It is truly amazing that such a small
creature can be the focus of so much interest, anger and even hatred.
For some lawn caretakers, moles can be their arch nemesis, seeming to
challenge them for control of the yard. Part of their mystique is that
moles are mysterious rodents that live in the soil and are rarely seen
on the surface. While they can certainly cause an appreciable amount of
damage to a lawn, they often take the blame for damage they didn't
cause. And moles are rarely given any credit for the good work they do.
About the Moles
The most common type of mole in our
urban area is the eastern mole. In more wooded, wetter areas, we
occasionally find star nosed moles. Moles are about 6 inches long,
grayish-brown in color, tail-less, have an extremely short, pointed
snout and paddle-like front feet. There are a lot of misconceptions
about what moles eat. All moles are basically insectivores. They are
burrowing around in the soil looking for grubs, wireworms, beetles,
ants, insect larvae, earthworms and such. They rarely eat plants,
bulbs, roots or other vegetable matter. Moles have an extremely high
metabolism and a voracious appetite that keeps them moving almost
constantly in search of food. They are incredible excavators that often
tunnel 12 to 15 feet every hour. While digging, they can hear and smell
their food. Moles have a few deep tunnels that lead to a burrow but
those aren't the tunnels that bother gardeners. It is their shallower,
foraging tunnels that cause problems. Moles are fairly solitary
creatures and you will seldom find more than one or two in a yard.
Their Impact on the
Landscape
The tunnels they make when looking for
food are within a few inches of the surface of the soil and cause
raised ridges on the lawn. If the tunnel isn't too close to the
surface, you may not see the ridges but you will find the soft runs
when when you walk across the lawn. Most of this activity takes place
in open grassy areas where the moles don't have to work around tree
roots, but they will wander into a garden or flower bed too. Their only
serious impact in the landscape is the unevenness they cause on the
surface. They don't actually harm anything else. And, as much as we
don't want to acknowledge it, they help control quite a few harmful
insects and help relieve soil compaction.
Methods of Control
For many gardeners, the ridges and
tunnels created by moles are serious enough to warrant taking some sort
of action. Other than learning to live with them, there are several
ways to deal with moles. For our purposes, we will divide mole control
methods into those that are practical and proven and those that are not
safe, impractical or unproved. Whatever methods you decide to use, keep
in mind that moles are most active and closest to the surface in spring
and early summer or during wet periods. They also breed in the spring,
so trying to control them early will help limit the future population
too.
Mole Control Options
Practical and Proven
Trapping
There are several types of effective
traps that have been marketed for years. Because of the nature of the
mole, live traps are not very workable. All those that work kill the
mole. Traps are available at most hardware stores and directions for
setting them should be followed carefully.
Repellents
Another approach is to repel the mole
from your landscape. Recent research done in Michigan has proven that
moles are repelled by the scent of castor oil. There are now products
made from castor oil on the market that can be sprayed on the lawn.
When the diluted oil soaks into the soil, moles avoid those areas.
Effectiveness will vary with the type of soil and timing of the
application.
Minimizing Food Source
Many of the insects that are prime
food sources for moles can be minimized by using beneficial nematodes.
These are actually microscopic worms that target grubs and many other
insect larvae in the soil without harming beneficial soil dwellers such
as earthworms. To work, the soil needs to stay moist. Beneficial
nematodes can be purchased at some garden centers early in the growing
season or mail ordered. They are living organisms and have to be
handled carefully. Once the soil is inoculated, the nematodes can
reproduce quickly, controlling soil larvae all season long. They should
be reapplied yearly. There is another biological control called milky
spore disease, but it isn't as effective in our climate.
Questionable
Remedies
Repellents
Actually planting castor beans or
another plant they dislike called gopher or mole spurge (Euphorbia
lathyris) can work, but they work in such a limited area (immediately
around the plant) that they aren't very practical. Sonar/sound
repellents are available and their effectiveness is questionable. They
also have the same drawbacks as castor beans, only working in a very
limited area. Whirligigs are also sold for repelling moles. Unless you
really are into that look, they aren't very effective either. Another
home remedy that appears in old books and articles is putting used
kitty litter, dog or cat hair into the runs. Since moles rarely use the
same run again, this doesn't work well either.
Minimizing Food Source
One of the old-standard ways to
control moles was to poison their food source. This shotgun method may
kill some of the grubs and such, but also kills a tremendous number of
beneficial soil insects and upsets the balance of microorganisms in the
soil, causing further problems. If chemicals are used, carefully follow
all directions and precautions.
Poisons
There are poison smoke bombs sold for
tunneling rodents. These can work but are incredibly difficult to use.
As often as not, you will find smoke seeping from a dozen spots you
didn't know about in the yard. There are also poison pellets on the
market, but since moles only eat live insects, this method does not
work.
Recommended Products
Shotgun Mole Repellent
Compression and Hose-End Garden
Sprayers
Quality Tools and Gardening Gloves
Grass Seed and Lawn Fertilizers