Moles

Question:

I have a huge problem with a critter that burrows under the sod, leaving soft spots all over. It does not mound, so there are no holes to treat. There are too many tunnels to attack. My plants and veggies are dying by the truck load because all the soil is dug up.

Minnesota Master Gardeners say:


Most likely an eastern mole is at work on your property. Take a shovel and remove a section of the pressure ridge or tunnel. Make a clean, vertical cut on each end of the section, perpendicular to the ridge. You should see a perfectly round hole about two inches in diameter.

The star-nosed mole is also found in Minnesota, but it is less common and usually digs its burrows in very wet or even marshy soil.

Moles eat soil insects such as earthworms, white grubs, and beetles. When they dig in soft moist soil they are capable of extending their tunnel system 18 feet an hour. In an established runway they can clip along at about 80 feet a minute. Although they do not eat plants or the roots of plants as pocket gophers do, their tunneling activity often does disturb and damage the roots of turf and garden plants.

If you are not sure what animal is burrowing in your yard, read "What's digging holes in my lawn, yard or garden?" at _URL____.

Trapping

Trapping is the most effective means of control. Three types of traps are available: harpoon, scissors-jaw, and choker loop. The harpoon trap is the easiest to use since there is no need to disturb the soil when setting the trap over the runway. Traps are available at most hardware and garden stores. Instructions for their use are on the box. Wear heavy leather gloves when working with traps.

If you have tried mole trapping with little or no success, read Tips for Mole Trappers at _URL ____.

Repellents

Gas bombs, poison peanuts, chewing gum, and human hair are not effective controls. Neither are devices purported to repel moles by emitting annoying sounds or electrical impulses.

Although there is no university research supporting the claim, some people have reported success using castor oil based repellents. Several commercial products are available for this purpose. If you want to try the castor oil repellent, you can make your own. Mix 6 ounces of castor oil and 2 tbsp of dish soap in one gallon of water. This becomes the concentrate. Mix one ounce of concentrate per gallon of water and apply to the lawn. If it rains, reapply.

Barriers

If the area you want to protect is small you could try surrounding it with galvanized hardware cloth or aluminum sheeting buried to a depth of 24 inches and extending 6 inches above ground.

Habitat modification

Some advocate using pesticides to kill the grubs upon which the moles feed. These products kill all soil insects, including those that are beneficial. Consequently, use of these pesticides is not encouraged. Moreover, since the moles will not know that the lawn has been treated with the pesticide they may still make forays into the lawn in search of food.

Much information about mole control is available on the Internet.

The U of M Extension Service has two articles on moles that may be helpful:
http://www.extension.umn.edu/info-u/environment/BD592.html and
http://www.extension.umn.edu/distribution/naturalresources/DD1139.html

Specialists at Nebraska, Pennsylvania and Missouri have prepared excellet web sites on this topic. Most of the information there applies to Minnesota.
http://www.extension.psu.edu/ncregion/ag_natural_resources.htm
http://muextension.missouri.edu/xplor/agguides/wildlife/g09440.htm
http://www.ianr.unl.edu/pubs/wildlife/g1288.htm
The following article from Manitoba is useful, because it has diagrams and describes trap placement and how the burrows are constructed. It also explains the differences between mole and gopher burrows.
http://www.gov.mb.ca/agriculture/crops/forages/bjb00s26.html#habits