Stella Otto: The Backyard Fruit Gardener

Today's Tip: Mow vegetation short around the base of fruit trees and bushes to reduce winter habitat for rodents.

Rodents — Pests of the Winter Fruit Garden

Worms, wee­vils, rots, and molds are typ­i­cally the first “evils” that come to mind when talk­ing about pest prob­lems in the fruit gar­den. Many gar­den­ers, how­ever, real­ize that wildlife pests can be just as  prob­lem­atic. Voles, mice, rab­bits and deer keep fruit gar­den­ers on their toes dur­ing the win­ter sea­son. You can out­wit them though. Know­ing how par­tic­u­lar wildlife behave will give you tools to help send them off to other for­ag­ing grounds.
Voles, mice, and rab­bits nor­mally do their great­est dam­age to fruit trees and bushes dur­ing the win­ter when food is scarce. They par­tic­u­larly enjoy the ten­der bark of young fruit trees. As rodents feed on the tree bark, they can gir­dle the plant near its base. Sev­eral pre­ven­tive steps can be taken, as win­ter approaches:
●    Late fall mow­ing of grass under­neath and around trees or bushes reduces win­ter nest­ing sites near the fruit gar­den.
●    Rak­ing mulch back, away from the trunk, is another deter­rent to rodents estab­lish­ing win­ter nests.
●    Wrap­ping young trees’ trunks with 1/4 inch hard­ware cloth or plas­tic spi­ral guards designed for this pur­pose can help pro­tect them. It is impor­tant that the guard touch the soil sur­face so rodents do not have access from below. They should also be tall enough, usu­ally 18 to 24 inches, that  mice trav­el­ing on the snow sur­face will not enter eas­ily from above.
●    Gar­den­ers who paint their tree trunks with latex paint, for the pre­ven­tion of sun­scald [LINK] may also notice a reduc­tion in rodent feed­ing. Some grow­ers feel adding cop­per enhances the deter­rent effect.

Know your pest —
Voles
Voles - winter nemesis of fruit trees

Voles — win­ter neme­sis of fruit trees

What many gar­den­ers call mice are actu­ally voles. Voles are active at any time of day and mainly build bur­rows in dense veg­e­ta­tion on the soil sur­face. Thus, keep­ing a weed-free strip or area at least 4 foot in diam­e­ter around your fruit plants is a good idea. Voles will bur­row through the snow and feed on tree trunks if there is suit­able habi­tat in your gar­den. They may also feed on shal­low roots just below the soil sur­face. Often this leads to dam­age that goes unde­tected until not much can be done to save a severely gir­dled tree.
Var­i­ous Micro­tus species are found in dif­fer­ent parts of the coun­try. All are pro­lific breed­ers with high pop­u­la­tion num­bers cycling over a 3 to 6 year time-frame. Voles are typ­i­cally 5 to 8 inches from nose to tail tip, with coarse black­ish to greyish-brown  fur. They are rel­a­tively fat and round-bodied with stubby legs and small ears and eyes. More detailed infor­ma­tion on
meadow voles and their man­age­ment, check this out.

Rab­bits

Rab­bit dam­age to fruit gar­dens dif­fers a bit form vole dam­age in that it is often found above the snow line. Once the gar­den is cov­ered in snow for 10 days to 2 weeks or more and a crust is formed on the sur­face, rab­bits are inclined to visit fruit trees and berry bushes or canes. Much like voles, they too will gnaw on the bark, just higher up on the plant.  Rab­bits will feed on young, ten­der bark as well as low– grow­ing shoots. Rab­bit feed­ing is char­ac­ter­ized by being a clean 45 degree cut. They tend to leave mature, tough, older bark alone unless food is extremely scarce.
Tracks and tell-tale drop­pings will often give clues to their visit as well. Occa­sion­ally, I have seen rab­bits form a bur­row right within a shel­tered bush; so pay atten­tion to where the tracks lead. To deter rab­bits, it is often nec­es­sary to be sure that tree guards reach suf­fi­ciently above the snow line. More on rab­bit habits and con­trol can be found here.

Deer

Deer can become a seri­ous pest of the late winter-early spring gar­den. They often feed on gar­den plants when other food in their win­ter yards becomes scarce. In con­trast to rab­bits, deer feed­ing will be more of a rip­ping of the branch and higher up on the plant. We’ll have more on deer brows­ing and how to dis­cour­age it in early spring.

Properly fitted mouse guard extending from the soil line to the lowest branches of the fruit tree

Prop­erly fit­ted mouse guard extend­ing from the soil line to the low­est branches of the fruit tree

Tips for using rodent guards

●    Use guards that are of suf­fi­cient length to pro­vide pro­tec­tion above the snow line.
●    Guards should be pushed an inch or so into the soil to dis­cour­age root feed­ing.
●    Make sure spi­ral type guards are not stretched out by larger diam­e­ter trees leav­ing exposed trunk areas where rodents can still feed..
●    Remove plas­tic guards in the spring and reap­ply them in the fall. If left in place, check to make sure they do not become hid­ing places for trunk bor­ing pests.
●    As trees grow and expand and guards set­tle into the soil, make sure that the soil is not con­fin­ing the bot­tom of the guard and caus­ing it to stran­gle the trunk below ground.

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