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THEY REALLY BUG ME...Mountain Pine Beetles - Just the Facts!
By Nancy Tamura
What
are Mountain Pine Beetles? What do they do, and what should I do? And, why
should I care? The answers to these questions are obvious to those of you
who are long term residents of the
Colorado
Mountains.
For those of us who are transplants, however, this information is new, vital
to our neighborhood and is pretty important - so please keep reading.
What Are Mountain Pine
Beetles?
Mountain pine beetles (Dendroctonus
ponderosae - killers of ponderosas are small (less than 1/4 inch long)
members of the bark beetle family. Except for a few days in July or August
when the adults emerge and attack new trees, they complete their entire life
cycle under the bark of certain pine trees, i.e. Ponderosas, killing the
tree in the process. The beetles are endemic to our forest but are usually
present in small enough numbers that they affect only those trees that are
under stress. However, as beetle populations increase, they begin attacking
most trees in the area creating an epidemic - that is what is happening now
in the state of
Colorado. Although
significant incidences of mountain pine beetles have not been identified in
Pine Brook Hills to
date, our neighbors in Boulder Heights and in Nederland are experiencing
outbreaks.
What
Do they do?
It is important to note that
when beetles successfully attack a tree,
that tree will not survive,
even though it will remain green for several months. In July or August, the
adult beetles emerge from their resident trees to find new trees to attack.
The unmated female beetles select new trees and emit phero- mones to attract
other beetles so that a mass attack can be launched against the trees. They
generally select larger trees that can provide adequate food to sustain them
through their life cycle (that's about one year here in Colorado), and they
bore into the lower fifteen: feet of the trees.
Following this, each mated
female beetle constructs a straight verti- cal path averaging about 10
inches just under the bark on the trunk of the tree and lays approximately
75 eggs. When the larvae hatch, they create their own tunnels at about right
angles to the original tunnel.
They become pupae in June
and July and grow to adults who will begin the new cycle. Beetles usually do
not travel more than a mile to attack a new tree, but Steve Grube from Hayes
Tree Service says that "one beetle tree within five miles of you can cause
you trouble.''
In addition to the damage
the beetles themselves do to the tree, they carry bluestain fungus (Ceratocystis
species) on their bodies which attacks the woody part of the tree. This
combination of beetle feeding and fungus interrupts the flow of water in the
tree and rapidly kills it.
Have
They Attacked My Trees?
The obvious way you can tell
if the beetles have attacked your trees is that they turn brown and die.
However, by this time it is too late to do anything about destroying the
beetles because they have already left the tree.
The best solution to
identifying beetles presence is to walk around your property and look at
your trees. When the beetles bore into the bark, the trees emit pitch in
popcorn-size balls. If the tree is successful in repelling the beetle
attack, the pitch will be cream- colored - the beetles actually drown in the
pitch and die. However, if the beetles have been successful, the pitch will
be a reddish color because it will have bark mixed in with it. Additionally,
you will see reddish boring dust in the cracks of the bark and at the base
of the tree. If you see this and suspect there are beetles, you should take
an ax and remove a large piece of bark off the tree (about 10 inches by 6
inches).
It will be immediately
apparent when you remove this bark because you will see the characteristic
tunnel structures and may see the beetles in some stage of their life
cycles. Also, at this time of year, the tree may be turning a light green,
and you may notice woodpeckers routinely feeding at the tree.
Taking the time now to
survey your property will allow time for you to determine a plan of action
to eradicate the beetles before they swarm (leave the tree) in July or
August.
What
Should I Do if I Have Pine Beetles?
The Colorado State Forest
Service recommends one of the following four ways to treat pine beetle
infested trees.
Solar Treatment with
Plastic: As early
as possible, but at least two months before the beetles emerge (mid-July
through August), cut down and delimb the infested tree (remember the beetles
live only in the trunk, not the limbs). Cut the tree into firewood-size
pieces (about two feet long, and split lengthwise) and stack the pieces no
more than two logs high is a sunny location. Wet the logs and cover with
clear (not black) plastic, less than 1/4". Seal the edges as well as
possible with available soil, and repair any tears with duct tape. Success
of this process depends on raising the temperature of the logs and
increasing the humidity so that mold canb grow beneath the bark. This
enviorment deters and/or prevents normal beetle development.
Debark:
Cut down the infested tree and remove all bark. Leave the tree and the bark
exposed to the sun. The beetles can not live and mature under this
condition.
Burn Infested Wood:
Cut down the infested tree and cut into firewood-size pieces. Burn in your
fireplace or wood stove along with your normal dry wood. All of the wood
must be burned prior to beetle emergence for this to be effective.
Remove from Area:
Cut down infested trees and haul them or have them hauled to an area which
is far away and does not contain other target trees. Hayes Tree Service
indicates they will haul the trees to a local landfill site where the trees
are buried.
Professional help is readily
available through local tree service firms such as Hayes or Boulder Tree.
How
Can I Prevent Pine Beetle Attacks on My trees?
Steve Grube says "the most
important thing is to pick out trees that are important to you and treat
them preventatively." This is done by applying a chemical called Sevin (or
Carbaryl) to your high value trees before the beetles fly in July or August.
Although some homeowners prefer to spray their own trees, tree service firms
are well equipped to do this for you.
Why
Do I Care?
We do not want to become a
case of history repeating itself. These beetles are deadly to our ponderosas
and can wipe out millions of trees in a single season. We would like to be
proactive in beetle management and if we act now, and in unison, to locate
affected trees we can insure that Pine Brook is not part of the pine beetle
epidemic which is occurring in other parts of the state.
Further information
regarding what our Homeowners Association is doing to assist you is
discussed in a separate article.
from The Pine Brook
Press, Spring 1998 |
