Mole control without myths

Controlling moles without myths

Controlling moles is not impossible once you learn the correct way to do it, even though it may not be the easy job some folk remedies promise.  There are hundreds of folk remedies for controlling moles and sometimes they seem to work.   That’s because the moles moved on to better hunting grounds or went deeper into the ground on their own, not because of the folk remedy.  When you learn about mole biology and behavior it’s easy to understand why some remedies are useless.

There are two species of moles in the upper Midwest, and several other species across the US.  The most common moles are  are the Eastern Mole ( Scalopus aquaticus) and the Star-nosed mole   (condylura cristata).  If you are examining an animal you think might be a mole here’s what to look for.

Moles have short, plush coats of light gray to dark brown. There are no visible ears, the eyes are very small and hard to find.  Moles eyes are only able to distinguish light from dark.  The nose is long and pointed and bare at the tip.  The Star-nosed mole has a distinguishing feature of 22 fleshy tentacles around the nose that give the mole its name.  Moles have tiny, very sharp teeth with no big flat incisors in the front like rodents.  The moles front feet are broad and paddle like, with webbed, thick toes.  The soles are generally visible. The hind legs and feet are small and less developed.  The moles tail is shorter than the body.   The Star-nosed mole has a fat, lightly haired tail.  The Eastern mole has a thinner, bare tail.  An adult mole is about 4-6 inches long.

The Star-nosed mole prefers to live where the water table is high, and next to marshes and ponds.  It is partly aquatic and along with earthworms eats thing like water beetles, snails, small crustaceans and even small fish.  It is sometimes seen swimming in shallow water.   The Eastern mole is an insectivore/ carnivore and prefers drier locations.   Contrary to popular belief its diet is not primarily grubs but earthworms and a wide variety of other critters that live in the ground.  If you have grubs in your soil a mole will gladly eat them, but grubs do not have to be present for moles to be present.   The diet  of both moles is at least 98% animal based. 

Moles do not eat the roots or bulbs of plants nor do they eat fruits or plant parts above ground.  Their teeth are not made for eating roots and other tough vegetation.  Some roots may be damaged by tunneling.  If you have bulbs and things like potatoes being eaten you probably have voles, mice, rats, chipmunks or ground squirrels.  Sometimes these critters follow mole tunnels but sometimes they make their own. 

Most mole tunnels are soft and collapse easily. The damage is most apparent in spring when moles feed close to the surface and vegetation hasn’t grown enough to hide the raised tunnels and mounds.  Moles dig tunnels to look for food and to live in.  The home tunnels are usually straight, deeper in the soil and along a natural or human boundary such as a line of shrubs or trees, or a foundation or pavement. The home tunnels are used daily.  The mole retreats there to sleep or care for young.  Nests of dried grasses and leaves can be found in these tunnels.

Food hunting tunnels can be deep or at the surface of the soil, where they bring the attention and wrath of humans.  On the surface of the soil these tunnels appear as raised mounds that may zig and zag through the garden or lawn.  These are dug to hunt for prey, which falls into the tunnel as the moles dig and is gobbled up.  Most hunting tunnels are used only once, at least by the mole itself.  There are connecting tunnels between hunting tunnels and home tunnels that may or may not be used more than once. 

There are also mounds of soil made in gardens and lawns where excess soil is pushed up out of the tunnels.  These are more common with Star-nosed moles but Eastern moles also make them.  The mole mounds do not have open holes, when the mole is finished pushing up the soil it plugs the hole.  When other animals take over mole tunnels these holes may be re-opened and a visible opening is seen in the mound.

Moles do not undermine pavement or foundations.  If you have that kind of damage you may have groundhogs or rats.  Star-nosed moles may contribute to erosion of banks by water edges with their tunnels.

Moles are fiercely territorial and solitary animals except at breeding time.  It is believed that Star-nosed moles may pair up through winter but go solitary after breeding in the spring.  There are never hundreds of moles in your yard, or even dozens even though it may seem that way.  At the most a suburban lot will have space for 2 moles, except for a short time when babies are with the mother.  An acre might support  6-10 moles.  But if you kill one mole another may quickly take over that territory, which makes it seem like there are a lot of moles.

What doesn’t work- the myths

Castor oil is often said to kill or repel moles.  Moles, like most creatures, do not like the taste or smell of this very toxic product.  At least one company makes a commercial mole “remover” using castor oil.  However a study done by Michigan State University , which is often used as proof that castor oil works ( a product that contained it) to get rid of moles, was very small, criticized by peer review for not being very well constructed or controlled and has never been replicated by any other study.  There is no reliable scientific proof castor oil products repel or kill moles.

Even with a popular dish detergent added the castor oil mix doesn’t  penetrate the ground very far and worms and other insects will move away from it if they can. The smell will shortly disappear.  Spraying it on the surface won’t do anything; it would have to be applied in large quantities in a strong, undiluted concentration and allowed to soak in. Folk remedy concoctions don’t have the amount or concentration of castor oil to do anything.  Moles will go deeper into the ground, and then reappear when the product dissipates.

Just because you took or were given castor oil as a child does not make it a safe product. You were being given a sub-lethal dose of a poison. Castor oil can kill non-target species  and if you have pets or kids these product could be picked up on feet or hands and make them very sick.  New granular castor oil products should be avoided because of this.  Moles would not eat anything that smelled like castor oil, and they don’t eat anything that doesn’t smell and feel like their normal prey.

The planting of castor bean plants in areas where there are moles could possibly deter them, if the whole area was planted to castor beans, which are extremely poisonous.  But that means no more lawn or garden anyway.  But a border of the plants doesn’t work because moles can tunnel deeply under those plants without a problem.  The same thing is true of mole plant (Euphorbia latharis), you would have to plant the whole area, not just a border, if it had any effect at all, which there is no proof that it does.

What if you treat the lawn for grubs?  Grubs aren’t the only food that moles eat; in fact the basic food for moles in most places is earthworms.  Grub control usually doesn’t kill worms, although it depends on what pesticide you use.  Grub control is expensive, and can harm beneficial insects, birds and pets.  If your lawn has no grubs it can still have moles.  Check for grubs before you apply grub control products.  Treating lawns and gardens with broad spectrum pesticides that kill everything is a really unsafe and environmentally destructive practice. 

Putting gum into mole tunnels won’t work, whether it’s chewed or not and regardless of brand or flavor.  Moles won’t eat gum.  They only eat worms and insects.  They just tunnel right over it. And if gum doesn’t kill you why would it kill a mole if it did eat it?

Moles also won’t eat cornmeal, grits or anything else with the idea that it will expand in their gut and kill them.  They won’t eat mouse or rat poisons, even if put into their tunnels.  These things are not attractive to moles.

What about poison gas?  People have all sorts of stories about hooking up car exhaust to tunnels and gas canisters are sold with elaborate instructions.  But these things don’t work well because the mole tunnel systems are usually extensive and disperse the gas, and soil also absorbs much of the gas.  Moles are adapted to surviving in high carbon dioxide/low oxygen atmospheres underground.   Flooding a tunnel with water might work to kill babies in a home tunnel, but mole tunnels are built to handle draining away water, soil absorbs a lot of water, and moles can move away from water or even swim away without a problem.

Putting broken glass or razor blades in mole tunnels won’t hurt them – at least it won’t kill them and is more likely to hurt you or someone else who digs in that area in the future.  Think about it- they would just cover these materials or go around them. Used kitty litter, various urine concoctions, essential oils, fabric softener sheets all have the same failing.  They don’t last long and moles can simply avoid them.  Moles don’t even go back to most of their tunnels a second time.

Then there are the windmills, and wine bottles and such sunk into the soil that are supposed to vibrate and scare away moles.  Moles are exposed to vibrations all the time around humans.  Cars, farm machinery, people and animals walking by, loud music, vibrations abound.  Moles detect large predators from vibrations but they get used to constant vibrations and can differentiate harmful from harmless vibrations .  And ultrasonic devices do not work on any pests, there’s no scientific research that has supported that, and ultrasound wouldn’t penetrate the soil very far anyway.

What really works to get rid of moles

So what does work?  There really aren’t any good repellents, despite many claims based on anecdotes.  If you want to get rid of moles you need to kill them.   A good cat or dog will kill many moles, although they rarely eat them.  Dogs will do a lot of damage following a mole tunnel and digging it up.  Since moles mark the tunnels as they move through them to deter other moles, a dog will often dig up a tunnel for a long way because he smells the mole.  Cats usually wait to see movement just under the ground before they dig to get the mole. If you tolerate snakes many will clear an area of moles in no time.

People can be mole killers too.  Sit in an area very quietly where there is lots of mole activity and wait to see one moving under the soil.  Shoot it with a bb or pellet gun or plunge a shovel or pitchfork into it.  Some people throw them up on the ground with a shovel and dispatch them.

Traps are very effective once you learn how to set them and where.  You need to practice and with practice you’ll get good at placing and setting traps.  The trap must be specific for moles.  Follow the directions for setting the traps carefully.  Traps must be placed in home tunnels, tunnels that are re-used.  You find these by tramping down tunnels and seeing which are repaired in 24 hours.  If they get repaired they are a good place to set a trap.

New poison baits are on the market that are shaped and scented as either worms or grubs.  Moles do eat these gel poisons and they are fairly effective, although not as effective as traps.  (Note: candy jelly worms do not work! It has to smell like a worm and contain poison. ) Brand names include Tomcat Mole Killer (Talpirid) and Bonide's Moletox Baited Gel, a water-based gel containing warfarin.  A few other poisons shaped and scented like worms also exist.   These must be placed in active tunnels.  The products are expensive and they must be kept away from children and pets.

Moles are by and large beneficial to the environment.  They control many pest insects by eating the larval stage in the soil.  They aerate and mix soil layers.  And they provide homes for other beneficial creatures such as snakes and toads.

Some people learn to tolerate the cosmetic damage caused by moles in early spring, knowing that much of it will soon disappear.  There are booms and busts in mole populations, usually following the booms and bust cycles of insects such cicadas, which have a larval stage in the soil.  Some years a mole population will be higher than others.  If you wish to control moles though, follow a good research based method that really works instead of wasting your time and money on folk based remedies that don’t work. Please don’t pass on folk remedies that have no factual basis and ignore basic science about mole behavior.