Borates and The Facts About Wood

2. Borates and the Facts
About Wood
THIS COURSE WILL COVER THE BASICS OF
BORON, MARGIN OF SAFETY, USING BORN
TO CONTROL WOOD DESTROYING PESTS
INCLUDING SUBTERRANEAN TERMITES,
DRYWOOD TERMITES, POWDER POST
BEETLES, FUNGI AND TYPES OF WOOD.

3. Assured Control with
a Margin of Safety
• Borates are naturally-occurring
insecticides and fungicides. In
fact, products formulated from
borates, cannot be synthesized
or manufactured like
conventional pesticides. Instead,
borate insecticides and
fungicides are derived from
scarce mineral deposits found
chiefly in the western United
States. Boron is one of the 109
elements on the chemist's
Periodic Table of Elements.

4. Too reactive to exist in its pure form in nature, boron is
found in mineral deposits as a crystalline group of
"borates" (oxides of boron), that include boric acid, borax
and others.
As one the Earth’s elements, it is not surprising that
small amounts of boron, in the form of borates, are
found in the soil, sea, plants and animals.
Borates in Nature

5. ➢ All the roles that borates play in nature have not been
discovered. However, biologists know that borates are an
essential micronutrient for plant life and also play an important
nutritional role in animal life.
► Researchers are currently trying to determine if borates play
an essential role in human life.
What Roles Do Borates Play in Nature

6. Borate use
in Pest
Control
► When and how borates were first used in pest
control is not documented. It is possible that
borate miners in the 1800s may have
discovered that they did not suffer from the
flea and lice infestations so common at the
time. What is known is that borates have been
used for more than 100 years to control pests.
► One advertisement from the 1880s promoted
a formulated borate cockroach bait product.
By the 1940s borate formulations were being
used to protect wood. Because they are
water-soluble, borates will diffuse into wood
using the wood's own moisture.

7. Borate use
in Pest
Control
► Once diffused into the wood, borates protect
against termites, wood destroying beetles,
carpenter ants, fungi and other wood
destroying organisms. This protection can last
for decades because borates are inorganic
compounds that do not break-down boron
was introduced in the United States in 1991 by
U.S. Borax, the world leader in borate
technology.
► The product's introduction into the United
States follows more than 40 years of
successful use to protect wood in Europe,
Australia and New Zealand.

8. Boron has a
proven
Mode of
Action
Over time, inhibition of fundamental biochemical
activity results in death. Because the mode of
action is fundamental, borate efficacy is absolute
and effective against a broad spectrum of pests.
Importantly, this fundamental mode of action
also means that development of insect resistance
to borates is virtually impossible.
Borates have long been known to be slow-acting
stomach poisons to insects and a contact poison
to wood destroying fungi. Borates are not directly
lethal to an organism. Rather, they inhibit
necessary oxidative metabolic activity at the
cellular level - a constant energy-producing
process necessary for life.

9. Human
Margin of
Safety
While highly effective against insects
and fungi, borates provide a significant
margin of safety for humans.
While the mode of action is the same
for all living cells, human exposure to
borates from pest control applications
simply does not pose a significant risk
for several reasons:

10. Human
Margin of
Safety
Human exposure levels from pest control
applications are insignificant in comparison to
insect dosage levels because humans are
physically so many times larger than insects.
Borate exposure is further limited in humans
because of the way human bodies efficiently
eliminate borates. In humans, any elevated
exposure to borates is rapidly processed by the
kidneys and eliminated through urination.
Chronic borate exposure is limited because
borates do not bioaccumulate in humans or
other mammals.

11. Human
Margin of
Safety
Borate exposure is limited because borates are
not absorbed through intact skin.
Borate mammalian toxicity is relatively low.
Disodium octaborate tetrahydrate has an acute
oral LD50 of 2,550 mg/kg in rats, an acute
dermal LD50 of greater than 2,000 mg/kg in
rabbits, and an acute inhalation toxicity (LC50)
of 2.0 mg/h in rats.

12. Borates in Commercial and
Industrial Applications
• Borate chemical properties are used in many
commercial and industrial applications.
• Borates are used in the production of products as
diverse as detergents, cosmetics, medicines,
flame retardants, hydraulic fluids, fiberglass
insulation, microelectronics, fertilizers, ceramics
and glass.

13. Borate insecticides provide a margin of safety for humans
but are lethal to insects because insects are exposed to a
much greater dose in relation to their body size and weight.
The primary exposure route for insects - ingestion from
eating treated wood or by grooming -provides a lethal dose,
and insects can also be exposed through direct contact and
absorption through their body wall.

14. Effects of Borates on Organisms
• Once ingested, insects cannot eliminate borates from their bodies in the
way humans can.
Borates are a contact poison to wood destroying fungi. The mode of action
is the same as with insects, but fungi do not ingest the borates like insects.
Instead, a treated wood environment puts fungi constantly and directly in
contact with the lethal borate.

15. Borate
environmental
profile
► Borate use in pest control poses a low risk
to the environment. While an essential
micronutrient to plants, an excessive
dosage of borates can be phytotoxic to
trees, shrubs and other plants around or
in a structure.
► If a borate solution is accidentally sprayed
on plants, the plants and surrounding
area should be washed down with plenty
of water to dilute the borates.

16. BORATES HAVE A LOW
TOXICITY TO FISH.
THE LC50 FOR TROUT IS 350
ML/L.
HOWEVER, CARE MUST BE
TAKEN TO KEEP BORON
APPLICATIONS OR OVERSPRAY
FROM ANY BODY OF WATER.
BORATE APPLICATIONS TO
WOOD DO NOT RESULT IN
AIRBORNE RESIDUES.

17. Using Boron to
Control Wood-
Destroying
Organisms
► In the past, different pesticide formulations
and active ingredients have been used for
control of wood-destroying organisms
(WDOs), beetles, decay fungi and termites
above ground. These products often
presented problems. Some had strong
odors, none penetrated wood well and the
effective residual life was short.

18. Borates on Wood
• Fumigation, while still required
in many cases, is expensive and
provides no residual protection
against reinfestation.
• Boron Insecticide is a product
that can effectively solve many
of these problems. It is easy to
mix and apply and has no odor.
• Its residual life is indefinite if
the treated wood is protected
from running water.

19. Borates on
Wood
• Boron penetrates far better than do other
residual insecticides used to control wood-
boring insects.
• In order to understand the potential for
attack on wood by insects and fungi, it is
necessary to become familiar with the
relative importance of the specific classes
and parts of wood, and the moisture in the
wood.
• This understanding will also provide
information on how boron penetrates
wood.

20. Two types
of wood
There are two types of
wood: hardwoods and softwoods.
Hardwoods come from trees that
have leaves: oaks, maples or
walnut, etc.
Softwoods come from trees
having needles: the pines, firs and
spruces.

21. Wood
Under The
Bark
When alive, the wood directly under the bark
that is involved in the movement of sap is called
sapwood. The wood in the center of the tree is
often darker in color, and is called heartwood.
Generally the sapwood and early wood are the
target of insect attack. Stored products in wood
cells attract beetles and termites attack early
wood.
Heartwood, however, has stopped functioning in
the movement of sap, and has had a number of
substances deposited in it, which also impart
resistance to attack by insects and decay fungi. It
is often more resistant to the movement of
water and is more difficult to penetrate with
insecticides.

22. Wood moisture levels
• When freshly cut logs are processed into usable
lengths of wood, the wood then used in
construction is kiln dried, having moisture levels
of 15% or less.
• However, while wood is in storage or after it is in
use, it slowly reacts to the moisture in the air
around it and assumes equilibrium moisture.

23. A. CAMBIUM -
LIVING CELLS
THAT FORM
NEW WOOD
B. OUTER BARK -
DEAD,
PROTECTIVE
LAYER
C. INNER BARK -
LIVING:
TRANSPORTS
FOOD FROM
THE LEAVES
D. SAPWOOD -
LIVING AND
DEAD CELLS:
TRANSPORTS
SAP AND
STORES FOOD
E. HEARTWOOD
- INACTIVE,
DEAD CELLS
CONTAINING
EXTRACTIVES
F. PITH -
SPONGY
CENTER OF
ORIGINAL STEM
G. WOOD RAY -
CELLS WHICH
MOVE SAP
ACROSS THE
GRAIN
H. ANNUAL
GROWTH RING
- EARLY - AND
LATEWOOD
PRODUCED IN
ONE YEAR

24. Moisture Levels in
Wood
• There are many factors that influence the final
moisture level reached.
• Also, within structures the levels may vary
during the year.
• Such things as ventilation, drainage, heating
and air conditioning, humidity and
condensation, etc., influence moisture
content of the building and, therefore, of its
wood.
• In addition, wood-boring organisms attacking
structural wood are often dependent on
relatively high moisture contents to initiate
attack and in some cases, to continue their
attack on the wood.

25. Termites will attack "dry" wood but bring
moisture into the wood. Wood decay fungi
need even higher moisture contents to begin
their attack. That will continue as the wood
becomes wetter until the cell cavities are
filled with water.
► The moisture needs of these
organisms are important to
understand, since the wood moisture
content will affect the rate and depth
to which boron will diffuse into wood.
At low moisture contents, some
diffusion will occur, but surface
amounts of borate are extremely high.
However, treating wood with a high
moisture content means that boron
will diffuse deeply into the wood to
protect against or eliminate WDOs.

26. Subterranean termites
► While destroying wood, termites also increase
the moisture content of wood in which they are
feeding.
► In some instances, subterranean termites may
find a moisture source above ground and
survive without any contact with the soil.
► The picture on the right show a drop tube from
termites in a ceiling.
► Notice the small stain on the ceiling.

27. Subterranean
termites
Subterranean termites, the insect that causes the
greatest amount of damage to structural wood in
the U.S., will damage both hardwoods and
softwoods.
It is typical of subterranean termites to consume
the softer early wood first, leaving the layered
appearance in the damaged wood
The initial damage begins on the wood surface,
but termites can tunnel and produce galleries
throughout the wood.
In larger dimensioned timbers, these tunnels or
galleries can penetrate deeply into the wood.

28. Treatment of
Wood for
Termites
In these cases, the usual soil treatment will not solve
the problem, or control can be delayed for months.
Locating and eliminating the moisture source is
critical for control. Even if the termites are controlled
by treatment, wood decay can take over and
continue to destroy any of the wet wood.
Termites enter the wood from the surface, so the first
target treatment area for application is the surface. If
an infestation is already present in the wood, the
higher moisture content should increase the
movement of the boron.
Boron treatment will control both termites and wood
decay even when alternative moisture sources are
available. However, elimination of the moisture
source is recommended in any case.

29. Drywood termites
► Drywood termites feed internally in both hardwoods and
softwoods and can survive in wood that is quite dry (3%).
► Again, these insects enter from the surface so even
though the wood they attack is fairly dry, boron on the
surface will prevent initial attack.
► In established infestations, Boron can be injected into the
termite galleries or the wood itself to obtain control.

30. Dampwood
Termites
► Dampwood termites require no
ground contact, but attack wood
with a high moisture content and
often coexist with wood decay.
► These termites can be controlled by
spraying or brushing wood with
boron because the high moisture
level in the wood enhances Boron
penetration.

31. Powderpost
beetles
► There are two types of
powderpost beetle
that attack wood in
structures. The lyctid
powderpost beetle,
sometimes called true
powderpost beetle,
will attack the
earlywood of certain
hardwoods. Their eggs
are laid in rather large
pores (wood cells) in
the earlywood and the
larvae tunnel directly
into the surrounding
wood.
► This means that their
attack will usually be
rather scattered and
damage is restricted
to particular parts of
the wood.
► As the larvae
complete
development and
prepare for
emergence as adult
beetles to the
outside, they tunnel
close to the surface
of the wood

32. ► Lyctids may attack wood that is
quite dry but a surface Boron
treatment will deposit high
amounts of borate and thereby
prevent initial attack and kill any
larvae feeding just beneath the
surface.

33. The other type of
powderpost beetle, the
anobiid, will attack both
hardwoods and
softwoods that have
higher moisture content
than normal. There is
variation among the
anobiid species, but they
tend to be problems
primarily in damp,
poorly ventilated crawl
spaces.
Applications of Boron protect the surface of the
wood and stop larvae from entering the surface
of the wood. The higher moisture level enables
the borate to penetrate and kill larvae in the
wood.
The eggs are laid on the wood surface and the
larvae bore directly into the wood. They usually
tunnel within the sapwood and only
occasionally into heartwood. As the larvae
mature, they also tunnel back to the surface in
preparation for the emergence as adults.

34. Old house
borers
► Old house borers are found in the sapwood of
softwoods.
► The eggs are laid in cracks in the wood surface
and the larvae bore into the wood below.
► The old house borer only requires 10%
moisture to infest wood, so they may be found
in wood in drier parts of buildings.
► They may bore deeply within large timbers,
but frequently they tunnel quite near the
surface. Again, surface treatment with boron
will stop initial infestation and kill larvae
tunneling near the surface.

35. Carpenter
ants
Carpenter ants construct nests in hardwoods
and softwoods, but do not consume the
excavated wood.
Though they usually start their nests in damp
wood, they can extend their galleries into dry
areas.
In addition, they sometimes form satellite nests
in wood that is no wetter than the surrounding
structural members.
Because of their habit of moving from outdoor
infestations to indoor locations, they crawl over
wood surfaces that they have not attacked.

36. Carpenter
ants
This makes them susceptible to picking up
boron dust that has been applied outside their
nest galleries.
As they groom themselves, they take
insecticide into their stomachs and are
poisoned.
In addition, since they often start their attack
on the wood surface, boron solution
applications to the surface have proven very
effective at preventing carpenter ant
penetration.

37. Decay fungi
► The common Brown and White rot fungi
require wood moisture of 25% or more to
maintain an infestation and to destroy the
wood. Their destruction is internal and
only in later stages of development will
you see the fungus growing on the wood
surface.
► Boron is a contact poison to these
organisms. Surface treatments will protect
the wood against attack. If already under
attack, the high moisture will allow the
boron to penetrate deeply into the wood,
to the source of the problem.
► (One strain of fungi, Poria Incrassata has
water-conducting strands that carry water
from soil into building elements.)

38. White Rot
Brown Rot
Poria Incrassata

39. Wood Facts and
Fictions
► Dry rot.
► There really is no such thing as dry
rot.
► Wood needs 4 things to decay
► water
► oxygen
► food (wood)
► favorable temperature (40F - 105F).
► Keep wood below 22% MC and you are
generally safe.

40. Rot is
catchy.
Only when conditions are right will the infection
develop into rot. The moisture content (MC) of
wood needs to be above 28% to be initially
infected.
Since all lumber is above 28% MC at some point
in its life, all lumber is infected.
When the MC of wood drops below 22% the rot
fungi goes dormant. It’s harmless, but it will be
reactivated when the MC rises above 22%.
The solution is: keep wood dry or treat it with
Boron.

41. Pressure
treated lumber
is resistant to
attack by
termites and
carpenter ants.
This assumption is half true. Termites that
eat treated lumber will die. However,
termites may also decide to tube around CCA
(Chromated copper arsenate) treated wood
and survive to enjoy the more delicate studs
and joists that lay beyond the poisoned
barrier.
Arsenical treatments do not repel or kill
carpenter ants. (In 2003 the EPA and the
lumber industry agreed to discontinue the
use of CCA treated wood.)

42. Pressure
treated lumber
is resistant to
attack by
termites and
carpenter ants.
► Ants are attracted to wet and decayed
wood because it is soft and weak. It is easy
to chew. That’s why ants like foam
insulation. Ants don’t ingest wood, they
simply hollow out wood and nest in it.
Wood that is treated with borates is a
different story.
► Borates are very soluble and can be picked
up by ants as they work their way through
borate-treated wood. The borates are
ingested when ants groom themselves.
They are then poisoned at this point.

44. ► The use of trade names in this publication is solely for the purpose of
providing specific information. American Pest CEUS does not
guarantee or warranty the products named, and references to them
in this publication do not signify our approval to the exclusion of
other products of suitable composition. All chemicals should be used
in accordance with directions on the manufacturer's label. Use
pesticides safely. Read and follow directions on the manufacturer's
label.