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

Disadvantages:
1. Oils must come in contact with the
targeted pest to be effective.
2. Field conditions and weather during
applications may limit effi cacy.
3. Eggs will only be controlled if they are
present before the oil application.
4. Oil has no residual effect.
Cautions:
1. When temperatures are below freezing,
oil can cause phototoxicity. Under
these conditions, the oil and water cannot
stay mixed and the water freezes,
allowing oil droplets to accumulate.
When thawing does occur, the water
will evaporate, concentrating the oil on
plant surfaces.
2. Oil can also cause phototoxicity when
temperatures are above 90°F. Burning is
also a concern on the sunny side of the
trees or during times of drought.
3. Apply oils when conditions allow for
prompt drying; be sure to avoid drift or
overspray.
4. Mistaken dormancy is a problem in
early fall or late spring. In early fall, if
the plant is not in dormancy and the
leaves are water defi cient, then the oil
will burn the foliage. In late spring, new
growth is burned if the dormant period
ends before the oil is applied.
5. Conifers known to be sensitive to
dormant oils include Douglas-fi r and
spruce. Be sure not to spray oil on
glaucous, or blue, varieties of conifers
because the blue color will be removed
and may not return for 2–3 years.
Genetic variability may affect individual
plants differently, even if the variety
is known to be tolerant to oil.
When using oil, as with any pesticide,
be sure to follow label directions. Some
oils can be mixed with other pesticides to
increase the level of toxicity. Never mix
oils with dimethoate or any type of sulfur,
as serious phytotoxic reactions will result.
Most fungicides are not compatible with
oils. Always consult the oil and insecticide
labels for compatibility. Always choose
“superior-type” oils to provide further
insurance that these products are safe.
TRADITIONAL
This largest group of pesticides includes
insecticides, miticides, fungicides, and
herbicides. They can be the most effective
materials available to prevent and destroy
pests; however, they are frequently used
when other options are available. For many
years, broad-spectrum insecticides were the
only tools available to growers. In recent
years, newer, soft materials targeting specifi c
groups of pests have been introduced. These
materials are less likely to disrupt natural
enemies while keeping the target pest in
check.
The use of traditional pesticides should
always be a last resort. If a traditional
pesticide application is a must, choose the
right product, time, and dosage to avoid
problems. Inappropriate use may rid the
area of pests now, but it may also cause a
more serious problem later as pests become
resistant and natural enemies are depleted.
For maximum benefi t and to avoid hazards,
choose formulations that pose the least
threat to nontarget species. Be sure to rotate
classes of pesticides to decrease the chances
of pests developing resistance. Always read
the label before using any pesticide product.
IPM BASICS ............................................................................................................................................................................................................................................................................................ 15