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Keeping an eye out for vole activity

November 24, 2018

Be on the lookout for voles around fruit trees, shade trees and windbreak. Trunks and roots of apple trees are a favorite winter meal of these critters, but they feed on a variety of plants.

Voles are small, mouse-like rodents that exist throughout Nebraska. Though commonly called meadow or field mice, they are distinguished them from true mice by their short (about one inch long) tails, stocky build, and small eyes.

Voles also damage lawns, shrubs and garden plants. Bulbs are another favorite food. Lawns and shrubs often recover from vole feeding; and while garden plants can be killed they are usually less costly to replace.

Economic vole damage occurs mainly to tree plantings, especially orchards and windbreaks. Vole feeding can be severe enough to girdle trunks and kill trees.

Vole populations are cyclic, meaning there is a dramatic increase in voles during some years and then the population crashes. Populations can increase from 10 to 250 voles per acre in a fairly short period of time. High populations usually last about one year.

In fruit orchards and windbreaks, monitor for voles by placing baited mouse traps inside PVC or other pipe near trees. Insert the traps far enough so pets or birds are unable to reach them. Check the stations once a week and reset traps if necessary.

To minimize feeding in orchards and windbreaks, modify the habitat to make it less attractive to voles. High populations cannot become established without food and protection from predators like snakes, hawks and coyotes.

Control grass and weeds around young trees and shrubs through cultivation, herbicides, and mowing. When clearing grass and weeds, do not damage tree trunks with equipment. And follow label directions when using herbicides as these products can significantly damage trees.

Mulch used around the base of trees should be no more than four inches deep and not be piled against tree trunks. Unfortunately, voles often thrive under weed barriers laid on the ground to control weeds around trees and young windbreak plantings.

Exclusion can be used to protect highly valued trees. Use one-fourth inch mesh hardware cloth or plastic cylinders on individual trees. Cylinders should be tight to the ground or buried slightly and extend higher than the expected snow depth of winter. Overlap cylinder edges at least 1 inch and fasten securely so gaps do not form that allow voles to enter.

Cylinders of galvanized hardware cloth can last about five years, so make them large enough in diameter to accommodate trunk growth if they are to remain in place for a few years. Be sure to eventually remove these as they too can girdle trunks. Cover the tops of cylinders to prevent trapping cavity-nesting birds.

Repellents made with thiram and capsaicin are registered for reducing vole damage on ornamental plants. They are not registered for use on gardens or plant parts meant for human consumption. Coyote and fox urine may help disperse voles. They’ve also been proven to increase stress which reduces vole reproduction. Follow all label directions when using repellants.

For additional information on voles and other control methods, refer to www.extensionpubs.unl.edu and do a search for voles.

Kelly Feehan is a community environment educator for Nebraska Extension.

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