Match the offense with the right offender
The ridges of mole tunnels make lawn mowing difficult, but moles don't eat plant roots. Grubs do. And moles eat grubs. So do shrews, which use mole tunnels as runways and travel lanes.
So if you can live with a few ridges in your yard, you may want to spare moles and shrews, which do a good job of controlling ornamental-plant-eating grubs.
Meadow mice, on the other hand, eat a wide variety of vegetative matter and may damage plant life. The general similarity in color and appearance of moles, shrews and meadow mice and their tendency to associate in the same habitat and runways make it essential to understand differences in their habits and to know how to identify each species in the event it becomes necessary to control them.
Changing environment. You can prevent moles from becoming established or can control them once they start digging tunnels by reducing their insect food supply. While this method may take time to become effective, its benefits will persist as long as the animal organisms on which moles feed are kept at a low level. (Note: Such treatment will likely kill earthworms and may discourage bird life.) When used according to the directions on the label, chemical soil treatment to control grubs and other soil insects can provide a safe and satisfactory solution to mole damage. Check with county extension offices for current soil insect treatment.
Trapping. Moles can be captured by using specially designed traps. Harpoon and choker type traps are available through farm- and garden-supply stores or hardware stores. Directions for using these special traps are furnished by the manufacturers.
The selection of actively used runways is important for successful trapping. To determine active runways, press down short sections of the raised ridges and mark these locations. Active runways will be repaired as moles continue to feed and travel, while abandoned tunnels will not be repaired.
Select a fairly straight two- or three-foot section of one of these major runs that has been repaired. Stomp down the middle with your heel to create an obstruction in the tunnel. The trap should be placed over this obstruction so that the mole will spring the trap as it repairs the tunnel. Set your trap according to the instructions included with it, and carefully trigger it a couple of times to see if it is working properly.
A good test to check whether you have a good trap location is to punch a small hole in the run on both sides of the trap with a stick. Moles do not like light and will plug the holes. Later, if the trap is not tripped but the holes are plugged, the animal has passed by but missed the trap. In that case, strike the burrow two or three times with your heel to collapse the new tunnel, and reset the trap. If the trap is not sprung and the holes are not plugged after two days, you probably should move the trap to another location.
When temperatures are cold or hot, moles spend most of their time in the deeper burrows. Therefore, you are more likely to be successful at trapping moles in the spring or fall.
Mechanical. Small areas such as flower beds can be protected by barriers of sheet metal buried in the ground to a depth of at least 12 inches, so as to prevent burrowing.
Pesticides. A number of chemicals are registered and available for use in mole control. However, they are not always effective. Fumigating gases leak from the surface burrows, and toxic baits may not be eaten because of the moles' preference for eating insects and other soil organisms. For these reasons, pesticides are seldom suggested to control moles.