Recently the Extension office has received calls from homeowners who have observed the appearance of tunnels in the soil and small holes in the ground. Often they are caused by the actions of small animals called moles and voles.
What exactly are these animals and how are they different? Moles feed on insects. Moles are flat, pig-nosed, gray animals 5 to 6 inches long. Moles have large incisor and canine teeth. They possess powerful front feet used to tunnel below ground and are rarely observed above ground.
Their diet consists of earthworms, white grubs, ants, beetles and other subterranean insects. They do not feed on plants. Their tunnels can potentially damage a young plant's root system. A large network of the raised tunnels dug by a few moles can ruin a lawn's appearance. The mole population peaks in the fall.
Voles are rodents resembling a house mouse but have a shorter tail and smaller ears. They are brown to gray in color, 4 to 6 inches long with mouse-like chewing teeth but no canine teeth. Voles feed on plant roots, bulbs and other parts of vegetation. They damage plant material by chewing the roots of young trees and shrubs, and can strip the bark at ground level. Voles travel above ground. Their paths are called runways and can be identified as worn paths in the grass and ground litter.
Moles and voles damage lawns and gardens differently. Mole damage is usually only cosmetic. They plow the soil by tunneling just under the surface in search of grubs. Mole tunnels can make turf look "cracked" and in closely mowed turf, their tunnels can become unsightly, especially with the volcano-shaped mound built around their exit hole.
Voles feeding on ornamental plants will girdle the trunks and damage the roots by chewing. Root tips look like sharpened pencils. Often you will not suspect the damage until the plant just falls over. Voles are active both day and night.
Moles can be difficult to control. Reducing their food source is one method. Grubs are one of their favorite foods and often what attracts them to an area. Applying insecticides labeled for controlling grubs can reduce the damage caused by moles.
Another control method is the use of lethal harpoon traps placed over their tunnels. The traps are set off by mole movements. Step on their runs in several places, marking the spots. The moles will repair the tunnels they use. Go back to these spots and observe the repairs. Do this several times. Then place the traps on top of these runs.
Control voles by reducing the amount of groundcover by mowing or some other means. This is the best way to deter voles from inhabiting an area since they prefer plenty of groundcover to protect them from predatory birds and mammals. Traps may also be used. Snare traps and snap traps (traditional mouse traps) can be placed in runways and baited with apple slices. A good method is baiting the traps with small amount of peanut butter for few nights without setting the traps. When the traps are finally set there is an element of surprise.
Another method of controlling vole damage is to create a "fence" out of hardware mesh cloth and wrap it around the base of the woody plants to deter them from chewing on the bark. Baits or poisons are not available for homeowners to use in controlling voles.
Timothy Daly is and Agricultural and Natural resource Extension Agent with Gwinnett County Extension. He can be contacted at 678-377-4010 or firstname.lastname@example.org.