Management of Drywood Termites: Past Practices, Present Situation and Future Prospects - Urban Insect Pests: Sustainable Management Strategies - page 133

Economic Importance as Pests strategies, including the ability to fuse and

accept orphans, as well as the size of
resource that can be infested and the ease of
transporting such items, could also explain
failed treatments, especially reports for the
need of re-treatments (Lewis, 2009b; Lewis
and Rust, 2009; Rust and Venturina, 2009;
Lewis et al ., 2009, 2011). Because of the
economic importance of drywood termites
and their potential for invasive spread, the
following sections review efforts to detect
and control these pests.

Designation of pest status, being a human
construct, varies for different species of
drywood termites and depends heavily on
the degree of urbanization. The fi rst review,
based on an assessment of surveys that
examined the global economic importance
of drywood termites, lists nine pest species
(Light, 1934a,d). A half-century later, Su
and Scheffrahn (1990) listed 11 species of
drywood termites of economic importance
in North America and Evans et al. (2013)
catalogued an additional fi ve pest species
that display broad, international distri-
butions. Combining all published reports,
less than 5% of the species contained in the
Kalotermitidae have economic importance.
Of the 28 invasive termite species listed by
Evans et al . (2013), however, eight or 35%
are Kalotermitids. Globally, drywood ter-
mites account for at least 20% of the
estimated US$40 billion spent annually for
termite control (Rust and Su, 2012). Only
species in the family Rhinotermitidae have
a higher potential for movement between
and within urban habitats (Evans et al .,
2013). It is clear from our review of the
literature that any increase in densely
populated urban habitats and global trade
will heighten the economic importance of
drywood termites in the future.
The current distribution of drywood
termites has much to do with an adaptive
biology and cryptic lifestyle that includes a
particular physiology that permits exploit-
ation of cellulose within xeric habitats and
the ability to create viable propagules
because of their reproductive fl exibility
(Evans et al ., 2013). They are remarkable in
their conservation of moisture that features
the production of diagnostic, six-sided
faecal pellets, the result of compacting
faecal material to retain metabolic water
and allowing many species to fl ourish in
dry conditions (Rust et al ., 1979). The
evolutionary costs to survival on water-
depleted wood in dry habitats include small
colony size, averaging from a few hundred
to several thousand individuals (Lenz,
1987; Korb and Lenz, 2004; Lewis et al. ,
2013). Flexibility in colony reproductive

Detection and Inspections

The process of identifying drywood termite
infestations in a building is time consuming
and can be fraught with false negative and
false positive outcomes. The industry stand-
ard for drywood termite detection and
inspection involves a visual search, a
process that may also include the use of a
fl ashlight and metal probe, to pierce
suspected wood for signs of feeding activity
(damage), faecal pellets and live termites
(Scheffrahn et al., 1993). The effectiveness
of visually searching for drywood termites
is highly variable and best when the affected
wood is exposed and easily accessible. It is
important to note that inaccessible areas in
buildings, i.e. crawlspaces, attics and
covered walls, may exceed 45% of the total
area searched during a visual inspection
(Lewis et al ., 1997, 2009, 2011). Visually
locating evidence of termites and damage,
especially for incipient colonies behind
wall coverings or in hard-to-reach locations,
can be challenging and lead to missed
infestations (Scheffrahn et al ., 1993; Lewis
et al ., 1997). Over the past several decades,
additional inspection techniques and
devices have been developed that include:
canine searches (Brooks et al ., 2003),
characterization of faecal pellets (Haverty et
al. , 2005; Grace, 2009; Grace and Yamamoto,
2009), fi bre optic devices (Lewis, 2009a),
acoustic detectors (Fujii et al ., 1990;
Noguchi et al ., 1991; Lewis, 2009a, good
review of past research), infrared cameras
(Lewis, 2009a), microwave motion detectors
(Evans, 2002; Fujii et al ., 2007) and portable