Northwest berry Foundation

Management Detail


in Blueberries

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Latin name: Microtus spp.


Reason for Concern:
1) Voles, also known as field mice, can be a very serious problem in blueberry plantings.
2) They feed on the bark of stems, fruit and foliage near the ground, or on the roots, depending on which species of vole is present.
3) Their gnawing and chewing can girdle roots, crowns, canes, and the trunk of the plant.
4) Subterranean feeding activity also creates air pockets along the root zone.

Voles are small, mouse-like rodents distinguished from true mice by their short tails (about 1 inch long), stocky build and small eyes. Presence of voles is indicated by chewing marks on canes and roots. The runways are usually hidden beneath a protective layer of grass or other ground cover. Although voles do spend considerable time aboveground, most is spent below ground in their burrow system. Voles often leave open, 1-1/2 to 2 inch holes in areas of heavy activity (moles always seal up their holes). Fresh clippings of green grass and greenish-colored droppings about 3/16 inch long in the runways and near the burrows are further evidence of voles. With age, the droppings lose the green coloring and turn brown or gray.

Voles are active day and night, year-round and normally found in areas with dense vegetation. Several adults and young may occupy a burrow system. Vole numbers fluctuate from year to year. Voles may breed any time of year, but the peak breeding period is spring. Females mature in 35 to 40 days and have 5 to 10 litters per year. Litter size ranges from 3 to 9. They rarely live more than one year.



  • Look for tunnel entrance holes about one inch in diameter, surface runways in sawdust or grass row middle and chewing marks on bark and roots.
  • Look for fresh trails in the grass.
  • Pay particular attention to adjacent areas that have heavy vegetation because such areas are likely sources of invasions.
  • Vole populations can be monitored by use of bait stations, which are protected shelters (e.g., a roof shingle) covering a runway or tunnel entrance and baited with apple wedges (chewing on the apple wedges indicates vole activity).
  • PVC Bait stations can also be used for monitoring and control. Go to the Ontario Woodlot Association for information on bait stations.

Cultural Controls:

  • Habitat reduction can also help reduce vole damage; mowing and managing vegetation along field borders and keeping sod or groundcover between the berry rows mowed aids in this effort.
  • Plant guards for young plants can prevent above-ground vole feeding, and trapping can reduce vole populations.


For information about chemical controls, check with our Pesticide Guide.


Vole damage in blueberries - photo by T. Peerbolt

photographer unknown

photographer unknown

Tunneling made by voles or mice - photo by T. Peerbolt

Vole damage in blueberries - photo by T. Peerbolt

Vole damage in strawberries - photo by T. Peerbolt

Close up of vole damage in strawberries - photo by T. Peerbolt

Mouse or vole damage - photo by T. Peerbolt

Arrow points to teeth marks - photo by T. Peerbolt


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