Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00002409
11/12/99
PSEUDOTSUGA INSECT PROBLEMS
Aphids of various types may cause needle loss or twisted,
discolored needles. Honeydew produced by the insect may coat
lower parts of the plant or surrounding foliage. A black
fungus may grow on the honeydew. Predator insects often
bring aphid problems under control.
Bagworm lives in a two to three inch long sack built from
needles. The insect overwinters as an egg in the sacks of
the females. The injury consists of feeding on the foliage
with most of the injury near the top of the tree. Control by
hand-picking the bags in winter.
Cooley Spruce Gall Adelgid alternates between spruce and
Douglas-fir. On Douglas-fir, the insect cause the needle to
bend or curl. The affected needles will display yellow
spots. Look for the round, fuzzy insects on the needles.
Eastern Pine Shoot Borer caterpillars bore through the
center of shoots. The weakened shoots droop, curl or break
and turn yellow. Cutting the shoots lengthwise will expose a
sawdust-like material. Pesticides are not effective after
the injury is obvious. Chemical controls must be applied in
mid May.
Elongated white flecks on the needles may be Pine Needle
Scale. The insects suck juices from the foliage causing it
to become discolored. Heavy infestations will reduce tree
health. Dormant oil sprays in late fall or early spring will
control the problem.
Related information.
Pesticide Recommendations
Pine Needle Scale
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This file was generated from data base ZZ on 01/19/00.
Data base ZZ was last revised on 11/12/99.
For more information about this data base or its contents please contact
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