Page Contents:
5. Treatment Options
5.1
Colony Eradication
5.2
Managing the Risk of Infestation
5.2.1 Chemical Soil Barriers
5.2.2 Physical Barriers
5.2.3 Baiting
5.2.4 Building Maintenance Practice
5. Treatment Options
Termite treatments fall into two classes;
- Eradication of a current infestation
- Management of the risk of infestation (what
used to be called protection before the most effective termiticides
were banned)
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5.1 Colony Eradication
Around 1920 William Albert Flick (the founder of WA
Flick and Co) discovered, after a lot of trial and error, that a
compound of arsenic could be used to eradicate termite infestations. The
‘Flick’ arsenic trioxide dusting process was patented in the late
1930’s.
Since the 1920’s arsenic trioxide dust has been
used to successfully and safely eradicate termites from millions of
Australian homes and buildings.
A very small quantity (often less than one gram) of
the finely ground arsenic dust is applied to the live termite workers in
the galleries and tunnels that they make in the timber they are
infesting. This is done by making or drilling a small hole into the
damaged timber and with a hand puffer a small, almost invisible, amount
of arsenic dust is blown into the interior of the termite tunnels and
galleries. These dust injection points are made at 30 to 60cm intervals
along the affected timbers, ensuring that as many live termites and as
much of the interior of the tunnels and galleries are lightly coated
with the dust.
Much of the
success of this technique relies on the fact that arsenic trioxide is
not water soluble it is not absorbed through the termite’s skin.
Therefore after feeding on the infested timber, the termite workers as
normal return to the nest to feed other colony members and unwittingly
carry the arsenic dust into the heart of the nest on the outside of
their bodies. On returning to the nest, workers regurgitate the timber
they have eaten to feed the other colony members including the Queen. In
this process of regurgitation and re-feeding the arsenic dust
contaminates the food supply of the nest. The arsenic dust is also
passed on from one termite to another in the normal process of preening
and grooming between individual termites. The nest bound members of the
colony groom the workers retuning to the nest and ingest the arsenic
dust carried on the exterior of the treated termites.
As individual termites die they are eaten by their
fellow colony members. If the cause of death has been arsenic poisoning,
the cannibal termites die of the same arsenic particles because the
arsenic is not metabolized (changed) in the ingestion and subsequent
intoxication process.
Arsenic trioxide is a slow stomach poison; an
individual termite will usually die within a few hours of ingestion.
The whole termite colony will usually be destroyed
within 5 to 7 days of arsenic dusting of a termite infestation.
Termite feeding and therefore damage will generally stop within a
day or two of the arsenic dust application.
After an arsenic dust application the treated area
should be left undisturbed for 10 to 20 days. During this period the
pest control technician will return to assess the effectiveness of the
treatment. One treatment, using only a few grams of arsenic dust, is
usually sufficient to eliminate an infesting colony. However, depending
on the situation, sometimes several applications may be required to
achieve a total eradication.
This remote destruction of the colony by applying
dust to the termites in the building is very useful since it is almost
impossible to locate the position of the offending nest in environment
surrounding the building. While in most cases the nest is usually within
20m of the building, in some cases the nest could be up to 100m from the
building. The other advantage of the process is that only a small
section of the total colony needs to be discovered and treated, for the
entire colony to be destroyed.
In recent years in response to the perceived risks
associated with the use of arsenic trioxide dust, several new dust
compounds have been developed. These compounds fall into two broad
groups;
1. Insecticidal dust compounds in general are often
less effective because they tend to kill the termites too quickly,
resulting in insufficient treated termites returning to the nest for
translocation of a lethal dose to be successful. Research is on going
with good progress being made with an active ingredient called
fipronil, which is showing the
most promise. By design
modern insecticides tend to present relatively low risk to humans when
used according to label recommendations.
2. Insect Growth Regulators (IGRs) focus on the
characteristic of insect growth called moulting. For juvenile insects to
grow and develop they need to shed their old shell and form a larger new
shell; this is known a moulting. IGRs interfere with the formation and
hardening of the new shell, ultimately resulting in the death of the
individual. IGRs have little effect on adult insects since they do not
generally moult.
The use of IGR compounds to remotely destroy
termite colonies can be effective but it is by necessity a slow process
resulting in ongoing infestation for up to 6 months. The process needs
to take a long time and damage needs to continue in the building because
the adults need to feed and continue to carry the IGR back to the nest
to kill subsequent generations of juveniles. The treatment essentially
works by depriving the colony of replacement adults. Without younger
adults, the colony slowly becomes weaker and fades as the existing
adults become older, frailer and eventually die.
IGRs present the least risk to humans of all the
compounds currently used to eliminate termite colonies. On the other
hand the use of IGRs tends to be expensive because the high labour
content associated with the need for regular reapplication of the
treatment during the eradication phase.
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5.2 Managing the Risk of Infestation
Before embarking on a risk management program it is
important to first consider the cost-benefit equation.
What do I stand to loose if my building becomes infested (i.e.
the cost of eradication and repair)? What will it cost over time to
reduce the risk of termite infestation (i.e. the cost of treatment
applications, inspections, booster treatments etc)?
If we assume termites infested every house once
every 10 years (I think it is more likely once every 25 years on
average) and it costs $5000 to eradicate the infestation and repair the
damage, then the average annual cost would be about $500 per year.
By my figuring $500 per year is the break even point for
investing in a termite risk management system that is 100% reliable.
Unfortunately risk management systems currently
available are far from 100% reliable. Once you have done your research
you should ask three pest control companies to provide written quotes on
the same risk management system (so you are comparing apples with
apples). You must then take the time to read the small print
associated with each written quote. As the saying goes “the devil is in
the detail”.
Regard anyone who claims 100% effectiveness of
their system with suspicion.
Be aware that a “5 year guarantee” offer by the
pest control industry does not mean you will not get termites in your
building for 5 years. It means that if your building does become
infested the company will come and eradicate the infestation, usually
free of charge. You will still have to bear the cost of repairs and the
emotional trauma.
Yes, termite risk management systems can reduce the
risk of termites infesting most buildings. The question then is, “Is it
economically viable”?
Over the years I have come to the conclusion that
termites have much more of a psychological impact on people than the
economic impact associated with the cost of treatment and repair. To put
it another way “termites mess with people’s minds more than they mess
with their homes”.
The unethical termite treatment salesman knows this
too and is not adverse to play up the fear factor to achieve his sales
targets. As a buyer of termite treatment services be informed and be
aware.
There are four approaches to managing the risk of
infestation in a building. These may be used individually or in varying
combinations.
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5.2.1. Chemical
Soil Barriers:
Chemical soil barriers are formed by mixing an
insecticide in the soil around and/or under a building so as to isolate
the building from the surrounding environment. This treated soil barrier
is designed to stop termites that are foraging in the yard and the
general environment from accessing the building.
Pros: Chemical soil barriers can reduce (but
not eliminate) the risk of termite attack on the building.
Cons: Chemical soil barriers are very
difficult to apply to achieve an effective, long lasting barrier. The
more complex the structure of the foundation of the building the more
difficult is the job of forming a chemical soil barrier. One of the
limitations of modern insecticides is their general immobility in the
soil (by design). This immobility means that it is difficult to mix them
into the soil by pressure injection. Another limitation is their
biodegradable nature (by design). Since the insecticide products are
generally very biodegradable, chemical soil barriers can degrade very
quickly. Long term residual is often only achieved by mixing the
insecticide into the soil at very high concentrations. As a result of
these limiting attributes, formation of effective chemical soil barriers
is a difficult and time consuming task. This translates into chemical
soil barriers being very expensive to install and maintain.
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5.2.2. Physical Barriers:
Physical
barriers, such as ant capping, are generally designed to force termites
to show themselves as they gain access to the building. For example the
ant capping on top of a timber stump is designed to force the termites
to build a mud pack to get around the ant cap and therefore make their
presence more obvious during regular inspections.
Pros: Depending on the material used
physical barriers can be very long lasting and often require no ongoing
maintenance or reapplication.
Cons:
While the installation of
physical barriers around penetrations (posts, pipes and conduits)
through concrete slabs can prevent termite ingress, generally physically
barriers are not preventive or risk reducing per se but are design to
serve as an aid to inspections. Physical barriers need to be inspected
regularly and carefully if they are being relied upon for risk
reduction. Generally it is difficult if not impossible to fit effective
physical barriers to existing buildings. Physical barriers can be
easily damaged or compromised by other trades during construction or
subsequent building and maintenance activities.
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5.2.3. Baiting:
Since termite infestations in buildings arise from
termite nests in the surrounding environment, it seems to make sense to
destroy those nests before they become a problem.
Termite baiting involves the placement in or on the
ground, containers (bait stations) filled with termite food material
(wood, wood shavings, cardboard etc). Over time (months and sometime
years) a termite colony will find the bait station during its normal
forging and begin to feed on the material. When feeding is well
establish the pest control technician will introduce either an
insecticidal dust or an IGR as discussed above in the section on colony
eradication.
None of the currently available bait systems use
pre-treated baiting material. All rely on the ‘insecticide’ being
applied to those stations found during regular inspection to have
termites actively feeding.
This technique can also be used to treat a termite
infestation in a building and may be particularly useful in a situation
where there is not enough termite activity to use a direct application.
Pros: Termite baiting can successfully
eradicate termite colonies. Where there are only a few termite nests
within striking distance of the building, baiting may be effective in
reducing the risk of termite attack on the building.
Cons:
In tropical and sub-tropical environment where
there are often up to a few dozen termite colonies within striking
distance of the building, killing a few termite nest would seen to offer
very little risk reduction benefits.
It is a bit like trapping flies in the outback during summer; yes
you trap a lot of flies, but the population is so large that you can not
trap enough to make a difference.
Termite baiting is very labour intensive resulting
in programs costing thousands of dollars per year.
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5.2.4. Building Maintenance Practice:
There is a lot the average home owner can do to
reduce the risk of termite attack, much of it is common sense when you
think about it.
There are a multitude of activities that can make a
difference and each building will have it own unique set of must do
tasks. That means each building owner needs to think creatively and even
engage a professional termite company to make suggestions about things
that can be done to discourage termites activity close to the building,
to make it more difficult for termites to enter the building unnoticed
and to make the building more easily and effectively inspected.
The task should focus on the following goals;
- Reduce the availability of water and wet areas
in and around the building (e.g. fix leaks, improve drainage,
improve ventilation etc.)
- Reduce the availability of timber and timber
by-products from in and around the building (e.g. remove or restore
fire wood and building materials, remove heavily timber mulched
gardens from around building etc.)
- Improve the physical isolation of the building
from the surrounding environment (e.g. trim timbers connecting the
building with the ground, reduce soil height around the building,
expose concrete footings etc.)
- Improve access for inspection (e.g. store
materials in the middle of the store room so you have clear access
to walls for inspections, trim back vegetation around and on the
exterior of the building, open access in to sealed spaces etc.)
Pros: Mostly low cost activities with little
on going costs. Often this approach involves simply reorganising and/or
rescheduling normal maintenance activities.
Cons: Requires an ongoing commitment on
behalf of the building owner to take responsibility for the regular
maintenance and inspection of their home. Often once the initial panic
associated with termite discovery has subsided, building owners are
inclined to loose focus (it is human nature). The message is to remain
“alert but not alarmed”. Schedule regular reviews, say once every three
months (at the start of every season) and forget about termites in
between. That way you don’t burn out your enthusiasm and commitment.
Generally very little termite damage will happen from one three month
period to the next.
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