364 A. D. N. T. Kumara et al.
the damage efficiently and is able to detect 97 %
of affected palms. Recently, the image-processing
method was developed by Al-Saqer and Hassan
( 2011 ).
Management
Because it is difficult to detect the damage by the
RPW during the early stages of infestation, em-
phasis is generally focused on preventive mea-
sures relying on chemical applications. Control
methods against RPW range from dusting of the
leaf axils with insecticides after pruning, or spray-
ing of the palm trunk, to localized direct injec-
tions of chemicals into the trunk (Faleiro 2006 ).
All these treatments are often complemented
with cultural and sanitary methods that include
early destruction of the infested palm (Kurian
and Mathen 1971) and prophylactic treatment
of cut wounds (Pillai 1987). In newly spreading
areas, preventive measures should be important
including plant quarantine and plant certification,
mass trapping using ferrugineol-based food-bait-
ed traps (Hallett et al. 1993 ), crop and field sani-
tation, preventive chemical treatments of gases,
filling frond axils of young palms with a mixture
of insecticides and curative treatments of infested
palms in the early stages of attack, eradicating
severely infested palms. These palms should be
removed and destroyed by shredding (Dembilio
and Jacas 2012). For avoiding infection, differ-
ent precautionary measures have been consid-
ered, including avoiding mechanical damage or
wounding the palm, application of repellents for
the wound of palm trunks, containment/destruc-
tion of infested plants, field sanitation methods.
Insecticides
The most common and practical measure in
chemical control is mainly based on the repeat-
ed applications of large quantities of synthetic
insecticides employed in a range of preventive
and curative procedures designed to contain the
infestation. These procedures have been devel-
oped and refined since the 1970s in India, when
work on application of organophosphates and
carbamates ensured these chemicals to become
the mainstay of the chemical approach to control
RPW (Murphy and Briscoe 1999 ). In Sri Lanka,
20 to 30 ml of monocrotophos trunk injection to
the affected palm at 2-monthly intervals twice
has been recommended. (Fernando 2005 ). In
Spain, a minimum of 8 preventive treatments
with chlorpyrifos, imidacloprid, phosmetand,
thiamethoxam per season (from March to No-
vember) are recommended to be applied as
spray on the stipe, injected into the trunk, or as
a drench, (Dembilio and Jacas 2012). Radiant
(spinosad), Pyriproxyfen (IGRs) and Neemazal
(plant extracts) were evaluated in laboratory
against the RPW, and acute toxicity was record-
ed by high percents after treatment by Radiant
followed by Pyriproxyfen while Neemazal did
not exhibit acute toxicity. All tested insecticides
exhibited lethal effect in the treated larvae and
in the resulted pupae and adults from the treat-
ment. Radiant was consistently the most toxic
insecticide to the RPW based on LC50 record-
ed for general mortality (Hamadah and Tanani
2013 ).
The formulation, Imidacloprid SL, was suc-
cessfully tested by Kaakeh ( 2005 ), in laboratory
and semi-field assays against R. ferrugineus. Fur-
thermore, high efficacy insecticides and botani-
cal pesticides, biological control methods like
entomopathogenic nematode, fungus and sterile
insect techniques can be used as a package for
preventive control of RPW. However, the sys-
temic insecticide application through root feed-
ing and stem injection are the only methods suc-
cessfully reduced the RPW population in affected
areas in initial stage of the infection (Prabhu et al.
2009 ; Khalifa et al. 2004; Abbas 2010 ). Efforts
to develop biological management of RPW are in
early stages (Abdullah 2009 ). Preliminary field
trials suggest that an entomopathogenic fungus,
Beauveria bassiana, partially controls RPW
(Dembilio et al. 2010a). Combination trials of
imidacloprid and entomopathogenic nematode
Steinernema carpocapsae Weiser and the use of
entomopathogenic nematode were initiated in
countries like India and Saudi Arabia (Dembilio
et al. 2010b).