PURDUE PLANT DOCTOR

Key Features

Symptoms

Rodent and other small animal damage occurs within 10 inches of the ground while deer browse and rubbing will reach to over 5 feet. Common symptoms include branch bark peeled back by squirrels, and girdling (a chewed ring of bark and wood around the trunk) caused by mice and voles. Rabbits (not rodents but lagomorphs) also cause similar types of basal damage. For vole damage, look for lines of disturbed soil leading to shrubs. Gophers and pocket gophers leave mounds of soil near damaged shrubs. Gophers and pocket gophers cut roots of shrubs and vines along with gnawing bark. Both gophers and pocket gophers destroy the roots of plants beneath the surface and then pull the plant into the burrow. Voles eat shrubs, including their roots. Their runways and tunnels cause root damage. They are particularly harmful to the roots of boxwoods. During winters with heavy snowfall, voles will tunnel through the snow to eat bark and evergreen leaves. Voles will also use mole tunnels to feed on plant roots. Voles may cause extensive damage to orchards and woody landscape plants in the winter when they girdle (or chew) the bark from the lower trunks.

Biology

Damage can occur throughout the year, but is more common in late winter when food is scarce, and fall, when creating a den or nest is an issue.

Management Recommendations

Use fencing or plant guards to protect susceptible shrubs from destructive animals. Avoid tight fitting guards because they can increase damage caused by boring insects and canker pathogens. Products containing putrescent egg solids are effective in repelling deer for a short time but should not be used where people may be exposed to the terrible smell. Remove weeds and keep grass mowed low; this limits hiding places for small animals. Maintain mulch levels at 2-3 inches and avoid excessive mulch levels and volcano mulching which provides habitat for rodents. The standard prevention method is to surround trunks with an exclusion zone made of ¼-inch metal mesh or hardware cloth. To protect against vole damage, wrap shrub trunks with 24-inch wide mesh hardware cloth being sure to bury the mesh six inches below the soil surface. To stop rabbits from gnawing on bark, be sure to wrap the metal mesh to above the snowline. You may need to adjust the height of the mesh throughout the winter as more snow falls. Pocket gophers are probably the most destructive and lethal to shrubs. Shrub protection should begin at planting, with hardware cloth surrounding the hole where the shrub is planted. In some states, pocket gophers are a species of conservation concern due to loss of native grassland habitat. Therefore, caution should be taken in the control of their populations.

Effective Pesticides

Pesticides are neither available nor recommended for managing this condition.

Lookalikes

• Animal Damage, Feeding Damage

Resources

• Not satisfied with ID? Contact the Purdue Plant and Pest Diagnostic Lab
• Sign Up for the Purdue Landscape Report