Agriculture Reference
In-Depth Information
candidate as a wood preservative (Rodrigues
et al ., 2011). Vapours from 29 natural prod-
ucts and their derivatives including citro-
nellal, geraniol, d-limonene and l-linalool
were tested against C. formosanus (Raina et
al. , 2012). Only tetrahydrocarvone provided
98.6% kill of workers in 7 days. Some
compounds derived from a natural-product-
based chromene amide isolated from the
shrub of Texas torchwood, Amyris texana ,
exhibited dose-dependent toxicity against
C. formosanus workers, producing 90-
100% mortality of C. formosanus in 4 days
(Meepagala et al ., 2011). Naphthalene, once
widely used to protect fabrics from beetles
and moths, and some similar derivatives
were tested against C. formosanus (Ibrahim
et al ., 2010). Both 1- and 2-methoxy-
naphthalene and 1'- and 2'-acetonaphthone
were more repellent and toxic than
naphthalene. Because of their volatility, the
use of 1- and 2-methoxynaphthalene may be
useful in situations where fumes are not an
issue. In addition two constituents, -elemol
and -terpineol, of the essential oil extracted
from the evergreen tree Cryptomeria
japonica were found to be toxic to C.
formosanus workers (Cheng et al. , 2012).
Native lumbers known for deterring
termite feeding are often the subject of
chemical studies. Scopoletin was isolated
and identifi ed from an Indonesian plant
Protium javanicum and along with
7-alkoxycoumarins and related analogues
was reported to be toxic and deterred
feeding of C. formosanus (Adfa et al ., 2010,
2012). Ethyl acetate extracts of the
heartwood from Hymenaea stigonocarpa
was more active against termites than the
individual fl avonoids, namely hultenin,
taxifolin, quercetin and 7-methoxycatechin,
isolated from the extract. The antioxidant
and antitermitic activity from analysed
samples decreased in the following order:
EtOAc crude extract > quercetin > 7-metoxi-
catequin > taxifolin > hultenin, which
suggests that extracts' combined toxicity
and antioxidant properties to give the
H. stigonocarpa heartwood natural resist-
ance (Maranhão et al. , 2013).
In Indonesia, a traditional method of
protecting wood against biological deterior-
ation is to smoke it (Hadi et al. , 2010). The
smoke is generated during a heat process to
make charcoal (Hadi et al. , 2012). During
the process large numbers of polycyclic
aromatic hydrocarbons are released and
captured by the target wood. Woods
susceptible to attack from Coptotermes
curvignathus are converted to highly resist-
ant woods after being exposed to smoke
from burning mangium wood ( Acacia
mangium ).
Wood Treatment
Wood building materials have been treated
with various chemicals for centuries to
prevent fungus and arthropod attack.
Environmental and human health concerns
have been raised concerning many of these
compounds and, in recent years, there has
been a transition away from chromated
copper arsenate (CCA) treated wood to
arsenic-free wood (Vlosky et al ., 2009b).
With the restricted uses of CCA-treated
wood in residential settings in the USA,
environmentally acceptable alternatives
such as copper azole (CA) and alkaline
copper quaternary (ACQ) are now widely
used worldwide (Tascioglu and Tsunoda,
2012); however, it was reported that ACQ
and CA did not fully protect lumber and
that remedial treatment of cut-ends at
building sites may be necessary to further
protect the wood. Quaternary ammonia
compounds (didecyl dimethyl ammonium
chloride [DDAC] and didecyl dimethyl
ammonium tetrafl uoroborate [DBF]) provide
protection from C. formosanus feeding to
both solid woods and plywood (Terzi et al .,
2012b). The quaternary ammonia com-
pounds are possible wood-treating altern-
atives because of their low mammalian
toxicity and effi cacy against bacteria and
fungi. Wood treated with quat-silicone
micro-emulsion and amino-silicone macro-
emulsion resisted feeding damage by
Coptotermes acinaciformis and Mastotermes
darwiniensis (Ghosh et al. , 2012).
Workers of C. formosanus fed on wood
treated with borates were reported to trans-
fer boron to unexposed nest mates (Gentz et
 
Search WWH ::




Custom Search