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breed almost year around, although most
<br />reproduction occurs in spring, summer and
<br />fall. Females may become pregnant at three
<br />weeks of age.
<br />Damage and Control
<br />Voles can cause extensive damage to
<br />forests, orchards and ornamental plants
<br />by girdling trees and shrubs. They prefer
<br />the bark of young trees but will attack
<br />any tree, regardless of age, when food is
<br />scarce. Monitor orchards frequently so
<br />control measures can be implemented
<br />before appreciable damage occurs. Most
<br />damage occurs in the winter when voles
<br />move through their grass runways under
<br />the protection of snow. The greatest
<br />damage seems to coincide with years of
<br />heavy snowfall.
<br />Damage to crops, such as alfalfa, clover,
<br />potatoes, carrots, beets and turnips is
<br />common and most evident when voles are
<br />at high population levels. Runways and
<br />tunnel systems constructed in agricultural
<br />fields can divert irrigation water. Voles
<br />often damage lawns and golf courses by
<br />constructing runways and burrow systems.
<br />Vole damage to trees and shrubs is
<br />characterized by girdling and patches of
<br />irregular patterns of gnaw marks about
<br />1/16 to 1/8 -inch wide. Gnawed stems
<br />may have a pointed tip. Do not confuse
<br />vole damage with damage by rabbits,
<br />which includes stems clipped at a smooth
<br />45- degree angle and wider gnaw marks.
<br />Stems browsed by deer usually have a rough
<br />jagged edge. Voles also girdle the roots of
<br />trees and shrubs.
<br />Other signs of damage by voles include:
<br />1) 1- to 2 -inch -wide runways through
<br />matted grass and burrows; 2) visual
<br />sightings; 3) hawks circling overhead and
<br />diving into fields; and 4) spongy soil from
<br />burrowing activity. Trees that appear to
<br />suffer from disease or insect infestation may
<br />be suffering from unseen vole damage.
<br />Methods to prevent and control damage
<br />are: habitat management, exclusion,
<br />Moles vs. Voles: Moles are found only
<br />in extreme SE corner of Colorado.
<br />Moles have a distinct pointed nose,
<br />rounded front paws with conspicuous
<br />claws. Moles are also solitary, only
<br />coming together for mating. Voles
<br />may have several generations living
<br />together in shared tunnel systems.
<br />repellents, trapping, and poison grain baits.
<br />Voles are classified as non -game wildlife in
<br />Colorado and may be captured or killed
<br />when they create a nuisance or cause
<br />property damage.
<br />Habitat Management. Elimination
<br />of weed ground cover and tall grasses by
<br />frequent and close mowing, tilling, or
<br />herbicide application is the most successful
<br />and longest lasting method to reduce vole
<br />damage to orchards. This will diminish the
<br />amount of available habitat and reduce
<br />their numbers. Prunings left in orchards
<br />prevent proper mowing and provide a
<br />temporary food source, which may lead to
<br />damage by voles. Planting short grasses that
<br />do not mat or lodge, such as buffalo grass,
<br />blue grama, or dwarf fescues, will provide
<br />little protective cover and may reduce
<br />vole numbers.
<br />Meadow voles are active during the day
<br />within their runways under thick grass and
<br />vegetation Summer removal of vegetation
<br />(2 feet of trunks of fruit trees) provides
<br />some protection because voles avoid
<br />exposed areas.
<br />Damage to lawns can be reduced by
<br />close mowing in the fall before snow arrives
<br />and by mowing and removing tall grassy
<br />cover near lawns. To repair damage to lawns
<br />from runway construction, rake, fertilize
<br />and water the effected area. Close mowing
<br />and weed control in grassy borders adjacent
<br />to agricultural crops will reduce the habitat
<br />for voles and should reduce damage. If
<br />suitable, plant crown vetch (a legume
<br />unpalatable to voles) in orchard and field
<br />boundaries to reduce vole populations.
<br />Important predators of voles are:
<br />short -tailed shrews, badgers, coyotes,
<br />foxes, bobcats, barn owls, great horned
<br />owls, long -eared owls, short -eared owls,
<br />barred owls, screech owls, and some snakes.
<br />Predators will not likely keep an orchard
<br />vole -free, but they can help reduce the vole
<br />population. Orchardists should tolerate
<br />predators and protect them if they do not
<br />constitute a pest problem.
<br />Exclusion. To protect against vole
<br />damage, encircle young trees and shrubs
<br />with 1/4 -inch mesh hardware cloth
<br />or 3 -inch diameter Vexar plastic -mess
<br />cylinders. This barrier should project 18
<br />inches above the ground and 3 to 6 inches
<br />below the surface. Vegetable and flower
<br />beds may also be protected in this manner.
<br />Repellents. Only a few repellents
<br />(including thiram and Hot Sauce, or
<br />capsaicin) are manufactured to protect
<br />trees, shrubs and vegetable crops from
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<br />Methods to prevent and control
<br />damage are: habitat management,
<br />exclusion, repellents, trapping, and
<br />poison grain baits. Voles are classified
<br />as non -game wildlife in Colorado and
<br />may be captured or killed when they
<br />create a nuisance or cause property
<br />damage.
<br />voles. Little data are available on the
<br />effectiveness of repellents to deter vole
<br />damage. However, in one study, thiram was
<br />reported to reduce damage to apple stems
<br />by 78 percent. A 20 percent solution of
<br />chicken eggs in water has been effective in
<br />reducing deer and elk browsing and may
<br />reduce damage by voles.
<br />Thiram is manufactured by various
<br />companies and sold under various trade
<br />names. Thiram products are labeled for
<br />protecting most of the following from
<br />voles: tree seedlings, shrubs, ornamental
<br />plantings, nursery stock, and fruit trees.
<br />Most labels limit the use of thiram on fruit
<br />trees to the dormant season.
<br />Capsaicin (the "heat" in spicy peppers)
<br />is labeled for use on ornamental trees and
<br />shrubs, fruit and nut trees, fruit bushes
<br />and vines, and nursery stock to protect
<br />them from vole damage. Limit application
<br />to fruit - bearing plants before fruit sets
<br />or after the fruit is harvested. Hot sauce
<br />also is registered for use on beans, corn,
<br />cucumbers, melons, peas, brussels sprouts,
<br />squash, peppers, tomatoes, cabbage, and
<br />cauliflower before edible portions and /or
<br />heads begin to form.
<br />Another product that is available that is
<br />labeled for voles is Rucinus Communis Oil
<br />(Castor Oil). Though its effectiveness is not
<br />known, it is labeled as safe around children
<br />and pets.
<br />Predator odors, such as the urine
<br />from red foxes and coyotes, also may be
<br />effective vole repellents. These odors are not
<br />commercially manufactured, but fox and
<br />coyote urines can be purchased from some
<br />trapper supply houses.
<br />Because products change often, visit the
<br />Colorado State University Extension Home
<br />Use Pesticide Database online at http: //
<br />wsprod .colostate.edu /cwis487 /hup /Default.
<br />aspx for up -to -date product descriptions.
<br />Trapping. Use mouse snap traps to
<br />remove small populations of voles from
<br />backyard lawns. Place traps perpendicular to
<br />runways with the trigger end in the runway
<br />and bait with small amounts of rolled
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