Note: Many of these photographs are magnified, as the majority of the insects and their eggs are no larger than the head of a pin.
There are multiple images provided for your viewing: a smaller .gif version and a higher resolution, magnifed .jpeg version. You can access the .jpeg version by clicking on the smaller .gif view.
| Balsam Twig Aphids (Mindarus abietinus) |
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| The black balsam twig aphid egg is shaped like
a teardrop and covered with white waxy rods. Eggs like
this one can be found anywhere on the tree, although
they are common in new growth. Eggs are present from
June until they hatch in March or April. |
Once hatched, the green aphids feed on the underside
of needles. At bud break, they move into the opening
buds. They also feed on immature cones. The aphids, some
of which have wings, are common from March to June. |
Needles damaged by balsam twig aphids will curl
permanently if the damage is severe. If it is not, sufficient
rainfall and nutrients will straighten many needles. |
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Cinara Aphids (Cinara sp.
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Spruce Spider Mite (Oligonychus ununguis)
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| These large, dark brown aphids feed on shoots and
terminals in the spring. Their feeding activities commonly
cause a black fungus called sooty mold to grow on the tree.
Heavy infestation can result in stunted, chlorotic (yellowed)
growth. |
Adult spruce spider mites are dark red and have
eight legs. They are seen in warm, dry, sunny weather
feeding on new growth. To detect mites before damage
occurs, use a hand lens and check current growth. |
As the spruce spider mite feeds on Fraser fir,
it damages the needles with its piercing, sucking mouth.
The needles become speckled, spotted, or dusty. They
turn yellow, then brown, before they die and fall from
the tree. |
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Balsam woolly Adelgid (Aphid) (Adelges piceae)
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| If the top of a Fraser fir appears flat or crooked,
it may have balsam woolly adelgid damage. Look for easy-to-spot
crooked tops after new growth hardens. Other symptoms
include dead shoots, stunted growth, and stiff trunks. |
At harvest, look for red compression wood in the
butt of the tree. Balsam woolly adelgid feeding causes
the tree to form hard, brittle wood. Because the hard
wood can no longer carry water and nutrients throught
the tree, the tree eventually loses its needles and dies. |
If symptoms of the balsam woolly adelgid are observed,
check the tree's trunk and trunk-branch union for white,
woolly spots. These spots are the waxy coverings of adult
adelgids. They can be seen on the tree year-round. |
This small, dark purple female lays eggs on the
tree. Its feeding tube is permanently fixed in the tree's
bark. |
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Rosette Bud Mites (Tricetacus sp.)
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Root Aphids (Prociphilus americanus)
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White Grubs (Phyllophaga anxia, P. fusca, and Polyphylla
comes)
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| Because rosette buds are larger, hollow, and more
rounded than normal buds, they are easily filled with
hundreds of microscopic, eriophyid mites. As a result,
rosette buds either do not break in the spring or break
to form multiple, weakened shoots. |
Although root aphids feed on large roots, their
feeding causes no damage. They are often associated with
ants, which feed on the honeydew of the aphids. The ants
create tunnels and galleries to reach the aphids, thus
loosening the soil and sometimes damaging the trees. |
White grubs are the larva of scarab beetles. The
grubs live in the soil and eat roots for two to three
years before emerging as adult beetles. Adults lay eggs
in short grass in May and June. White grubs are associated
with pastures and will damage the roots of trees planted
on these sites. Look for grubs in summer and fall by
digging and sifting the soil. |
