Integrated Pest Management for Christmas Tree Production: A ...

STEP 2. Identifi cation and
Understanding of Pests and
Problems
After the Christmas tree block is planted,
the focus of an IPM approach will be on
preventing losses due to pest damage. The
term “pest” may include any organism—
diseases, insects, mites, nematodes, mammals,
birds, or weeds—that is detrimental
to the health of the tree. Environmental
factors such as air pollution may also cause
damage. Knowing which pest or what factor
is causing damage to a tree is essential to
fi nding a means of stopping or controlling
that problem.
Insects and Mites
The largest groups of Christmas tree pests
are two classes of arthropod pests, or organisms
with jointed body parts and an exoskeleton.
These two classes are the insects
and the arachnids. Arachnids include mites,
spiders, and ticks, but only the mites can
be detrimental to tree health. Experienced
growers are familiar with the insect and
mite pests that may affect their trees. They
have, or know where to fi nd, information
about the life cycle and habits of these pests
in order to determine the best method and
timing for both detection and control, if
necessary (Fig. 2).
For example, spider mites (Fig. 3) and
(eriophyid) rust mites feed openly on tree
foliage without any extra protection. It is
easier to control these pests than one that
spends most of its life covered by a protective
coating, such as pine needle scale. In
addition to the mites, pests that feed openly
include aphids, gypsy moths, and sawfl ies.
The larger group of insect and mite pests
includes those that are only exposed for a
short time during their life cycle. Timing
sprays to target susceptible life stages is critical
for effective control. Pests that fall into
this category include all the scale insects,
most adelgids, bagworm (Fig. 4), weevils,
bark beetles, and midges.
Knowing these and other insects is essential
for growers to protect their trees from
pest infestation. In addition, recognizing
which insects and mites are benefi cial and
taking steps to avoid killing these organisms
can limit or even eliminate the need for
chemical control measures.
Stinging insects, such as wasps and bees,
are also a major concern on Christmas tree
farms, especially during summer mowing
and fi eld maintenance. These insects are
frequently attracted to trees infested with
aphids and scale insects. Recognizing both
the pest and the stinging insects and understanding
their biology are important when
considering employee safety.
Figure 2. Balsam twig aphid life cycle. Courtesy of Sarah Pickel, PDA (photos courtesy of PDA)
Figure 3. Spruce spider mite
feeding openly on tree foliage.
Courtesy of Rayanne D. Lehman,
PDA
Figure 4. Protective casing
containing bagworms. Courtesy
of Rayanne D. Lehman, PDA
IPM BASICS .............................................................................................................................................................................................................................................................................................. 7