Online Gardener's Handbook 2010
Chapter 1: Causes of Plant Injury
- The Larger Pests
The Larger Pests
Rats and Voles
In winter, mice live under the snow, travelling in and on
the soil. They can become a problem when their normal food source is scarce. The
damage they cause to bark, roots and lawns is not noticed until spring.
can cause significant damage to young trees and perennials by girdling the lower
stem and by feeding on the roots and crowns of perennials. Meadow voles usually
feed on grass seeds and herbs but shift to bark in fall and winter.
Avoid rodent infestations in home gardens by eliminating sources
of food, water or shelter. For example, keep garbage cans, recycling bins, compost
boxes and all other sources of food (e.g. bird seed) covered and remove all potential
areas near gardens where rodents can build nests (e.g. lumber piles, firewood
stacked close to the ground). Keep areas near gardens well mowed, as tall grass
provides protection for voles.
Place wire mesh tree guards around young
trees, pushing them into the soil to a depth of 5 cm and surround them with stones
to prevent digging. Maintain a grass free area around young trees and shrubs,
and keep all grass mowed short to prevent the creation of a desirable environment
for the animals to live and feed in during the summer and fall.
may be available for domestic use. Animals are repelled by the bitter taste but
are not harmed. For a list of repellents and baits allowed under the Cosmetic
Pesticide Ban, refer to the Ministry
of the Environment website. Brush or spray repellents on bark or on the ground
in a protective band around trees (refer to the product label for specific instructions)
in late fall before a major snowfall. Temperatures should be above freezing. Apply
when the bark is dry and rain is not expected, so that the repellent will dry
thoroughly. One treatment properly applied gives protection until spring. Place
crushed stones around the base of plants to prevent mice from feeding below the
treated bark or on the roots. Severe infestations are rare in a normal urban garden,
and are usually only a problem in rural areas.
are small, plump, short tailed burrowing animals with no visible ears and small,
poorly developed eyes. They spend most of their lives underground, burrowing constantly
in search of worms, grubs and other soil insects. They can cause serious damage
by lifting roots of perennials, bulbs, lawns and strawberry and raspberry patches.
The tunnels they create let in air that dries out the roots.
Set live traps to catch moles and release them elsewhere. Specially
designed mole traps work on trip mechanisms, which the mole pushes as it tunnels
through an existing burrow.
when food is scarce, rabbits eat bark, twigs and buds of fruit trees and many
ornamental trees and shrubs. When snow surface is frozen, they can reach a considerable
height. If completely girdled, trees, shrubs or single branches die. Rabbits can
also be a problem in the vegetable garden in the summer. Damage due to rabbits
is usually a more serious problem in rural areas.
tree guards (available at garden supply stores) or chicken wire around individual
trees or shrubs. Guards must be tall enough to give protection under highest possible
snow conditions. In the summer, vegetables can be covered with chicken wire netting,
or a chicken wire fence can be placed around vulnerable areas of the garden. Fences
should be sturdy and partially buried, to prevent burrowing underneath it.
or spray repellents on bark of fruit trees, ornamental crabapples and other susceptible
woody plants in late fall before a major snowfall. Temperatures must be above
freezing. Apply when bark is dry and rain is not expected, so that the repellent
can dry thoroughly. One treatment properly applied gives protection until spring.
Rabbits, deer and rodents are repelled by the bitter taste but are not harmed.
For a list of repellents allowed under the Cosmetic Pesticide Ban, refer to the
Ministry of the
up lawns searching for grubs.
to reduce grub populations in lawns will minimize the food supply for skunks.
See Chapter 7 for suggestions on how to reduce grub
populations in lawns.
may strip bark from maples, eat buds off trees and rhododendrons, nibble on cherry,
peach, pear and apple fruits, dig up bulbs and plant acorns and black walnuts
where they are not wanted.
pieces of galvanized wire netting over newly planted bulbs using pegs or rocks.
a 45-50 cm sleeve of aluminum, such as those used on roofs, around the tree trunk
to prevent squirrel damage if there are no other trees from which the squirrels
can jump. Strips should be at least 2 m tall. One end is nailed down at the corners
and the other end is tucked under to hold it in place. Allow enough length for
trunk expansion as tree grows and loosen nails periodically so the corners do
not become embedded in the bark. Branches hanging lower than 2 m should also be
pruned off. The same method can be used to prevent porcupines from climbing a
tree to feed on bark.
Woodchucks or Groundhogs
or woodchucks can be found in a variety of habitats: fields, old pastures, fence
rows, gardens and backyard hedges. They feed on grasses, clovers and succulent
garden plants. They may also damage fruit trees or ornamental trees by gnawing
the bark, and ruin root systems by digging burrows.
Control must be a neighbourhood activity, to prevent animals entering
from adjacent property.
Wire fencing around the garden may help stop groundhogs
from digging under. Bury the base to a depth of 15-20 cm and turn it outward in
a trench, causing groundhogs and woodchucks to dig on an angle.