Agriculture Reference
In-Depth Information
3. Determine the likely extent of both the
current damage and the at-risk timbers and
whether structural repairs are required.
4. It may well be that no actions are
warranted or that timber replacement is the
best option.
If the beetles are still active but have no
potential for re-infestation, the choice
becomes between insecticidal application
to prevent the timbers losing their ability to
perform as required or, if the timbers are
unlikely to be structurally compromised,
taking no action other than to monitor
events. Where an insecticidal application is
warranted, the choice of active ingredient
and application method is generally
dependent on the timber factors not the
type of beetle. The following control
methods are widely used.
tunnel so that, while they do move, these
movements are harder to detect than those
of termites. Wood borers feeding on
undecayed timber tear and snap wood
fi bres, which results in acoustic events that
are readily detectable (Schofi eld, 2011;
Creemers, 2013). They may also be detected
with X-ray devices (Krajewski et al ., 2012).
There is also potential for beetle detection
on the basis of their chemical emissions
(Holighaus, 2012; Schott et al ., 2013) but
commercially useful tools to make use of
this are not yet available. Tools and
approaches initially developed for detecting
termites such as the Termatrac microwave
radar unit (Peters and Creffi eld, 2002),
sniffer dogs and thermal imaging cameras
are less effective at detecting beetle larvae
(Zahid et al ., 2012) because the beetles'
limited movements and dispersal through
the timbers provides weaker signals.
Brozovsky et al . (2008) and Reinprecht and
Pánek (2013) demonstrated that the decay
of ultrasonic pulses could be used to assess
individual timber elements. Beyond these
tools, specialist inspection relies on
invasive techniques such as probing and the
drilling of cores.
Fumigation
Fumigation using penetrating gas is a
preferred method for high-value items such
as furniture. The treatment method is fast,
penetrates fully and kills all life stages.
Methyl bromide and sulfuryl fl uoride have
had broad use but face restriction owing to
adverse environmental effects. Another
alternative is the Commonwealth Scientifi c
and Industrial Research Organisation
(CSIRO)-developed ethane dinitrile (Water-
ford et al. , 2004), which is in use in the
Australian and Malaysian markets (APVMA,
2013). All fumigants are potentially danger-
ous chemicals that require specialist train-
ing and usually applicator licensing.
Modifi ed atmospheres with elevated
concentrations of carbon dioxide (CO 2 ) or
nitrogen (N 2 ) or vacuum treatment (reduced
O 2 ) may also be effective (Emecki, 2010).
Timber is not uniformly gas permeable (Ren
et al ., 2011). As with moisture, transfer of
gases across the grain is much less than
along the grain. The observed transfer/
sorption of fumigants also differs between
hardwoods and softwoods (Ren et al ., 1997).
The full range of fumigants has not been
tested on timber pests, meaning that some
existing chemistries may fi nd future use
(Emecki, 2010). One reason for the paucity
Management of infestations
Selection of appropriate management
methods is heavily dependent on a range of
factors such as access, timber value, budget
and whether surface damage is tolerable. In
sub-fl oor hardwood timbers with little sap-
wood and no visual amenity, attacks by
Lyctus are typically ignored because struc-
tural amenity will remain (Creffi eld, 1996).
By contrast, any beetle attack on museum
specimens is a defi nite cause for concern
(Querner et al ., 2013). When assessing
which control measures to implement, it is
important to consider evidence gathered
and the range of possible actions. For
structures, the decision-making steps are:
1. Identify the beetles and the timbers
under attack.
2. Determine whether the infestation is
still active and if there is a potential for re-
infestation.
 
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