Brontispa longissima invaded Cambodia around 2001. Of the total 12.3 million coconut trees, 1.95 million trees or 16 percent were killed by B. longissima, 7.2 million trees or 58 percent were attacked. Due to lack of information about this invasive species, the country mounted an extensive chemical control campaign, incurring much expense but with negligible results. The representative at the meeting indicated the need for sustainable management of B. longissima in Cambodia.
The coconut leaf beetle was found in Hainan, Guangdong and Taiwan provinces, but the worse affected areas are in Hainan province.
In Hainan province, 11 species of host palm trees such as Cocos nucifera, Areca catechu, Archontophoenix alexandrae, Roystonea regia, Washingtonia fllifera, Hyophorbe lagenicaulis, Washingtonia robusta, Liviston chinensis and Chrysalidocarpus lutescens were recorded. The major host plant is Cocos nucifer. Dry periods favour the development of Brontispa populations. The long distance spread is aided by human activities.
Two biological agents, Asecodes hispinarum and Metarhizium anisopliae, are being intensively tested to manage this pest and promising results have been reported. Larger releases, especially of A. hispinarum, are being planned together with arrangements for monitoring its impact.
Brontispa longissima is one of the major pests in several provinces of Indonesia. There are three potential natural enemies for controlling B. longissima, namely: pupal parasitoid (Tetrastichus brontispa), entomopathogenic fungi (Metarhizium anisopliae var. anisopliae and Beauveria bassiana). T. brontispa has an important role as pupal parasitoid both under laboratory and field conditions. Percent parasitism of pupa under laboratory and field conditions ranged from 76.7 to 87.0 percent and 35.71 to 73.56 percent, respectively. Pathogenicity of M. anisopliae var. anisopliae and B. bassiana were examined under laboratory and field conditions. The results showed that these fungi could infect both larvae and adults of B. longissima.
Brontispa longissima was reported in Lao PDR from 2001. A survey showed that six villages in two provinces are faced with damage from the coconut beetles. These included Namthon village in the Pakkading district of Bolikamxay province and the villages of Novilay, Vangboangtai, Vangboangnua, Fouang and Nabo in the Sepon district of Savannaket province.
With support from FAO, national plant protection staff are learning to rear Brontispa parasitoid in Viet Nam and will benefit from the experiences of classical biological control there. A. hispinarum will be released soon.
Coconut leaf-eating beetles, particularly Plesispa reichei, have become important pests in Malaysia. Frequent and sporadic infestations of P. reichei beetle have been reported on the coconut and ornamental palms throughout the country. As this pest was relatively unknown previously, little was known about its biology and ecology and effective control measures. More collaborative efforts among affected countries are required to develop effective short and long term control measures of this pest.
It is most probable that the Brontispa infestation originated from adult or immature stages of the pest that were concealed in ornamental palms imported in 1999 from nurseries in Malaysia and Indonesia, as Brontispa is believed to be endemic to the Indonesian and Papua New Guinean region.
A survey confirmed that the beetle had spread from the known distribution range (Fenfushi, Tholhufushi, Nalaguraidhoo, Dhiffushi, Maamigili and Ariyadhoo) to islands further eastwards (Dhidhdhoo, Dhidhoofinolu and Dhigurah). The extent of infestation on Dhidhdhoo village indicated that the beetle had been present there at least for one year. Few infested palms were found on Dhidhoofinolhu and Dhigurah and it appears that the beetle reached the island at a later stage.
As in Cambodia, insecticides were recommended prior to introduction of biological control agents. While this measure afforded some relief, these were both expensive, polluting and provided only short term control of the pest. The parasitoid A. hispinarum was imported to the Maldives from Viet Nam. It was transferred to a semi quarantine laboratory at Sun Island resort for quarantine, mass rearing and field release to all infected islands of the Maldives. About 230 000 parasitoids have been released. Following its initial release in February 2004, the larval parasitoid Asecodes hispinarum now appears established on Sun Island. Parasitoid establishment on the inhabited islands of Maamigili and Fenfushi appears more difficult, despite the release of large numbers of adult parasitoids and mummies on both islands.
Brontispa longissima is a serious pest of coconut palms and it had been known to occur in Myanmar since early 2004. Plant protection teams of two states and four divisions have been assigned to conduct the specific survey for Brontispa with available support. There is an urgent need to build national capacity to address the problem of invasive pests to ensure sustainable development.
P. reichei is a minor coconut pest and B. longissima is not yet reported in Sri Lanka.
Brontispa represents a threat to the coconut industry of the southern and central parts of Thailand with US$30 million production and 50 000 smallholder farmers. It is also a threat to the tourist industry of Koh Samui and Koh Pa-ngan.
Damage caused by Brontispa was first recorded in Narathiwas province, the border area near Malaysia, in 2000. Heavy infestation was first reported in February 2004 in southern provinces including Surat Thani (Samui Island and Pa-ngan Island) and Prachuap Khiri Kan.
It is reported that the total areas hit by the coconut beetle outbreaks amounted to 7 229 hectares.
Both the Department of Agriculture (DoA) and Department of Agricultural Extension (DoAE) are rearing Asecodes hispinarum from a shipment received from Viet Nam on 25 August 2004.
Other biological control agents are being reared by DoAE but, based on the results from Viet Nam, it would be more appropriate to educate farmers about the positive impact of A. hispinarum. Other biological control agents will be useful to educate farmers about biological control.
Brontispa longissima was first detected in the Mekong Delta region in 1999. Despite extensive use of chemical insecticides to control this pest, the beetle spread and incurred losses estimated at US$17.8 million to the coconut industry by 2002. Indeed, the cost of insecticide use was estimated at US$722 323. These were not only expensive, they caused much damage to the environment and further exacerbated the problem of the Brontispa outbreak. The beetle continued to spread to new areas.
With the support of FAO, A. hispinarum was introduced from Western Samoa in June 2003 and these were reared under quarantine conditions and later released into the field in August 2003. By 2004, the parasitoid was released and became established in 15 provinces in South and Central Viet Nam. The parasitoids spread at the rate of 5-8 km in two months and, within four months, 60-90 percent recovery of palms was observed.
A quick economic analysis covering a time frame of 30 years puts a return of US$3 000 for every dollar invested. It is concluded that classical biological control of Brontispa longissima can be quickly, effectively and sustainably controlled by the introduction and releases of Asecodes hispinarum. However, this means that there is an urgent need to enhance the capability of national programmes in the areas of quarantine, biological control and IPM. In this respect, every country has to adhere to the guidelines contained in the International Standards for Phytosanitary Measures (ISPM) #2 and #3[1]. It is necessary that countries in the region strengthen their capability in addressing this issue of invasive species and ways and means to resolve them through sustainable methods that protect the biodiversity and ensure poverty reduction.
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[1] International Standards for
Phytosanitary Measures (ISPM) #2 and #3 can be found in this report as Annexes 8
and 9. |
