CHAPTER immature individuals(Costa-Leonardo, Arab, & Casarin, 2004) social

CHAPTER 2

INTRODUCTION

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1.1  Introduction

Termites are hemimetabolous insects
with colonies constituted of reproductive and immature individuals(Costa-Leonardo, Arab, & Casarin, 2004) social insects
that belong to the order Isoptera(Debelo & Degaga, 2014). Out of 2500
described species throughout the world, about 300 species of termites are
considered as pests(Akhtar & Rashid, 2001). Termites has
been world-wide pests causing significant losses to annual and perennial crops,
as well as damages to wooden components in buildings especially in the
semi-arid and sub-humid tropics(Guan, Chen, Tang, Yang, & Liu, 2011). It became
serious menaces and most problematic pests threatening agriculture and urban
environment. For example, the costs for control and repair due to Formosan
subterranean termites in New Orleans, have been estimated at 300 million
dollars annually(Verma, Sharma, & Prasad, 2009)

More than 175 species of termites
have been described from Malaysia(Ngeel, 1800) with five
species of termites that are of economic importance which cause damages to
structures and crops which are
Coptotermes gestroi, C. havilandi, C. kalshoveni, C. curvignathus and C.
sepanggiensis(Abdul Hafiz Ab. Majid, Abu Hassan Ahmad, Rashid M Z
A, & Che Salmah Md. Rawi, 2007). However,
termites are an important group of insect pests to Malaysia and neighboring
Southeast Asian countries since they contributed approximately 50% of business
turnover of the pest control industry in Malaysia in 2000(Ngeel, 1800).

In the meantime, chemical,
physical, and biological controls remain the methods extensively used to
prevent termite attack on wooden structures. Chemical pesticide has been a
successful method(Verma et al., 2009) and used mainly
as pesticide to control pest such as synthetic pyrethroids (SPs) which is among
the most commonly used pesticides for controlling agricultural and indoor
pests. Thus, humans exposure to SPs might increase the risk of intoxication in
non-target species, such as birds, humans, fishes, and organisms present in soil
and water(Guan et al., 2011)

Biological methods are one of the
suitable alternatives in controlling pest with without dangerous exposure to
chemical substances. The biological methods include botanicals (essential oil,
seed, bark, leaf, fruit, root, wood, resin), fungal, bacterial, and nematode
approaches. These botanicals or plant-derived compounds contain secondary
metabolites and active component that can be extracted to prepare efficacious
and potent biocidal formulations. It can be used singly or in combination to
repel and kill insects(Verma et al., 2009).

 

CHAPTER 3

LITERATURE REVIEW

1.1      
Subterranean
termite biology

It is an essential biotic organism
to the ecosystem as they helps in organic matter recycling(Debelo & Degaga, 2014), recycling
woody and other plant material(Verma et al., 2009). Their
tunneling efforts help to aerate soil(Verma et al., 2009) which helps to
improve soil fertility besides served as food source to other organism(Debelo & Degaga, 2014). Termites are
an also held an important part of the community of decomposers as they are one
of the most efficient lignocellulose decomposer where they are able to
decompose cellulose, the main component of wood(Debelo & Degaga, 2014; Verma et al., 2009). They can be
found abundant in tropical and subtropical environments, help in breaking down
and recycling one third of the annual production of dead wood. However, they
become economic pests when they start to destroying wood and wooden products of
human homes, building materials, forests, and other commercial products(Verma et al., 2009)

Some of the most economically
important wood feeding termites that can be found in the tropics, sub-tropics
and temperate region are species in genera Coptotermes, Odontotermes and
Macrotermes to name the few(Debelo & Degaga, 2014). They also
gives harmful effect especially to the human such as damaging the crops,
forestry as well as damaging the wood structures and building structure such as
houses, furniture and bridges to name the few. Woods are the most common food
sources for termites to eat in the environment, however, different properties
in wood such as hardness, moisture, temperature, wood decayed by fungus, caste
composition, number of termite species in the area and their density,
allelochemicals in the woods and soldier proportion will affect termites
preferences(Iqbal, Khan, & Saeed, 2015) and attract
different species of termites

 

1.2      
Lower
and higher termite

Lower-termites have the ability to
feed on a nitrogen-poor, wood-based diet with help from unique microbial
consortium living in the guts of lower termites. This symbiotic microbe is
essential for wood-feeding where both host and symbiont cellulolytic enzymes
synergize each other in the termite gut to increase digestive efficiency. The
combination of group living and a microbe-rich habitat makes termites
potentially vulnerable to pathogenic infections. Lower termite biology is
tightly linked to symbiotic associations which resulting physiological
collaborations(Peterson & Scharf, 2016)

Lower termites are distinct from
higher-termites where they form relationships with both eukaryotic and
prokaryotic symbionts within their digestive tracts. Lower termites (families
Mastotermitidae, Kalotermitidae, Termopsidae, Hodotermitidae, Rhinotermitidae,
and Serritermitidae) have symbiotic intestinal protozoa and bacteria while
higher termites (Termitidae) have intestinal bacteria only(Lewis, 2009).

1.3      
Coptotermes gestroi

It is one of the Asian subterranean
termites within termite genera Rhinotermitidae. Coptotermes gestroi is regarded as the most economically important
genus worldwide and destructive species(Yeap, Othman, Lee, & Lee, 2007). Coptotermes gestroi is  primarily found in tropical regions(H.-F. Li, Ye, Su, & Kanzaki, 2009) and endemic to
Southeast Asia but human activity has spread this termite species far beyond
its native range (Scheffrahn & Su, 2008).

Damage resulting from a C. gestroi infestation can become severe
in a relatively short time, especially when it is invaded by a large, mature
colony. C. gestroi cause damage
approximately $400 million per year in southeast Asia and marked as the most
destructive pest termite in the urban areas in Southeast Asia(Yeap et al., 2007). In Malaysia,
Thailand, and Singapore, C. gestroi
contributes 85% of the total termite damage in buildings and structures in the
urban area(Yeap et al., 2007),

Geographic distribution of C. gestroi occurs from Assam through
Burma, Thailand to Malaysia and Indonesian archipelago to many parts of the world,
including the New World tropics (Brazil and Barbados), southern Mexico, the
Southeastern United States, some islands of the West Indies, the Marquesas
Islands, Mauritius and Reunion Islands (Indian Ocean), and more recently
Taiwan. (Yeap et al., 2007)

Soldiers of C. gestroi resemble C.
formosanus where both species have tear drop-shaped heads and large opening
on the forehead called the fontanelle. C.
gestroi soldiers constitute about 10 to 15 % of foraging groups,
aggressively bite when challenged, and release a white mucous-like secretion
from the fontanelle. C. gestroi
dispersal flights or “swarms” occur at dusk or at night in which large numbers
of alates leave the colony. In Florida and the West Indies, C. gestroi flights have been record
between February and April. The C.
gestroi flight season ends about when the C. formosanus flight-season begins(Scheffrahn & Su, 2008).

Level of moisture can affect
foraging behavior of subterranean termites in soil and expected to vary
depending on the moisture preference in a given species. The moisture levels
also can influenced termite feeding behavior. Coptotermes gestroi showed that the termites were active and
tunneled the most when offered more humid conditions(Wong & Lee, 2010).

1.4      
Globitermes sulphureus

Globitermes
sulphureus is a mound-building termite species of the family
Termitidae. It is one of the most important mound-building subterranean termite
species in the Southeast Asia region restricted to the Indo-Malayan region. It
is commonly found in coconut and oil-palm plantations in Malaysia and Java and
a major pest in oil-palm and coconut plantations. However, rapid urbanization
in Malaysia and the neighboring Southeast Asian countries causing many
plantations have been cleared and developed into residential premises and
complexes. This species is now can be found along the perimeters of buildings
and structures in Malaysia(Ngeel, 1800). It is
a very common species in Central and South Vietnam where it is considered as a
major pest since it causes extensive damages to wood structures(Bordereau & al., 1997).

This species builds an epigeous
dome-like nest which may reach one to one and half meters in height. The mound
is made of earth, excremental matter and non-assimilated vegetative material
with a thin bark covering the nest and a wall from dense network of fine and
large galleries to protect the colony. The colonies comprise of ten thousands
of individuals where soldiers represent 5 to 10 % of the active population (Bordereau & al., 1997)

One main characteristic of this
species is the soldiers has bright yellow-colored abdomen that contain the
accumulation of the defensive secretion salivary gland that occupy the thorax
and extends to the end of the abdomen(Bordereau & al., 1997; Ngeel, 1800). They also have
well developed slender and curved mandibles of the slashing-piercing type(Bordereau & al., 1997). The body of
termite workers characterized as marble white, and mites were present on the
body(Ngeel, 1800).  Globitermes
sulphureus soldiers are a well-known for their suicidal behavior where they
liberate a sticky defensive secretion by rupturing their body. The soldier
expels a large amount of yellow liquid which entangles both the termites and
their enemies when attacking. Globitermes
sulphureus soldiers have also known as walking chemical bombs.

1.5      
Termite
control and management

Different control methods been
found to control them and some have been adopted so far and the important ones
are physical, chemical and biological method.

1.     
Physical

Physical barriers
are a very popular method of preventing subterranean termite attack on wooden
structures. There are two types of barriers which is toxic and nontoxic. The
toxic barriers include the use of chemical termiticides in the soil around the
structure such as Chlorfenapyr (BASF-Phantom) barrier treatment. It is very
effective as it is non-repellent and has delayed toxicity. In Australia,
protection of structures from subterranean termites has traditionally relied on
the creation of a zone of poisoned soil under and around the structure to
prevent termites gaining access from the ground In the other hand, the nontoxic
physical barriers are substances such as sand and metal that exclude termites
since they are impenetrable. They act as physical or mechanical barriers in
preventing the penetration and damage of termite to the building.

Freezing treatment
is also one of the physical controls. However, they cannot be used for large
areas, as it can shatter window glass. Tarps will be used for larger areas such
as porches. Liquid nitrogen is pumped into the infested area, chilling the area
until 20 F, thus, it makes the termite freeze. Then, gas is vented off and the
tarps are removed.

Electrical treatment
is the treatment of infested wooden material with electric shock. An
Electro-Gun is placed on one side of the infested timber, and an electrical
shock of low current (w0.5 amp), high voltage (90,000 V), and high frequency
(60,000 cycles) is passed through the wood and termite galleries and ends at
the ground which makes the termites died(Verma et al., 2009).

 

2.     
Chemical

It is the most important and most
widely used to reduce the infestation of termites. Several termiticides
containing active ingredients such as bifenthrin (MakhteshimAgan-Seizure 100
EC), chlorfenapyr (BASF-Phantom), cypermethrin (Effecticide-Spraykill),
fipronil (BASF-Termidor), imidacloprid (Bayer–Gaucho) and permethrin
(BASF-Coopex TC Termiticide) are registered for termite control around the
world under various brand names(Verma et al., 2009).

One of the study have been done
where, the wooden stakes coated with 10% calcium carbonate in gelatin solution,
5% copper sulphate in gelatin solution and 12% calcium carbonate mixed with 10%
zinc oxide insodium silicate solution prevented termite attack in soil up to 2,
4, and 5 years. The control wooden stakes were found to be severely damaged by
termites within 6 months. Stakes coated with Solignum used as a standard wood
preservative for comparison remained free from termite infestation for a period
of 5 years.(Verma et al., 2009)

Subterranean termite controls by baiting
system have been used a lot recently. The principle of termite baiting system
is the active ingredient introduced into a station and termites locate a
station and begin to feed. The active ingredients of chitin will synthesis
inhibitors which cause metabolic disorders molting to the termites where it
cannot form a chitin and died. This effort is one of the best ways to reduce
environmental contamination from pesticide exposure(Kuswanto, Ahmad, & Dungani, 2015).

Chemical treatments can also
include groomable coating and soil termiticide injection to name few. Groomable
coating or trap-treat-release (TTR) is a technique for suppressing or killing
social insect colonies, particularly those of subterranean termites.

The TTR method was developed by Dr.
T. G. Myles at the University of Toronto where in the TTR, the toxicant is applied
termite bodies externally as a groomable coating. Social behavior of termites
will results in the ingestion of the pesticide and will be further distributed
by mutual feeding behaviors. The study shows that, under laboratory conditions,
an extraordinarily high kill ratio of the colony can be achieved where 1
treated termite can kill over 1000 untreated termites confined in a petri
dish.  On the other hand, in field
conditions, around 50–100 termites were estimated to be killed for each termite
treated.(Verma et al., 2009)

 

3.     
Biological

Plant essential oil.
Insecticidal activity of essential oils was evaluated as early as 1972 where
some plant essential oils has been shown not only act as repellent, but also
have contact and fumigant insecticidal actions against specific pests. Various
essential oils have been evaluated against termites. Repellency and toxicity of
essential oils from vetiver grass, cassia leaf, clove bud, cedarwood, Eucalyptus
globules, Eucalyptus citrodera, lemon grass, and geranium against Formosan
subterranean termites was reported(Verma et al., 2009).

Plant extract.
Studies have been done to investigate the ability of three natural products
(neem extract, capsaicin, and gleditschia) to reduce the number of microbes (S. leidyi, H. hartmanni, P. grassii, and
spirochaetes) present in the hindgut of the Formosan subterranean termite.
Neem extract significantly reduced the population of

P.
grassi and spirochaetes
and was found to be most potent at 1 ppm concentration which cause 100% termite
mortality. Anthracenes, anthrones, anthraquinones, and xanthones acts as
deterrents, monoterpenoids, alkaloids, hydrocarbons toxic, plant flavonoids,
antifeedant and related compounds toxic against termites

Resin.
Dipterocarp timbers are well known as being resistant to biological attack from
pests. Shorea robusta has been shown
to be highly resistant to the termites M.
beesoni and H. indicola.
Dipterocarp woods cause mortality to insects that feed on them. In a 3-month
test period, termites feeding on Shorea
species show higher mortality percentage compared to termites feeding on the
nondipterocarp Dyera costulata

 

1.6      
Pandanus amaryllifolius

It is a tropical aromatic plant
commonly known as pandan with common name of Pandan. Its genus is pandanus
under pandanaceae family with screw pine type. The plant propagated through
vegetative parts since it does not produce any fruits and it is sterile. The
leaves can be used in both fresh and dried form but it cannot be consumed. It
is mainly used as flavoring agent in Asia.

The flavor it gives is due to a
compound called as 2-acetyl-1-pyrroline where it is naturally produced in rice
too(Faras, Wadkar, & Ghosh, 2014). The leaves are
said that can be used as cockroach repellent against Blattella germanica. Based on the analysis of the volatile
essential oils, MacLeod and Pieris (1982) found that this Pandanus leaves
species is rich in terpenes and sesquiterpene hydrocarbons (6 – 42%), as well
as the major aroma component – 2-acetyl-1-pyrroline (2AP)(J. Li & Ho, 2003).

Besides, the leaves also have been
reported to contain maltodextrin and total carbohydrate content in the leaves
is reported to be as high as 17%. The leaf extracts have been used many times
spray dried as fortifying agent for carbohydrate supplements besides
controlling certain human diseases such as hair loss, dandruff; neurasthenia,
aneroxia and sore pains to name a few(Faras et al., 2014). The extract of
pandan leaves can significantly reduce postpandrial blood sugar but
antihyperglycemic mechanism of pandan leaves are known only little. Peungvicha
experiments of pandan shows that pandan roots extracts are found to be
effectively reduce blood glucose levels in streptozotocin-diabetic rats besides
it might contain some toxicity since the rat liver enzymes is increased and
caused congestion in the lungs, liver, and kidney(Chiabchalard & Nooron, 2015).

 

1.7      
Citrus hystrix

It is a citrus plant commonly known
as Kaffir Lime or limau purut. Its scientific name is Citrus hystrix from Rutaceae family. Kaffir lime has great
potential in research and commercialization for aromatherapy and spa practices,
solution for insect repellent, making shampoo, antioxidants compound and beauty
product(Kasuan et al., 2013). The zest of
the rind and the juice is usually used in cooking. It is highly notable that
the peel, twig and leaves of the Kaffir lime are used to extract citrus oil
which is used by the food industry. Kaffir lime fruit is about the size of a
western lime with thick rind, knobby and wrinkled structure. The fruit is dark
green and round in shape and as the fruit becomes older, the colour fades to a
lighter, yellowish green. All parts of the plant are strongly aromatic. It is
believed that the peel contains a wholesome amount of pectin since it belongs
to the genus Citrus. However, if the Kaffir lime peels is treated as waste
materials, it may create environmental problems such as water pollution since
the biomaterials presence such as peel oil, pectin, as well as sugar will
stimulate aerobic bacteria to decompose the biodegradable organic matters into
products such as carbon dioxide, nitrates, sulfates and phosphates in water(Shaha, Punichelvana, & Afandi, 2013). Kaffir lime is
a variety of citrus which is native to Indonesia, Malaysia and Thailand.
Previous study showed that the leaf of this plant contains alkaloid, flavonoid,
terpenoid, tannin and saponin compounds. The methanolic extract of leaves of
kaffir lime is known to inhibit the herpes virus and as mosquito repellent(Loh, Awang, Omar, & Rahmani, 2011).

 

1.8      
Azadirachta indica

It is an evergreen tree, cultivated
in the arid regions of Africa, Asian(da Costa, 2010) and Indian
subcontinent with common name, neem or mambu. It is a member of the mahogany
family, Meliaceae. Neem trees are fast growers and it will grow where rainfall
is only 18 inches per year. Besides, it can thrive in areas with extreme heat
up to 120 degrees. Neem tree has a productive life span of 150 – 200 years and
it can be found all over in Malaysia where it exists mainly in Kedah, Penang,
Langkawi and Perlis(Kumar & Navaratnam, 2013). Every part of
the neem tree has been used in traditional folk medicine as a household remedy
in India against various ailments and also as a pesticide(da Costa, 2010). Different
parts of the tree contain several active substances that give unusual
effectiveness on a wide spectrum of pests, including fungi.

Azadirachtin, a
tetranortriterpenoid obtained from neem seeds is used as natural biopesticide
due to its efficacy, biodegradability and minimum side effects(da Costa, 2010). Neem leaves
have been used to study the efficiency of botanical extract on termite Macrotermes spp in the Termitidae family
in order to identify effective botanical and optimum concentration to be used
to the termites in Macrotermes spp.
The total of five plant species have been used ( Azadirachta indica, Jatropha curcas, Maesa lanceolata, Chenopodium
ambrosoids and Vernonia hymenolepis) each at four concentrations ( 10%,
20%, 30%, 35%). A.indica take the
shortest lethal time for 100 % mortality with 35 % concentration(Addisu, Mohamed, & Waktole, 2014).

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