Voles, also known as meadow mice, are among the array of pests that can cause severe damage to a garden. Voles form complex underground tunnels that disrupt and damage root systems and feed on and collect vegetable crops for winter storage. Controlling voles is essential for a healthy garden.
Voles resemble mice, measuring five to eight inches including the tail. They have coarse, brownish fur that may have highlights of black or gray. Voles are short-legged with a short, fur-covered tail. Their eyes and ears are also small. Although they resemble mice, they do not enter homes.
Voles tunnel and nest underground, connecting burrow entrances with aboveground runways that pass underneath grass and other protective vegetation. Voles remain active throughout the year and during both the day and night. Although they are short-lived, rarely living more than a year, they are prolific, and a female may produce up to 60 young per year. According to the University of California Statewide Integrated Pest Management Program, vole populations fluctuate depending on conditions, sometimes increasing to several thousand per acre before subsiding once again.
Voles cause damage to a variety of vegetable plants, primarily greens and root vegetables, as well as some ornamental plants. Voles also chew the bark on trees, a process known as girdling that interrupts the flow of nutrients from the leaves to the roots. Girdling can kill a tree. Gnaw marks can be seen on some plants, and the occurrence of greenish-colored droppings and "runways" further indicates a vole problem.
As with most garden pests, preventing voles is the best strategy for avoiding garden damage. Keeping garden beds free of weeds and crop litter limits the habitats available to voles. Regularly mowing grass also keeps populations down because they cannot use the grass to form protective runways. To exclude voles from your garden, the Rutgers Cooperative Extension recommends a metal barrier at least 1 foot high with 1/4-inch or smaller mesh. Frequently tilling the soil also destroys burrows and controls the population.
If voles have already infested your garden, there are strategies for controlling them. According to Rutgers Cooperative Extension, most repellents, fumigants and frightening devices will not work for voles. Snap traps baited with apples or peanut butter and placed at the entrance to a burrow can help you to catch existing pests. In addition, cats are natural predators of voles.