Status and Management of Three Major Insect Pests of Coconut in the Tropics and Subtropics 363
for 25–105 days, and it becomes a pupa in a co-
coon made up of chewed-up tissues of the plant.
The developmental state of the pupa usually takes
11–45 days (Abraham et al. 1998 ; Faleiro 2006 ).
The adult RPW emerges out, or mostly the RPWs
complete several generations inside the infested
palm. Therefore, the RPW infestation is detected
at such a late stage that it is not possible to save
the infested palm. The RPW stays in the infested
plant till it is hollow from inside and dead. After
the death of the infested palm, the RPW moves to
the neighboring palms. The rate of multiplication
of the RPW is high as the female lays eggs con-
tinuously throughout the year (Fig. 2 ).
Management
Detection
The most critical factor in the management of the
RPW is the detection of the damage at an early
stage before severe damage to the internal tis-
sues of the palm. The female weevil lays eggs on
wounded tissues of the palm and the grub bores
and begins its life in the palm, and normally
never comes outside. Therefore, neither the grub
nor the damage caused by it can be readily seen.
Sometimes, a few small holes occur in the crown
or on the soft stem. In many cases, the drying
up of the young heart leaves or splitting of the
petioles near the area of attack can be observed.
But most often the attack by the weevil is no-
ticed only when palms have been fatally infested
and are beyond recovery (Menon and Pandalai
1960 ). The damage caused by the pest is severe,
and once the weevil gets access to the palm, the
final death of the palm is more or less certain.
The first indication is the presence of holes on
the stem with chewed fibrous material, some-
times protruding out (Child 1974 ). The RPW is
a concealed tissue borer and all of its life stages
are found inside the palm. Damage symptoms are
indicated by the presence of tunnels in the trunk,
oozing of thick yellow to brown fluid from the
palm, the appearance of chewed-up plant tissue
in and around an opening in the trunk, the pres-
ence of a fermented odor from the trunk, or top-
pling of the crown (Kaaheh et al. 2001 ).
Several detection methods are employed
to detect the infected palms for treatment. The
field staff surveys susceptible fields and regu-
larly checks the symptoms of the infested palms.
When the larvae are present in the palm, they
produce sounds, due to chewing of palm tissue,
crawling, emission, and quick oscillation (Pinhas
et al. 2008 ).The sound generated by the chewing
grub can be detected by endoscope or by placing
the ear on stem (Hamad and Faith 2004 ). In the
Middle East region, the infested palms produce a
typical fermented odor, detected by sniffer dogs
(Nakash et al. 2000 ). However, this may be pos-
sible if a considerable number of larvae are pres-
ent, and at this stage the palm may be moderately
to extensively damaged. Hence, the detection of
infestations at an early stage is important to save
the palms. Utilization of sound methodology to
detect RPW-infested date palms has been attempt-
ed (Soroker et al. 2004 ), and an electronic device
to detect infested coconut palms, although with
less reliability and efficiency, has been developed
in Sri Lanka (Fernando pers. comm.). Currently,
digital signal-processing techniques are also used
to identify the RPW in the palms (Al-Manie and
Alkanhal 2005 ). Pinhas et al. ( 2008 ) developed a
prototype that detected larvae of the RPW in off-
shoots of palms, which could be used in inspec-
tion of horticultural and ornamental palms traded
between countries. However, this device is not
portable. Siriwardana et al. ( 2010 ) developed and
evaluated the portable RPW acoustic detector,
which can be used for detecting the early stage ofFig. 2 Lifecycle of the RPW (Source: Prabahu and Patel
2009 )