Agriculture Reference
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al
., 2009). Interestingly, the greatest mortal-
ity was observed with termites initially
dyed with Sudan Red 7B. Short-term
feeding on low doses of boron resulted in
delayed avoidance and some termites
recovered, limiting the transfer of boron
through the colony (Gentz and Grace, 2009).
This led the authors to conclude: 'Boron
treatments protect wood from sustained
attack, but are very likely poor candidates
as bait toxicants for subterranean termite
control'.
Alternative building materials such as
wood plastic composites (WPCs) have
become very popular in recent years and are
frequently used in porches, fencing, patios,
and around doors and windows. Three
common forming methods are extrusion
(forcing molten composite through a die),
injection moulding (forcing molten com-
posite through a die) and compression
moulding (pressing molten composite
between old halves) (USDA, 2004). Lopez-
Naranjo
et al.
(2012) showed that when
exposed to accelerated weathering, WPCs
made by the profi le-extruded process fared
poorly compared to WPCs made by
compression moulding.
Nasutitermes nigri-
ceps
were also shown capable of removing
the plastics and consuming the wood in
profi le-extruded composites.
For at least 30 years, pyrethroids have
been applied to wood to protect it from
beetles and termites. Creffi eld
et al.
(2013)
report that
C. acinaciformis
was more
sensitive to woods treated with bifenthrin
and permethrin than was
C. formosanus
.
The retention levels of bifenthrin and
permethrin that prevented feeding are con-
siderably lower than those rates approved
for solid wood in Australia. It was reported
that a low concentration of bifenthrin-
impregnated ether-based polyurethane
elastomer kills termites (Rajendran
et al.,
2010). The repellency and biological activ-
ity are probably a result of the bifenthrin's
slow migration to the surface.
The treatment of wood used for power
poles, railroads sleepers and landscaping
that have continuous contact with soil has
always been a major concern. In New
Zealand, a survey showed 0.88% of power
poles were infested with termites. Soil
applications of chlorpyrifos and fi pronil
were in the highest ranking for both
controlling infestations and preventing re-
infestation (Horwood
et al
., 2010). In
Australia, Bioguard® bandages were used
primarily for the remedial treatment of soft
rot fungi on power poles. The bandage or
sleeve was made of a paper lining and a
polyethylene backing and was treated with
sodium fl uoride and disodium octoborate
tetrahydrate. Bandages treated with
fi pronil were as effective as conventional
soil barriers (67% termite free at 12
months) or internal drenches and
conventional soil barriers (76% termite
free at 12 months). The treatment fared
comparably with other methods currently
used by Australian electricity networks
(Horwood
et al.
, 2012).
Effi cacy of Termite Treatments
Evaluating a fi eld trial or a termite treatment
is one of the most challenging problems
when conducting termite research. For
decades, information about the performance
of soil insecticides was solely based on
small plot studies. With the advent of
termite baits, better analyses were necessary
to demonstrate the ability of baits to reduce
termite populations. Mark-and-recapture
techniques and aggression bioassays were
used to identify colonies, and determine
their foraging range and the effi cacy of baits.
With molecular techniques it is now
possible to identify individual colonies,
determine their fate over time and allow for
better-controlled fi eld studies (Vargo and
Husseneder, 2009).
Parman and Vargo (2010) utilized
molecular markers to monitor imidacloprid
treatments and found that 75% of 12 col-
onies attacking structures disappeared and
were not detected for the remainder of the
study. Approximately 71% of the untreated
colonies were detected again during the
2-year study. Similarly, Vargo and Parman
(2012) reported that none of the 11 colonies
attacking structures was detected 90 days
after being treated with fi pronil. Forty
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