By
Arman AVAND-FAGHIH
armanfaghih@yahoo.fr
Introduction
(history,
geographical distribution and economical importance)
The damage of red palm
weevil (RPW), Rhynchophorus ferrugineus (Olivier), has been reported for
the first time in 1990 on traditional date palm groves in Saravan region (Sistan
& Balouchestan province, Iran). This insect pest has been probably introduced to
Iran by illegal importation of infested date palm offshoots from Pakistan where
it is considered as an endemic pest. RPW has been considered as the most
destructive and the most important pest of date palm menacing the production of
date in Iran known as the first producer in the world with 32 millions of palms
on 154,000 ha and 707,000 tons of yield per year. In infested area, 0.7% of date
palms are infested by the pest every year (about 7,000 infested palms during 7
years) which is an important economic damage. Five-to 20-years old date palms
are more infested than other palms and the Mazafati variety is more preferred by
pest than other varieties in Iranian infested area. A large-scale program has
been implemented very soon after the first report to prevent the spreading of
the pest in the country, to control its damage in the infested area and to
search for new control methods.
The
infested area by RPW in Iran (Saravan region, Sistan & Baloutchestan
province)
Red palm weevil, an internal quarantined pest
in Iran
Internal quarantine
regulations have been executed by interdiction of all date palm organs (except
fruits) exportation from infested area. For this purpose, several quarantine
stations have been installed on all exit roads. The infested area in Iran is
limited to Saravan region at Pakistan borderline until now.
Integrated Pest Management (IPM) strategy for
the Control of RPW in Iran
The conventional control of
pest by chemical insecticides was abandoned very soon because of its harmful
effect on environment. All date palms of infested area has been checked
continuously by technicians to identify the infested date palms by described
symptoms as oozing a viscous and stink brown liquid from the stem, the feeding
sound of larva in stem, the water-stressed aspect of palms and white-dried young
leaves of palm and especially of stem-shoots. The infested palms have been
successfully treated chemically by aluminium phosphide (Phostoxin) after
removing the stem-shoots and dried petioles. Phostoxin tablets are placed in the
entrance of larval galleries and the stem is tightly covered by a plastic sheet
to prevent the escape of gas. The plastic sheet is carried off after 2 or 5 days
in hot or cold seasons respectively. The continuous execution of this method for
5 years decreased the number of infested palms from more than 1000 at the
beginning years to about 300 in 1994. But the subsequent introduction of pest to
new villages and in one hand the increase of infested area and on the other hand
the limited number of skilful technicians have reduced the efficiency of this
approach. The most important disadvantage of this method is that it is not
possible to identify the infested palms in early stage and before a high
damage. So the preventive methods have been developed in parallel with chemical
curative approach in the frame of IPM to avoid new infestations. As the adults
are attracted by the odours emitted by wounds, it has been recommended to
prevent the pruning of leaves and stem-shoots during the hot seasons (pruning
can be carried out between mid December and mid February when the adults do not
fly), to control the damage of other stem pests as Oryctes elegans Prell,
Pseudophilus testaceus Gah., and rats that provide penetration and egg
laying sites for RPW. Except wounds, the connection between the stipe and
stem-shoot is another suitable site for egg laying and penetration of adults.
Thus the elimination of stem-shoots is recommended during the cold season. It
has been suggested also to treat all wounds by a gypsy paste especially during
hot seasons. The date palm stem traps had been used at the first years after RPW
introduction but they became the rearing sites of pest because of the
difficulties for their management.
The aggregation
pheromone-baited traps as an important component of IPM
The identification of
male-produced aggregation pheromone of RPW has opened a new horizon for IPM of
this insect. The pheromone-baited traps have been optimised for trapping of RPW
in Iranian situations. The plastic bucket traps (24 l) with 8 openings (5
´
8 cm) on the lids have been used as traps. The ferrugineol dispensers with a 5
mg/d release rate are as effective as ones with 55 mg/d. A piece of date palm
offshoot (about 1 kg) in a punctured plastic bag is used as the synergist in
traps. The pheromone dispenser and plant bait are suspended in trap below the
lid by metal wires. An aqueous solution of a detergent (2%) is used as the
retention system of captured insects and for providing enough humidity in trap
to prolong the efficiency of plant bait. The traps are placed at ground level
and attached to date palm stems. The plant baits are renewed every 14 days. The
traps catch significantly more females than males, which is an interesting
advantage for developing the mass-trapping method. A low trap density and
precisely taking into account of the palm susceptibility has been recommended
for mass trapping method in Iranian traditional date palm groves. A lower
density of traps (0.5 trap/ha) shall be installed in more susceptible date palm
grows with young palms and sensitive variety.
Obstacles and perspectives
The strong heterogeneity of
traditional date palm groves of infested area (different densities of palms of
diverse varieties and ages) and the abandoned gardens are the most important
obstacles for developing an IPM strategy.
A research program is under way
under the supervision of Unité de Phytopharmacie et Médiateurs Chimiques (INRA,
Centre de Versailles, France) to identify the plant synergists of RPW
aggregation pheromone to facilitate the agronomic application of
pheromone-baited traps for mass trapping of RPW.
Partners of RPW project in Iran (alphabetic
order)
-
Plant Pests
& Diseases Research Institute (research projects)
-
Plant
Protection Organisation (financing for quarantine and control methods)
-
Sistan &
Balouchestan Agriculture Organisation (management and realisation of quarantine
and control methods)
References
AVAND-FAGHIH A., GHARIB A.R., 1995.
Study of biology and control of red palm weevil (Rhynchophorus ferrugineus
Oliv.) in Saravan, Proceedings of the 12th Iranian Plant
Protection Congress (Karadj, Iran).
AVAND-FAGHIH A., 1996. The biology
of red palm weevil, Rhynchophorus ferrugineus Oliv. In Saravan region (Sistan
& Balouchestan province, Iran), Applied Entomology and Phytopathology, Vol.63,
1&2, Feb. 1996, 61-89.
AVAND-FAGHIH A., 1997. Research on
the control of red palm weevil, Rhynchophorus ferrugineus (Oliv.), (Col.:
Curculionidae) by synthetic attractants in Sistan & Balouchestan province
(Iran). A thesis submitted in partial fulfilment for the degree of M.Sc. in
Agricultural Entomology, University of Tehran, College of Agriculture,
Department of Plant Protection.
F.A.O.,
1995. Report of the expert consultation on date palm pest problems and their
control in the Near East. 22-26 April 1995, Al-Ain, United Arab Emirates, 58 pp.
FARAZMAND H., RASSOULIAN GH.R.,
BAYAT-ASSADI H., 2000. Comparative notes on larval growth and development of red
palm weevil, Rhynchophorus ferrugineus Oliv. (Col.: Curculionidae), on
date palm varieties in Saravan region. Journal of Entomological Society of
Iran, Vol.19, No.1&2, 1-14.
FARAZMAND H., RASSOULIAN GH.R.,
TALEBI-JAHROMI KH., 2001. Host preference of red palm weevil, Rhynchophorus
ferrugineus Oliv., on date palm important varieties of Balouchistan, Iran in
field condition. Iranian Journal of Agricultural Sciences, Vol.32, No.1,
121-129.
FARAZMAND H., 2002. Investigation
on the reasons of food preference of red palm weevil, Rhynchophorus
ferrugineus Oliv. Journal of Applied Entomology & Phytopathology, Vol. 70,
No. 1, (In press).
ROCHAT D., AVAND-FAGHIH A.,
MALOSSE C., EBRAHIMI A., 1998. Extraction, identification and application of
the aggregation pheromone of the red palm weevil, Rhynchophorus ferrugineus
Oliv. (Col.: Curculionidae) in Saravan region, Proceedings of the 13th
Iranian Plant Protection Congress (Karadj, Iran).
ROCHAT D., AVAND-FAGHIH A., 2000.
In: KLEEBERG H., ZEBITZ C.P.W., Practice oriented results on use and production
of neem-ingredients and pheromones, 219-224, Trifolio-M GmbH, Sonnenstr. 22,
D-35633 Lahnau.
ROCHAT D., AVAND-FAGHIH A.,
FARAZMAND H., MOHAMMADPOUR K., 2001. Effect of red palm weevil mass trapping
with synthetic pheromone in traditional Iranian date palm groves, Second
Asia-Pacific Conference on Chemical Ecology, August 7-11 2001 (Penang, Malaysia)
50-51.
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RPW World Report
