For more information about voles and how to control them, we recommend contacting your local extension agent, as well as reviewing the following documents:
NC State Extension: Voles in Orchard and Ornamental Plantings
University of Missouri: Controlling Voles in Horticulture Plantings and Orchards in Missouri
University of New Hampshire: Managing Voles in New Hampshire Orchards and Highbush Blueberries
Those pesky voles - what they do to chestnut trees and how to fight them
Paul Sisco and Sara Fitzsimmons
Originally published in the magazine, Chestnut, Winter/Fall 2017-2018 Issue
Ever had a small chestnut tree die for no apparent reason, tug on it, and have it come right up from the ground missing its root system? Or see a tree leaning? Or notice that bark is missing around the base of one or more of your trees?
If so, you've probably got a vole problem. What are voles? For one thing, they are not moles. Moles are small furry critters with pointed noses that eat insects and earthworms. Moles are Meat-eaters. Voles are small furry critters with blunt noses that eat plants, including grass, roots, and (unfortunately) chestnut trees. Voles are Vegetarians.
In the Eastern US we are usually dealing with one of two vole species, the Meadow Vole (Microtus pennsylvanicus [Ord]) or the Pine Vole (Microtus pinetorum [LeConte]). Meadow voles are larger with longer tails and big eyes, while pine voles are smaller with short tails and very small eyes. Meadow voles are poor tunnelers. They often follow mole tunnels along the soil surface. So they mostly do damage by eating bark just above the soil surface. Pine voles are very good tunnelers, and they live in burrows up to a foot deep. Thus their small eyes. They can be very destructive to tree roots.
Voles are prolific. They put rabbits to shame. Since they multiply quickly with several generations per year, it is important to battle them proactively. The first way to potentially prevent vole damage is with good vegetation control. Voles generally prefer to stay hidden under lots of grass. If you remove the grass via herbicide sprays or keep the grass very, very short, this leaves many voles visible to birds of prey and other predators. Another method is to exclude them from the tree via protective cages or tubes.
Unfortunately, these methods are not foolproof. Pine voles can tunnel under barriers to the depth of a foot. Some vegetation control methods such as mulch or landscape fabric exacerbate vole problems by giving them a place to hide. Even when appropriate cultural controls are followed, voles can seek cover in the winter under blankets of snow, and chestnut orchardists often discover extreme vole damage after heavy snowfall years. When all else fails, the best method is toxic vengeance.
There are several toxicants available for vole control, but use them wisely and be sure to check with your local extension agent about their use. These chemicals are not specific to voles and can lead to widespread collateral damage. For that reason, the best method for applying these toxicants is in bait stations where only burrowing creatures are likely to go and then stay. For about $5 a piece, one can fashion a t-shaped bait station out of PVC pipe. By placing several of these near vole runs, one is likely to have the voles enter the trap, take the lethal bait, and stay underground to perish.
Voles often do their worst from late fall through early spring. Therefore, bait stations should be placed in the fall on/near existing vole runs so they may be effective through the winter months.
