Voles, also known as meadow mice, are members of the rodent family. Their compact, heavy bodies are five to eight inches long counting the short furry tail. Their fur is blackish brown or greyish brown. They have tiny eyes and long snouts. Voles can do tremendous damage in the garden and landscape where they feed on roots, bulbs and bark, unlike their cousin, the mole, which eats grubs. Voles can gnaw the bark all the way around a fruit tree causing a serious threat to the tree's life, and eat tulip and crocus bulbs when they've barely sprouted.
Habit and Habitat
Voles burrow underground, and they make many holes in the ground one and one half to two inches in diameter. They create runways under ground covers to reach their burrows. Voles prefer not to be out in the open and thrive in areas of dense vegetation and ground cover. Their shallow tunnel systems are short but may contain several adults and their young.
Outdoor cats will prey upon voles. They are natural enemies and can help reduce the vole population in your garden. Ratting dogs such as Jack Russell terriers and similar breeds will hunt and capture voles, according to Mike McGrath of You Bet Your Garden.
Managing the Population
The University of California Pest Management division recommends practices to manage and reduce the population of voles. One of these is to reduce or remove vegetative cover which will make the habitat less suitable. Create buffers around the garden by closely mowing or spraying an herbicide in a strip about 15 feet wide around the perimeter to prevent weeds.
To keep voles out of the garden, you may want to try fencing around the perimeter with mesh fencing of one quarter inch or less. Sink the fence at least 6 to 10 inches under the ground and reinforce with a weed-free barrier, as well. This may be practical for a small vegetable garden but it wouldn't be for vole problems in the larger landscape.
Baits that work for mice will also work for voles. Anticoagulant baits, which come in pellet form, interfere with the blood clotting process and are considered safe for home and garden use. Place the pellets in the runways, under the ground cover. For large areas, broadcasting the bait may be required. Rodent baits can be found in retail stores and farm cooperatives.
You can use mouse traps for trapping voles by putting peanut butter or an apple slice on the trigger mechanism. Place the trap perpendicular to the runway with the trigger end on the runway, says Rutgers University Cooperative Extension experts. A dozen or so may be enough traps for a small garden. A large area may take 50 or more. Continue to place traps on the runways until you are not catching any more voles.
Repellents and Fumigants
People try all types of methods to get rid of these pests, such as flooding the burrows, using electromagnetic or ultrasonic devices, fumigation or spraying repellents. The University of California Pest Management team and the Rutgers University Cooperative Extension insist that these techniques are not very effective.