EUROPEAN AND MEDITERRANEAN PLANT PROTECTION ORGANIZATION
10-15862
PPM, point 7.1
Draft Data Sheet – Extensive version
Diocalandra frumenti
IDENTITY
Name: Diocalandra frumenti (Fabricius, 1801) Syst. Elenth. 2:438
Synonyms: Calandra frumenti (Fabricius, 1801)
Sitophilus frumenti (Fabricius) Schoenherr, 1838:982
Diocalandra frumenti (Fabricius) Faust, 1894:354
Calandra bifasciata Boisduval, 1835: 445
Calandra montrouzieri Chevrolat, 1882: CXXVIII
Sitophilus subfasciatus Boheman, 1838: 971
Sitophilus stigmaticollis Gyllenhal, 1838: 972
Diocalandra frumenti var. stigmaticollis (Gyllenhal) Kolbe, 1910: 46
Sitophilus subsignatus Gyllenhal,1838: 973
Sphenophorus cruciger Motschulsky, 1858:69
Calandra punctigera Pascoe, 1885: 305
Callandra sechellarum Kolbe,1910:46
Taxonomic position: Insecta: Coleoptera: Curculionidae: Rhynchophoridae: Diocalandrini
Notes on taxonomy and nomenclature: The above taxonomic determination and the
following notes follow a general scheme of classification used by E. C. Zimmerman in his 8
volume series of Australian weevils. Zimmerman (1993) raised the Rhyncophoridae to Family
status within the super family Cuculionoidea and proposed a new tribe, the Diocalandrini to
include the genus Diocalandra with Arecaceae as hosts but excludes the seed feeding genus
Sitophilus. Diocalandra are small, slender weevils but the loss of sternite 9 in male specimens
separates them from Sitophilus that they closely resemble. Morimoto (1978) has recognized
and produced a key to 9 species of Diocalandra.
D. frumenti was originally described by Fabricius in 1801 as Calandra frumenti but since the
adults vary greatly in size, colour and maculation (Zimmerman, 1993), the species has been
redescribed many times (see above synonomy). Zimmerman (1993) indicated that this species
closely resembles D. taitense (Guèrin-Mèneville) from the central and eastern Pacific islands
with which it is often confused and he produced a key to separate the two species.
Common names: Palm weevil borer (English), four spotted coconut weevil (English), lesser
coconut weevil (English), small weevil (Taiwan).
Bayer computer code: DIOCFR
Phytosanitary categorization :
HOSTS
D. frumenti has been collected from at least 17 genera of Arecaceae, with most of these being
economically important palm species cultivated for food, oil, housing or landscape plants.
Major hosts include coconut (Cocos nucifera) and landscape palms such as Phoenix
canariensis and its hybrids (Kahlshoven, 1981, Salomone Suárez et.al., 2000b).
Minor hosts include date palm (Phoenix dactylifera), oil palm (Elaeis guineensis), attap (Nypa
fruticans) and a large number of other landscape palm species. The literature records include
Archontophoenix alexandrea, Bismarkia sp., Caryota sp., Chrysalidocarpus lutescens, Dypsis
lutescens, Dypsis lucubensis, Howea belmoreana, Mascarena verchaffeltii, Metroxylon sagu,
Phoenix loureirii, Phoenix roebelenii, Ptychosperma macarthurii, Ravenea rivularis,
Roystonea regia, Sabal palmeto, Washingtonia spp. and Wodyetia bifurcata (AVA, 2006;
Lepesme, 1947; NGIA, 1998; Salomone & Caballero Ruano, 2008).
It is possible that the species has only recently adapted to the ornamental species in the genus
Phoenix.
Howard et. al. (2001) who cited Lever (1979) as a reference, indicated that species in the
Areca and Borassus genera in addition to Sorghum were also attacked by this weevil.
Although D. frumenti has been raised under artificial conditions on sugar cane, the EPPO
Expert Working Group for the Pest Risk Analysis of Diocalandra frumenti concluded that the
pest is attracted to decaying tissues, but did not consider Poaceae as hosts, as there is only this
record.
GEOGRAPHICAL DISTRIBUTION
“CABI map 249” provides a distributional map of Diocalandra frumenti.
EPPO region: Spain (Canary Islands)
Africa: Madagascar, Mauritius, Seychelles, Somalia, Tanzania (including Zanzibar).
Asia: Bangladesh, India, Indonesia, Japan, Malaysia, Myanmar, Philippines, Singapore, Sri
Lanka, Taiwan, Thailand.
Oceania: Australia (Northern Territory, Queensland, Western Australia), Guam, Palau, Papua
New Guinea, Samoa, Solomon Islands.
South America: Ecuador.
Note: In Spain, the species was found in 1998 in the south of Gran Canaria, Canary Islands
(González Núñez et al., 2002). In Japan, the species was discovered in 1977 on Okinawa,
Ryukyu archipelago from palm trees introduced from Taiwan (Morimoto, 1985).
BIOLOGY
The life cycle was outlined by Hill (1983) to take 10-12 weeks, and included 4-9 days as eggs,
a larval development of 8-10 weeks and a 9-10 day pupation period (in the wild). More
recently, Liao & Chen (1997) reported a similar life cycle duration with individual stages for
egg, larvae and pupae as 6-10; 35-40; and 10-16 days respectively. They indicated that adults
survived 15-22 days. The life stage durations are similar to these found by González Núñez et
al. (2002) in laboratory trials (25 ±1°C, 70%±10 HR) using sugar cane as a food source.
Adult D. frumenti weevils are attracted to sap exuding from wounded palm tissue (Kalshoven,
1981) or from flower bases (Lepesme, 1947) and lay eggs in various sites: inflorescences, the
bases of petioles or peduncles, or in cracks near adventitious roots at the base of the stem.
In Taiwan, female D. frumenti drill holes with their mouthparts to lay eggs near the surface of
an unopened leaf sheath on the palm Mascarena verchaffeltii (Liao & Chen, 1997), whereas
González Núñez et al. (2002) reported that in experiments with sugarcane as the food source,
D. frumenti laid eggs 1.0-2.5 mm deep, and that no sign of oviposition could be seen from the
exterior of the cane.
The average fecundity was 0.13 egg per female per day during experiments on sugarcane
(González Núñez et al. 2002). They considered this low fecundity to be balanced by the high
longevity of the adults, although Liao & Chen (1997) reported that the adults survived only
15-20 days.
The larvae can bore galleries in any part of the palm: roots, petioles, inflorescences, fronds,
leaf sheaths, fruits and to all heights of the trunk (González Núñez et al., 2002; Hill, 1983).
They develop entirely within the palm tree. Gummy exudates are usually seen near the gallery
entrance. Pupation takes place within the larval gallery but no cocoon is formed. González
Núñez et al. (2002) found that on sugar cane, the pupation chamber is formed near the
epidermis of the cane used as food, a circular hole of 1.5 mm of diameter being formed for
exit of the pest. This hole is filled with debris, and the thin epidermis of the cane remains as a
protection. Similarly, Liao & Chen (1997) indicated that the larvae move toward the edge of
the leaf sheath to pupate. The adults remove the debris with their mouthparts to emerge.
Liao & Chen (1997) indicated that 10 or more larvae could develop in each leaf sheath and
Salomone Suárez et al. (2000b) estimated that hundreds of individuals could be found in a
single palm tree.
Picture: Eduardo Franquiz Alemán (2008) Galleries of D. frumenti in sugar cane. used as a food source.
Attack of Phoenix canariensis by D. frumenti
Picture by Francesco Salomone (2008)
DETECTION AND IDENTIFICATION
Symptoms
Feeding damage by weevil larvae may cause premature yellowing and collapse of palm
fronds, beginning with the exterior fronds and moving to the interior ones (Salomone Suárez
et al., 2000b). Infestation is recognised by the emergence holes of 1 to 2 mm diameter in
sound tissues of new and old fronds and in the leaf bases (NGIA, 1998; Salomone Suárez et
al., 2000b). Attack is usually to old, weakened or injured parts of palms, especially to the
edges of older fronds or wound sites (Zimmerman, 1993). Gummy exudates at the opening of
galleries can be observed (Salomone Suárez et al., 2000b). In Australia, the stubs of fronds cut
from the palm or broken by winds are frequently the areas initially attacked. The larvae bore
distally from the petiole (NGIA, 1998; Howard et al., 2001).
Another symptom may involve the premature shedding of fruits (NGIA, 1998). Vanderplank
(1953) claimed that damage by D. frumenti larvae could cause gumosis and immature nutfall
on coconut palms. However, it is possible that the weevils are attracted to the gelatinous
exudates caused by wounding (Kalshoven, 1981) or damage by other insect species, such as
Tirathaba (Lepidoptera: Pyralidae) (Lepesme, 1947) and are not the primary cause of the
gumosis.
Damage can occur on roots, fronds and fruit stalks (Howard et al., 2001). Death of mature
Phoenix canariensis has been reported from Australia (NGIA, 1998) and this weevil is
associated with palm deaths in Gran Canaria (Salomone & Ruano, 2008).
Morphology
The eggs are white, slightly elongate and about 0.9 mm long by 0.3 mm wide (Liao & Chen,
1997). Larvae are white, slightly curved and about 7 mm long when fully grown (9 larvae
were measured by Stuart Smith, Biosecurity and Product Integrity Division, Department of
Primary Industry, Fisheries and Mines, Northern territory, Australia). The dark brown
mandibles are visible and they are slightly plumper at the distal end. Pupae are also white, and
about 6-7 mm long.
Adults are small (6-8 mm long), shiny to dull dark-brown to black weevils with four large
reddish to brownish-yellow spots on the elytra. Sexual dimorphism is evident with females
being considerably larger and by the shape of the posterior apex, and the length and thickness
of the rostrum: the male rostrum being shorter, thicker, and more curved (Hill, 1983).
Fronds of Phoenix canariensis attacked by D. frumenti
Picture: Servicio de Sanidad Vegetal, Gobierno de Canarias (2008)
Galleries of D. frumenti in fronds of Phoenix canariensis
Picture: Servicio de Sanidad Vegetal, Gobierno de Canarias (2008)
Trunck of Phoenix canariensis attacked by D. frumenti
Picture: Servicio de Sanidad Vegetal, Gobierno de Canarias (2008)
Galleries of D. frumenti
Picture by Francesco Salomone (2008)
Detection and inspection methods
Infestation by D. frumenti can be recognised by the emergence holes on new and old fronds
and leaf bases and should be the normal method of inspection (NGIA, 1998). Any palm with
symptoms of premature yellowing of the fronds, particularly if the yellowing sequence is from
the outside to the inside of the crown, or the collapse of palm fronds should be inspected for
the presence of emergence holes and adult beetles or larvae associated with these galleries.
Nevertheless, the species is cryptic and is therefore difficult to detect.
MEANS OF MOVEMENT AND DISPERSAL
Spread: No data is available on natural spread, but adults can move over at least small
distances and this could occur in a nursery situation. Sale or exchange of infested palms can
ensure spread of the pest over long distances.
Pathway: Palms for planting from countries where D. frumenti occurs.
Palm trees are grown around the Mediterranean for fruit production (Phoenix dactylifera) or
ornamental purposes (Phoenix canariensis and many other species).
PEST SIGNIFICANCE
The precise status of this weevil as a pest is open to dispute; some entomologists believe that
the damage is primary and results in appreciable crop losses, but other maintain that this
damage is purely secondary (Hill, 1983). It is considered that the species is associated with
palm deaths in both Australia and the Canary islands (NGIA, 1998; Salomone & Ruano,
2008).
Economic impact
Feeding damage by larvae may cause premature yellowing and collapse of palm fronds in the
crowns (NGIA, 1998; Salomone & Ruano, 2008). Damage can occur on roots, fronds and fruit
stalks which will reduce the vigour of the plant.
The activity of D. frumenti allows the entry of the saprophitic micro-organisms. Gliocladium
vermoeseni, Thielaviopsis paradoxa, Fusarium spp., Aspergillum spp., Cladosporium spp.
and Pennicillium spp. were detected in tissue samples of palms damaged by D. frumenti in the
Canary Islands (Salomone & Caballera Ruano, 2008).
Hill (1983) listed D. frumenti as a major pest of coconut (Cocos nucifera) and oil palm (Elaeis
guineensis). The larvae of D. frumenti may cause gumosis and nutfall of immature coconuts.
D. frumenti has also been found attacking Phoenix dactylifera and its hydrids, though impacts
on this crop are not detailed (Salomone Suárez et al., 2000b). Hill (1983) considered D.
frumenti to be a minor pest of date palm.
D. frumenti has the potential to damage a wide range of landscape palms (see above) and is
known to have caused the death of mature ornamental palms of Phoenix canariensis in
Queensland (Australia) (Giblin-Davis, 2001) and has been associated with palm deaths in
Gran Canaria. Phoenix canariensis is by law the Canary Island vegetal symbol (Ley 7/1991 de
Símbolos de la Naturaleza para las Islas Canarias) and is represented by over 5,000.000
natural palms in La Gomera (one of the smallest island of the archipelago), and by 55.000
palms in Gran Canaria where it is found in natural ecosystems (Salomone & Caballera Ruano,
2008).
In Taiwan, Liao & Chen (1997) reported attacks of D. frumenti on Mascarena verchaffeltii,
Roystonea regia with a damage comprised between 5 and 20%, while the damage on Phoenix
loureiri was estimated lower than 5%.
In Australia, damage by this pest is usually very minor, although where it is associated with
another weevil pest, the sugarcane weevil borer Rhabdoscelus obscurus, the combined attack
can cause significantly greater damage and even death of susceptible host palms (NGIA,
1998). In the Northern Territory, where the sugarcane weevil borer is absent, the impact is low
and there is no effort to manage D. frumenti.
Picture by Francesco Salomone. Damage caused by D. frumenti on young palms, Maspalomas, Gran Canaria
December 2000
Control
Control of D. frumenti is difficult because of its cryptic nature.
Cultural control
Excessive pruning, shaving of the trunk, inadequate fertilization and watering are believed to
help the establishment of the species (Salomone & Caballera Ruano, 2008). Pruning should be
avoided.
NGIA (1998) recommended several cultural control methods against D. frumenti. These
include removing and destroying old and dead fronds to reduce breeding sites and adult hiding
places, protecting cut surfaces with an acrylic paint (or tar, Lever, 1969), and covering
adventitious roots at the stem base with soil to prevent infestation as earlier recommended by
Lever (1969).
Chemical control
There are no registered insecticides for this weevil in northern Queensland (NGIA 1998), but
a chemical applied against another weevil pest there (chlorpyrifos) would also reduce the
numbers of D. frumenti.
It is likely that persistent contact chemicals would reduce D. frumenti attack to the base of
palms if applied as a protectant insecticide as recommended by Lever (1969). Protecting the
rachis of the frond and the frond bases would be more difficult even if such a chemical was
registered for that use. Salomone Suárez et al. (2000a) have proposed several studies to test
the efficacy of chemical treatments to D. frumenti and the possible interactions between this
weevil and pathogens which may be involved in the serious damage and death of palms in the
Canary Islands.
A patent disinfection device for fumigating palms infected with D. frumenti has been
submitted for assessment (Roca Michavila, 2006).
Trapping
Salomone & Ruano (2008) have outlined a project to determine whether this species produces
an attractant pheromone or if attractant bait for the weevil could be developed. If the studies
produce acceptable results, then the pheromone or bait could be integrated into a trap for the
palm weevil borer.
Biological control
Several biological agents are known to attack D. frumenti but are unlikely to provide effective
control if chemical treatments are also used. Vanderplank (1953) reported that in Tanzania,
two species of ants, Anoplolepis custodiens and Oecophylla smaragdina would prey on this
beetle in coconuts. Both adults and larvae of the histerid beetle Plaesius javanus and larvae of
the rhagionid fly Chrysophilus ferruginosus are predators on D. frumenti larvae (Lever, 1969;
Kalshoven 1981). Giblin-Davis (2001) (citing Lever, 1979) claimed that the same generalist
predators of the sugarcane weevil borer would also attack D. frumenti. Lever (1969) reported
that 40% of D. frumenti larvae were found to be parasitised by a braconid wasp Spathius
apicalis. These species are not recorded in the EPPO region. It is possible that if these species
or other generalist predators are present in an area, that they may maintain some control over
this beetle pest and similarly, natural enemies of closely allied species such as D. taitense
could be tested and perhaps introduced against D. frumenti (Salomone Suárez et al.,2000b).
Phytosanitary risk
The most likely pathway for D. frumenti to enter the EPPO region is through the import of
palm plants for planting, derived from countries where D. frumenti occurs.
The example of another serious palm borer Rhynchophorus ferrugineus that has recently been
introduced to Spain and is currently spreading in the Near East has shown that this type of
insect is likely to be moved unnoticed on palm material.
PHYTOSANITARY MEASURES
D. frumenti is listed in the Moroccan Bulletin official n°5022 of the 18 July 2002 as a pest for
which introduction is prohibited.
On 12 April 2002, the Republic of Korea sent a notification to the World Trade Organization
Committee on Sanitary and Phytosanitary Measures stating that “as the result of Pest Risk
Assessment (PRA), […] the Ministry of Agriculture and Forestry is proposing the addition of
24 species of quarantine pests such as Xylophilus ampelinus, Diocalandra frumenti,
Lecanoideus floccissimus, etc. for susceptible host plants” (PMC (2002) G/SPS/N/KOR/111).
To be completed after PRA
ACKNOWLEDGEMENTS
This datasheet has been prepared by the EPPO Secretariat on the basis of a text prepared by Stuart
Smith from the Department of Regional Development Primary Industry, Fisheries and
Resources in the Northern Territory of Australia.
BIBLIOGRAPHY
Anonymous (2008) CABI distribution maps of pests, Diocalandra frumenti, Map no. 249.
CABI, Wallingford, UK.
AVA (2006) AgriFood and Veterinary Authority of Singapore. p.40 of Annual Report
2005/06. The coconut palm weevil, Diocalandra frumenti Fabricius was found in a first
report on Metroxylon sagu in Singapore.
http://www.ava.gov.sg/NR/rdonlyres/0676D1EB-C401-4038-9D8D84A01B52DD27/11973/AVAAR0506corporate.pdf. Website visited November 2008.
Bulletin officiel n° 5022 du 7 joumada I 1423 (18 juillet 2002) Maroc
http://www.mcinet.gov.ma/mciweb/baseslegales/200.pdf
http://www.eppo.org/ABOUT_EPPO/EPPO_MEMBERS/phytoreg/originals/PRF-MA02rev.doc
Giblin-Davis RM (2001) Borers of palms. In: Insects on palms. Edited by FW Howard,
Moore, D, Giblin-Davis RM, Abad, RG. CABI Publishing, Wallingford, GB, 287-288.
González Núñez M, Jiménez Álvarez A, Salomones F, Carnero A, Del Estal P, Esteban Durán
JR (2002) Diocalandra frumenti (Fabricius) (Coleoptera: Curculionidae), nueva plaga de
palmeras introducida en Gran Canaria. Primeros estudios de su biología y cría en laboratorio.
Boletín de Sanidad Vegetal Plagas 28(3), 347-355.
Hill DS (1983) Diocalandra frumenti. In: Agricultural insect pests of the tropics and their
control. 2nd Edition. Cambridge University Press, Cambridge, UK, pp. 478-479.
Howard FW, Moore D, Giblin-Davis RM & Abad RG (2001) Insects on palms. CABI
Publishing. 400 pp.
Kalshoven LE (1981) Pests of crops in Indonesia. 2nd Edit., Van Hoeve Jakarta 1981. 701 pp.
Lepesme P (1947) Les insectes des palmiers. Paul Lechevalier (Edit.) Paris. 904 pp.
Lever RJAW (1979) Pests of the coconut palm. FAO Agric. Studies No 77. FAO Rome. 190
pp.
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attacking ornamental palm seedlings. Bulletin of Taichung District Agricultural Improvemnet
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descriptions of a new Genus and five new species. Esakia 12, 103-118.
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Issue no 1998/02.
Getting control of weevil borers and leaf beetles in palms.
hhtp://www.ngia.com.au/np/pdf/98no02.pdf
PMC (2002) G/SPS/N/KOR/111
http://www.ipfsaph.org/cds_upload/kopool_data/WTOSPSNF_0/en_nkor111.doc
http://www.ipfsaph.org/cds_upload/kopool_data/WTOSPSNF_0/fr_nkor111.doc
Roca Michavila J (2006) Method for the curative treatment of Diocalandra frumenti
infestations.
http://www.wipo.int/pctdb/en/wo.jsp?WO=2007099191&IA=WO2007099191&DISPLAY=S
TATUS
Salomone F, Cabellero Ruano M (2008) New pest for Phoenix canariensis Hort. Ex. Chab. in
its original habitat, the Canary Islands. Situation report. 2 pp.
Salomone Suárez F, Gonzalo Bartolomé O, Hernández Hernández J, Rodríguez Rodríguez R,
Muñoz Carpena R (2000a) Identificación y propuestas de control de factores bióticos y
abióticos que producen depresión y mortalidad de palmeras naturales o implantadas en
Canarias. Granja (eds. Cabildo de Gran Canaria) 7, 9-13.
Salomone Suárez F, Carnero Hernández A, Marrero Ferrer M, González Hernández A
(2000b). Presence in the palearctic zone of Diocalandra frumenti Fabricius, (Coleoptera,
Curculionidae). Boletín de la asociación Espaňola de Entomología 24, 263-264.
Vanderplank FL (1953) Causes of coconut nutfall and gumosis. Nature 172, 315 – 316.
Zimmerman EC (1993) Australian Weevils (Coleoptera: Curculionidea). Vol. III: 99-102.
CSIRO Publications, Australia.