they are eating basically around the clock, they can consume 70-80% of their body weight a day.

Mating occurs in the late winter, and gestation lasts 42 days with a single annual litter of 2-5 young being produced between March-May. Young are born only once per year, and the young stay with their mother through the summer. Those that near maturity in late summer or early fall due to an early litter are pushed from the d

It is these adolescent moles striking out on their own that typically venture into lawns and other maintained turf areas. Damage to turf is usually seen in spring and again in fall based on when they are driven from their mothers' range.

Management

Management is difficult. It is a common misnomer that if you have grubs, you have moles. Moles are insectivores, meaning they eat insects, worms, and other invertebrates. Grubs are just a portion of their diet. So even putting on grub control will not effectively eliminate moles. Some methods for control and damage prevention are exclusion.  This includes things like using repellents, packing the soil, toxicants, fumigants, and trapping. Some ways to reduce the habitat's attractiveness include reducing the soil moisture, use insecticides to reduce the food supply and trap.

A practical method for mole control is with harpoon or choker traps set across straight tunnels that intersect with other tunnels. The tunnel should be mashed down or use a broom handle to poke holes in the runs.  Check the holes or mashed down tunnels to see if holes have been replugged or tunnels pushed back up. This means this is an active feeding tunnel. Set a trap in that area.  As the mole comes down the tunnel, it tries to rebuild the destroyed tunnel springing the trap, killing the mole. In heavy soils, it is useful to spring the trap once or twice to create openings where the harpoon or jaws can travel.

Bromethalin, sold as Talprid, is also available for mole control. The pesticide is sold in a plastic worm. A hole is made in the top of a straight tunnel, the "worm" is dropped into the tunnel, and the hole is repaired. This limits the exposure to pets and other non-target animals. Always wear latex gloves when handling traps and bait to avoid human scent contamination.

Resources

http://hyg.ipm.illinois.edu/article.php?id=112
https://www.canr.msu.edu/news/moles_in_the_lawn
https://content.ces.ncsu.edu/moles-in-turf
https://ipm.missouri.edu/MEG/2012/3/How-to-control-moles-and-reduce-turfgrass-damage/

Adapted from an article by Phil Nixon

Author:
Maria Turner

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