Microsoft PowerPoint - Insects and Diseases [Compatibility Mode]Spruce budworm
Hemlock looper
Larch sawfly
Hemlock looper
eastern hemlock, jack pine,
Norway spruce, red spruce,
needle
Will kill tree
A native species, the spruce budworm is considered the most serious pest of fir and spruce forests in North America. Its range coincides with that
of fir. Evidence of a spruce budworm infestation includes the destruction of buds, abnormal spreading of new twigs, defoliation of current-year
shoots and, if an affected branch is disturbed, the presence of large numbers of larvae suspended from strands of silk. Defoliation begins at the
top of the tree and quickly progresses to the periphery of the crown from the top downwards. Current-year needles are partially or completely
consumed and, if large numbers of larvae are present, previous-year needles may also be affected. Spruce budworm larvae also feed on staminate
(male) flowers and cones. During epidemics, the larvae may destroy all of the cones.
Larch sawfly
Native insect
tamarack, western larch
Damage type Defoliation
Micro-habitat(s) NeedlesMicro-habitat(s) Needles
Will kill tree
The larch sawfly can be detected by looking for the slits on new shoots in which females have deposited their eggs or checking for
groups of larvae crawling on the branches. Larch sawfly larvae live in colonies (groups) during their initial larval stages and then
scatter throughout the crowns of trees. Larvae feed heavily on needle clusters from mid-May to September, stripping the foliage
from entire branches. Larch is deciduous and can withstand defoliation better than most conifers. However, repeated severe
infestation over many years may result in a reduction in growth, tip dieback, branch mortality and tree mortality.
Hemlock looper
Native insect
eastern hemlock, sugar maple,
white birch, white spruce
Micro-habitat(s) Leaf, needle
Will kill tree
Native to North America, the hemlock looper is considered a serious defoliator in Canada. It occurs from the Atlantic coast west to
Alberta. It has destroyed several million hectares of conifer forests in eastern Canada over the years. The main hosts of this insect are
balsam fir in eastern Canada and hemlock in western Canada but it will also feed on, black spruce, sugar maple, white birch, and white
spruce. Hemlock looper damage is visible on conifers during epidemics in late July and early August. The trees turn a reddish colour,
which is very characteristic of hemlock looper outbreaks. Needles damaged by feeding larvae dry out, turn red and drop in the fall.
Balsam twig aphid
Will not kill treeWill not kill tree
Balsam twig aphids cause curling of the needles and distortion of the shoots, resulting in a gall-like swelling. The aphids secrete copious
amounts of honeydew on the shoots, which allows the growth of a fungus, the sooty mold, further reducing the aesthetic appearance of the
infested shoots. The balsam twig aphid has a holarctic distribution, extending across Europe and North America. In North America, the
insect occurs throughout the range of fir, from the Atlantic to the Pacific Ocean. In eastern Canada, the insect was first reported in the 1930s.
The balsam twig aphid is a secondary pest in natural stands since it does not cause tree mortality.
White pine weevil
spruce, Scots pine, white spruce
Damage type Weevil larvae feed on inside of young
vigorous shootsvigorous shoots
Micro-habitat(s) Terminal shoot
Does not kill tree
Although it occurs naturally in our forests, in eastern Canada, it is considered to be the most serious pest of white pine, jack pine and
Norway spruce plantations. The white pine weevil may significantly hinder the growth of young trees. Damage is caused mainly by the
larvae, which feed under the bark of the tree’s terminal leader. Feeding punctures made by the adult weevils can also damage the leader.
The presence of the insect is easily detected by the drooping, wilted appearance of the current year’s leader, which resembles a
shepherd’s crook. The leader is eventually killed. Symptoms are usually noticeable by late June.
Jack pine budworm
Micro-habitat(s) Needles
• Native to North America, the jack pine budworm was long confused with the spruce budworm, Choristoneura fumiferana (Clemens). It
was not until 1953 that the jack pine budworm was recognized as a separate species. This insect occurs throughout the range of its
principal host, jack pine. In Canada, it is found primarily in Ontario, Manitoba and Saskatchewan. In the United States, it also occurs in
the states bordering the Great Lakes. Jack pine budworm damage causes major economic losses in jack pine stands and Scots pine
plantations.
Exotic forest pests of conifers
• Balsam wooly adelgid
Micro-habitat(s) Branch, root collar, trunk, twig
Will kill tree if outbreak severe
The balsam woolly adelgid, a species introduced from Europe, was first reported in Canada in 1910, in southern Nova Scotia. The balsam
woolly adelgid causes two types of damage. Affected trunks can be recognized by the presence of the insect covered in white woolly
material in bark fissures, causing swelling of the affected areas and an increase in stem diameter. The second type of damage results from
the insects attacking the shoots. This causes swelling and distortion of the twigs, a syndrome commonly called "gout".
White pine blister rust
bush, limber pine, western white pine,
whitebark pine
Will kill tree
Although white pine blister rust fungus first attacks the needles, it is usually not noticed until it appears on the branches or trunk. In
mid-summer, orange pustules develop on the bole and exude a liquid containing spores. The following spring, these spores cause white
blisters to form on the bark. The white fruiting bodies give rise to a canker that keeps growing. The foliage above the canker yellows
and then turns reddish brown. The disease has a complex life history and cannot spread directly from pine to pine but must develop on
an intermediate host: the leaves of gooseberries or currants.
Brown Spruce Longhorn beetle
spruce, white
spruce, Norway
• Micro-habitat (s): Trunk
• Will kill tree
The brown spruce longhorn beetle (BSLB) is an invasive alien insect that infests red, white, black and Norway spruce trees. It was
introduced to Nova Scotia about 20 years ago and was positively identified in 1999. It It likely arrived in Halifax in wood packing
materials in container shipments from Europe. re-infests the tree every year until the tree dies, usually in 1–5 years. Unexplained resin
flow along the bark is a good indication of BSLB.
Native forest pests of hardwoods
• Forest tent caterpillar
• Whitemarked tussock moth
cherries, gray birch, mountain-ash,
aspen,
willowwillow
Tree will usually survive
A species native to North America, the forest tent caterpillar is the most widespread defoliator of deciduous trees. Its range extends from
coast to coast. Infestations are generally short and parasitoids are very important in the natural control of populations. The most
important parasitoid is the large flesh fly, Sarcophaga aldrichi Parker, which acts quickly after the start of an infestation, and can
destroy up to 80% of the pupal population.
Whitemarked tussock moth
Damage type Defoliation
Will kill tree
This native insect occurs periodically in large numbers. Primarily it is a pest of broad-leaved trees but, when numbers are high, it also
attacks coniferous species such as fir, spruce, and larch, and may cause severe damage to Christmas trees. The caterpillar is characterized by
a red head, two long black tufts of hair on each side of the head and one near its hind end, and four greyish brush-like tufts and two bright
red spots on its back.
Black knot
Native disease
(Genus Prunus)
Damage type twigs, baranches, trunk
• The name "black knot" aptly describes the most obvious sign of this disease: a rough black gall that can encircle the entire branch.
Infection occurs during the spring, but the symptoms do not appear until the following spring. At that time, the bark on affected
branches ruptures and a green liquid is expelled, and an olive-green swelling is formed. Over the summer, the gall turns a darker
colour, eventually becoming black and hard. While the older parts of the gall die subsequently, the fungus continues to grow both
around and along the affected branch. Large branches can resist the disease a long time after the infection begins, thereby
supplying spores that enable continued spread.
Damage type twigs, baranches, trunk
Will not usually kill tree
Exotic forest pests of hardwoods
Beech bark disease
Micro-habitat(s) Branch, trunkMicro-habitat(s) Branch, trunk
Will sometimes kill tree. Makes wood useless except for fuelwood
Beech bark disease is caused by the fungus ectria galligena, which is carried by two different scale insects,
Cryptococcus fagisuga and Xylococculus betulae. It is transmitted into the tree when the insect feeds with its
needle like mouthparts (beech scale link) The fungus kills the bark and cambium causing cankers which can
eventually lead to the death of whole branches and the entire tree. Around October small red reproductive organs
called perithicia can often be found making small circles on the bark of the infected tree.
Butternut canker
Exotic disease
under bark
roots
Will kill tree
The most obvious symptoms of butternut canker are the elongated, sunken cankers, which commonly originate at leaf scars, buds, or
wounds. In spring, an inky-black fluid exudes from cracks in the canker; in summer, the cankers appear as sooty black patches, often
with a whitish margin. Butternut canker was first described in Wisconsin in 1967 by Dr. James Kuntz. Butternut canker is currently
known to exist throughout the range in of butternut in Canada. It is the only New Brunswick tree species to be included on the
COSEWIC.
cambium layer under
the barkthe bark
Will kill tree
Dutch elm disease is a fungal disease of elm trees which is spread by the elm bark beetle. In an attempt to block the fungus from
spreading, the tree reacts by blocking the vascular tissue responsible to the translocation of water and nutrients. Although this is effective
in limiting the spread of the fungus it also contributes to the tree’s death. Although believed to be originally native to Asia, the disease has
been accidentally introduced into America and Europe, where it has devastated native populations of elms.
Gypsy moth
Exotic insect
Main host(s)
hemlock, gray birch, hickories, larch, pines,
poplar/aspen, red maple, red oak, spruce, sugar
maple, trembling aspen, white birch, white elm, willowmaple, trembling aspen, white birch, white elm, willow
Damage type Defoliation
Will kill tree
The gypsy moth is an invasive alien species that was accidentally introduced in North America in 1868. The female gypsy moth cannot
fly but movement of the population can be facilitated by humans who unknowingly transport egg masses from infested to non-infested
areas. There are over 300 known host plants for the gypsy moth. In North America, the long list of preferred hosts includes oak, cherry,
white birch, maple, alder, willow, elm and trembling aspen.
Emerald Ash Borer
ash,
• Micro-habitat (s): Trunk
• Will kill tree
The emerald ash borer is an exotic insect that was first identified in North America in 2002 near Detroit, Michigan and Windsor,
Ontario. Since then it has spread to over 13 U.S. states and the provinces of Ontario and Quebec. It has killed millions of ash trees and
poses a major economic and environmental threat to urban and forested areas in both countries.The emerald ash borer attacks and kills
all species of ash, except mountain ash which is not a true ash. With artificial spread, where people move infested ash materials and