Pest Control Library: Moles
These insect-eating underground dwellers are found throughout the country and prefer to dig in moist loamy soils, avoiding sandy or clay soils when possible. Contrary to popular opinion, most moles don't eat plants. Their diet consists mainly of insects, earthworms, beetles, and grubs. However, their feeding tunnels in spring and summer are shallow enough to disturb lawns and seed beds. Their tunnels can also create runways for rodents such as voles to find your prized flower bulbs or root crops. Moles rarely stay in the same location for long, and if you're patient they will naturally leave your garden in search of other food sources.
You can repel, exclude, or trap moles. Some gardeners have had success repelling moles by placing moth balls, human hair, ultrasonic noise emitters, or predator urine in their tunnels. University research has shown that castor oil sprayed on lawns and gardens will repel moles from your landscape. You can reduce mole populations by eliminating lawn grubs. Spray lawns with beneficial nematodes or milky spore disease to reduce grub populations. You can also create an underground fence of hardware cloth to exclude moles from prized bulb beds or new seedbeds. The best controls for persistent problems are trapping and exclusion. Moles are most active in early morning or evening, and after a warm rain. You can use live traps or lethal traps placed in the main tunnel to eliminate these pests. In small beds gardeners can create cages or baskets to protect prized plants. Dig a 2- to 3-foot-deep hole in the planting area and line the sides and bottom of the bed with wire mesh. Replace the soil and plant your garden. Protect trees with wire mesh guards placed a few inches below the soil line and 2 feet up the trunk.
Photograph courtesy of David Liebman