Duration: 10/01/2025 to 09/30/2027

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Coconut Rhinoceros Beetle (CRB) is a large scarab beetle native to Southeast Asia and a damaging pest of palm species, most notably coconut palm (Cocos nucifera). CRB adults damage palms, particularly younger ones, by boring into the center of the crown, where they injure the young, growing tissues and feed on the sap. The damage can significantly reduce coconut production, and tree mortality can occur when CRB destroys the growing tip. Coconut palms are an important source of food and fiber, as well as part of many tropical islands’ ecosystems, landscape and nursery industries, and iconic scenery. Coconuts are highly valued by residents and tourists as an important economic botanical in Palau, the region and the world.  On low lying islands, especially atolls, with little to no aquifer they are the only emergency source of hydration during droughts and severe weather events and are therefore not only the tree of life and tree of survival in this era of climate change.

Heavy damage by CRB throughout the Pacific was documented after WWII, which was addressed by the development and release of a Oryctes specific nudivirus (OrNV) which effectively controlled the population expansion in the region.  However, a dire call for an emergency response to a new variant of rhinoceros beetle (CRB-G, first detected in Guam) that has invaded the Pacific Islands since 2007 is more critical than ever before due to its resistance to the original OrNV. This highly damaging new variant has invaded Guam, Papua New Guinea, Hawaii, Palau and the Solomon Islands within the last 10 years and is believed to have significantly decreased populations of palms, as it continues to spread.  CRB has been documented to cause damage in other palms as well, such the beetle-nut palm (Areca catechu), and the oil palm (Elaeis guineensis) reaching outbreak proportions during periods with heavy rainfall and in areas with decomposing organic matter, ideal conditions for their reproduction. A dire call for an emergency response for a new variant of rhinoceros beetle (CRB-G) that has invaded the Pacific Islands since 2007 is more critical than ever before. The fact that Pacific Island countries and territories have a diversity of native and introduced palm species and coconut being the pre-eminent amongst them as fundamental for food security, construction material and as an icon for tourism in the Pacific has made even more important for the region to curtail the damage caused by CRB-G. This highly damaging new variant has invaded Guam, Papua New Guinea, Hawaii, Palau and the Solomon Islands within the last 10 years and killed 70 – 80 percentage of palms, as it continues to spread. Throughout the region the presence of the CRB-Guam biotype has shown evidence of severe to catastrophic levels of damage (50 – 90 %) as compared to the CRB-Pacific biotype which, with virus biocontrol, only causes light to moderate damage (10 – 50%) in ‘hot spots’ with uncontrolled breeding sites.  Palau has had moderate damage despite the presence of both biotypes and sever weather may result in a resurgence of the CRB because of increased breeding sites. It is resistant to the biocontrol virus and is literally killing palms as it advances its invasion. The beetle is invasive and has the potential of wiping out palms if proper control measures are not initiated, except in isolated resort environments where that have reduced damage by nearly 90%.  Previous damage assessments show a slight rise in damage, which was more severe after sequential typhoons in 2012 and 2013 that increased breeding sites for the beetle. The damage was at its worst in 2015 with nearly every tree in Peleliu showing beetle damage and has affected the whole of Palau including the Northern and Southern Atolls. The beetle is also posing imminent invasion threats to other islands and countries with damage assessment of up to 75% of trees and therefore requires urgent attention. This project aims to address the issue of coconut damage in Palau, to prevent further damage and remediate areas that are most vulnerable to the damage, such as outer lying atolls, because food and hydration in drought is solely provided by coconuts. The protection methods such as trapping and prevention will be tested on islands to gauge effectiveness and concurrently, biocontrol will be assessed and released to gauge effectiveness.

Statement of Issues and Justification

The coconut rhinoceros beetle (Oryctes rhinoceros) (CRB) is a scarab beetle that is naturally found in the coconut-growing regions of Asia that range from Pakistan to Indonesia (Hinckley, 1973). CRB has been accidentally introduced to several islands in the South and West Pacific such as, Western Samoa, Fiji, Papua New Guinea, Guam and Palau (Gressitt, 1953). This beetle has been observed to cause damage to crops such as oil palms, bananas, pineapples and, most significantly, coconut palms (Cocos nucifera) (Hinckley, 1973). The adult CRB bores into the crown of the coconut palm to feed on the sap. As the beetles feed, they are eating through the premature leaves still developing within the crown of the coconut. As the leaves grow and emerge, they are left with very distinct v-shaped cuts that reduce the tree’s photosynthetic productivity. Prolonged infestation of CRB would lead to the death of the tree once the CRB bores through the apical meristem, the point from which the coconut grows (Moore et. al., 2015).

The coconut palm tree is highly regarded in the Pacific often referred to as the "tree of life (Stapley, 1973)." The coconut is culturally and economically important to the people of the Palau and the Pacific and therefore the attempt to find a means to reduce and manage CRB populations on these islands intensified. In the mid 1950s through the 1960s extensive surveys were carried out to find potential diseases of Oryctes spp. in places that hosted this pest. Rather than surveying the areas where the CRB has invaded and caused the most damage, researchers focused in areas where they are naturally found in order to find an effective biological control agent (Huger, 2005). Most of the work in the Pacific islands especially most effected places like Guam and Solomon Islands has been focused on sanitation, or cleaning of debris and methods of capturing beetles as they attack trees; the focus on biocontrol has been limited due to time frame and capacity for virus identification and virulence test in our region.  With the discovery of Guam biotype with virus in Palau, as well as the isolation and introduction of it to pure resistant strains of CRB there is a need for a focused efforts, through this project, to identify a multiple virulent strains of the OrNV virus and test them on varieties across affected locations.

This project would focus initial work in Palau while working in collaboration with agriculture and CRE components across the Pacific for a systematic trapping and isolation of virus variants for development of long-term control practices. 

Why focus in Palau?

Multiple biotypes of the CRB are in Palau including the OrNV resistant and multiple others allowing for the import of other biotypes for study as less of a risk. Damage Assessment Surveys were conducted on coconut trees in several locations in all of the 16 states in Palau since 2014. These surveys were made to determine the amount of damage done by the beetles and can offer baseline support for control mechanisms. Specialized traps were used along with manual searches through debris to collect and determine distribution of CRB-G as well as incidence of Oryctes Nudivirus (OrNV) infection and have been studied, shared and assessed with partner institutions. The results of the Damage Assessment Surveys show slow recovery/reduced damage in coconut tree fronds. Furthermore, analysis of biotype and viral detection show a very high rate of infection of all CRB with the nudivirus (CRB: 92%; CRB-G: 83%). The reduced tree damage and high rate of infection of the beetles, as well as visual assessments of CRB samples gut damage, lead to the preliminary conclusion that the OrNV in Palau CRB is virulent and was proven for one strain, but requires more in depth sampling, identification and growout for testing. Further large scale and regular sampling of CRB for biotype mapping and virus isolation and identification will allow for development of biocontrol cocktail to be tested and introduced for control for the region and the world.  Palau is the perfect sight for focused research to identify and purify a virulent strain(s) of OrNV that can be used for biocontrol for CRB.

Literature review/previous work

Rhinoceros beetle, Oryctes rhinoceros (L.) is one of the major pests of coconut in India and other coconut producing countries causing direct and indirect losses to the crop. Ramachandran et al. (1963) reported a crop yield loss of 5.5 to 9.1 per cent due to rhinoceros beetle attack (Rao et.al 2018). CRB has been accidentally introduced to several islands in the South and West Pacific such as, Western Samoa, Fiji, Papua New Guinea, Guam and Palau among several others (Gressitt, 1953). This beetle has been observed to cause damage to crops such as oil palms, bananas, pineapples and, most significantly, coconut palms (Cocos nucifera) (Hinckley, 1973). Prolonged infestation of CRB would lead to the death of the tree once the CRB bores through the apical meristem, the point from which the coconut grows (Moore et. al., 2015). Taxonomists later placed these in to a new virus family, Oryctes, to accommodate the specificity of this particular virus that became known as Oryctes baculovirus. In 1997 it was officially referred to as the Oryctes nudivirus (OrNV). The OrNV was purposely introduced in Palau in the 1970s that helped reduce CRB populations (Jackson, 2009). However, in 2007 a new CRB biotype – CRB-G was detected in Guam and then found throughout the Pacific in subsequent assessments (Marshall 2016). This CRB-G has been observed to be resistant to all the known isolates of the biocontrol OrNV (Moore, 2015). Since its detection, this biotype has been spread to Port Moresby in Papua New Guinea, Hawaii, the Solomon Islands, and Palau (Marshall 2017). As of now, there are two known biotypes of CRB. This new CRB-G and the previously known CRB, susceptible to the OrNV, which is referred to as CRB-P. Port Moresby and Palau are the two places in the Pacific where both biotypes, CRB-P and CRB-G, are present (Moore, 2015).  Distribution of beetle biotypes in Palau in both categories non-G type and G-type (Etebari, 2021) is shown in Figure 1.

Goal

Control current infestation of Coconut Rhinocerus Beetle in Palau and prevent further devastation of valued coconut crops through sanitation, trapping and focused effort on biological control that would be effective for the region.

Objectives

Procedures and Activities

Hypothesis

Proper sanitation methods for breeding sites, systematic responses to the resistant CRB-G in Palau are effective methods of slowing damage, but biological control agents such as a virulent OrNV virus is the only long term solution to CRB control for Palau and other affected locations in the region.

Methodology

Objective1. Standardize damage assessments in Palau with high throughput methodology.

Methods:

Sites throughout Palau that have been previous identified will be assessed; CRB damages will be evaluated on up to 25 randomly selected coconut palm trees at each site. A scale of 0-4, developed by SPC (Secretariat of the Pacific Community), will be used for evaluations for top 4 fronds and entire tree: 0 = no damage, 1 = 1-29% removed (light), 2 = 30-49% removed (moderate), 3 = >50% removed (severe), 4 = dead palm.  GIS locations of all assessment sites will be recorded, and a map will be produced as shown below from past surveys (MAP 1).

Furthermore, Annotated drone or drive by video CRB damage surveys with online-based software (https://github.com/opencv/cvat) will be trialed for a more high throughput methods and compared to current damage assessment statistics.

 

 

Objective 2. To develop a systematic response system to coconut rhinoceros beetle in Palau as a pilot project for the region.

 

Methods:

CRB trapping (netting mulching and solar and pheromone traps), breeding site sanitation and laboratory assessment.

Netting/ mulching

Netting has been quite successful for private hotel, Palau Pacific Resort, reducing damage from an average of 2.5 to 0.2 (0-4 scale) over 1 year (unpublished assessment). We will test these methods at various study locations in Palau.  Our target states are where trees show significant CRB damage, such as in Babeldaob (largest land mass in Palau), Koror (business and population center), including the uninhabited limestone Rock Islands, Kayangel the northern most atoll island state and the Southern most atolls in the Southwest.  Net will be covering the crowns of coconut trees to capture the beetles before they can damage the coconut tree as well as at the base of trees to capture beetles crawling up the tree and samples will be collected and assessed.

Traps with solar and pheromone lures

Traps with Solar lights and Pheromone lures have been effective in trapping male and female beetles in the region (reference).  These collections have been used to study biotype and OrNV infection.  This method will be continued in Palauwith modification based on supplies available and will be checked regularly as well to have a standard collection method for comparison for the region.  This is important for standardized review of effectiveness of virus distribution.

Breeding site sanitation

For CRB trapping, possible breeding site around the area will be examined. If potential breeding sites, such as green waste and unidentified mulch are found, netting will be used to cover the mulch piles. This process will prevent the adult beetles in these breeding sites from flying out to the coconut trees as well as capturing samples and reviewing population subsets.  Sites will be monitored and then sanitized per green waste management protocols that have already been developed at the Solid Waste Management site. Furthermore, larvae will be collected from sites for analysis of biotype and virus content.

 

Objective 2.  Identify and evaluate endemic biocontrol agents (field collection dissections and growth chamber and viral assay)

 

Methods:

Any samples collected will be dissected in the lab and DNA will be extracted from the legs or gut of each sample using DNeasy Blood and Tissue Kit by Qiagen, to undergo further DNA analyses to determine the biotype. To determine the distribution of CRB biotypes the DNA samples from the CRB samples collected undergo a polymerase chain reaction (PCR). We use a restricted fragment length polymorphism (RFLP) assay. This is a two-part assay where, first, we introduce the following primers C1-J-1718Oryctes (5’-GGAGGTTTCGGAAATTGACTTGTTCC-3’) and C1-N-2191Oryctes (5’-CCAGGTAGAATTAAAATRTATACCTC-3’) to amplify the CRB’s cytochrome oxidase I (COI) gene. The expected band size after running the PCR sample through a gel electrophoresis is 523 base pairs as seen in Figure 2. The first lane is a negative control. Lanes labeled 1-6 are some samples that have gone through the PCR assay. The yellow “+” indicates a positive sample for CRB-P and the red “+” is a positive control for CRB-G. The ladder used for the visualization was the GeneRuler 100bp.

The second part of the assay is to introduce the MSE1 restriction enzyme. After digestion we can better distinguish the CRB-P from CRB-G. The expected band size for CRB-G is 253. CRB-P sample will show banding at 181bp and 72bp.  Lane 3, in Figure 3, is a visual representation of CRB-G after digestion.

The third part of the study is to test for the presence of the CRB viral biological control, OrNV. Using the same samples collected, these samples undergo a PCR for OrNV detection where we introduce the following primers OrV15a (5’ATTACGTCGTAGAGGCAATC-3’) and OrV15b (5’ATGATCGATTCGTCTATGG-3’) to amplify the CRB’s glycoprotein. The expected band size is 945bp as shown in Figure 4. For the visual representation we will use the GeneRuler 1kb as a comparative ladder.

Identification is necessary to find populations of separated biotypes, but then after that infected beetles need to be assessed for virulence. OrNV infection appears to induce particular morphological deformations such as milky and swollen digestive system filled with organic matter in the abdomen of the CRB. Therefore, dissection of the all field-collected specimens will be performed to screen the pathogenic agents for CRB. If the specimen with symptom is discovered, we will isolate and propagate the pathogen for the further characterization.  This will require Palau-based dissection and growth facilities, which will also be set up during the initial phase of the project development with partners from Hawaii, Japan and Germany and will have regular exchanges and monitoring.  Furthermore, as it is evident that a viral strain exists in Palau that infects the resistant strain; we would create viral growth, replication chambers: with tandem viral purification, identification and storage preparation for distribution to the region.   Screening the local biocontrol agents specifically for CRB-G is necessary to control the CRB population; and after development of Palau’s biological control this method can be replicated for each region, possibly in the form of a storage and infection facility; hence each station will be able to receive and store the virus as well as ability to infect CRB in their own country.

Isolated varieties will be shared across facilities for there own testing and/or varieties of beetles can be brought in from outside sites for testing on various viral strains and effective strains can be provided to sites directly or in infected beetles from those sites for release.

Objective 4. Outreach

In order to provide outreach and education about the CRB in the region three focused strategies will be used: school education; community outreach; and public outreach with the support of the focal points connecting with community-based association as well as local NGOs and traditional leadership. The overall goal is to raise awareness, understanding and call action to the threats of the CRB to coconut trees, an important cultural plant species and cash crop.  This model can be adapted at each site for appropriate dissemination as seen fit by local extension agents from the respective island communities.

Methods:

1. School education will consist of working with the environmental and science clubs at the only local high school and the vocational college; members of these clubs as well as member of the newly established, local, PAIR Club summer program will develop awareness materials and presentations. The students will visit schools and deliver presentations as well as run field trips to show damage caused and how to reduce this damage. PAIR program will be the operations base for the laboratory and assessment team.
2. Community outreach will consist of working with: local companies or individuals that utilize coconuts for economic subsistence, such as producers of coconut oil and other coconut-based products; and resorts that use them as ornamentals. The work will consist of training techniques and taskforce development to deploy response system throughout the region and gauge its effectiveness.
3. Public outreach will consist of activities that include awareness campaign to all sectors in the government and community action groups through support from PIF partners; materials, training and assistance will be provided to assigned individuals with standard control/assessment techniques. Local media will be used for information dissemination and public awareness talk shows that will be question and answer format to allow for more public engagement. Furthermore, a website and social media will be established for cross-regional information dissemination and streamlined communication.
4. Global outreach will consist of providing all information to Pacific Island Forum leadership for dissemination within the island communities and international communities for support and control globally to prevent further outbreak.

 

Expected Outcomes and Impacts

Projected Participation

View Appendix E: Participation

Educational Plan

Target audience

Study Topics	Target Audience
On the ground Control Methods	Farmers, gardeners, hobbyists, village leaders, extension agents, bureau of agriculture biocontrol, hotels and tour sites operators
Biological Control	Research scientist, research assistants, schools, teachers, students, extension agents, bureau of agriculture and biocontrol
Outreach	Farmers, gardeners, hobbyists, village leaders, schools, teachers, students, extension agents, ministry of state and education.
Statistical analyses	Teachers, students, extension agents, research assistants

External/Internal linkages

Internal Linkages: Bureau of Agriculture (Palau), Customs and Border Control (Palau), Pacific Academic Institute for Research, Palau Governor’s Association

External Linkages: University of Guam; Pacific Community; University of Hawaii, Department of Agriculture; Tokyo University of Agriculture and Technology, Institute of Agriculture; Hokkaido University, Department of Agriculture.

Organization/Governance

The recommended Standard Governance for multistate research activities include the election of a Chair, a Chair-elect, and a Secretary. All officers are to be elected for at least two-year terms to provide continuity. Administrative guidance will be provided by an assigned Administrative Advisor and a NIFA Representative.

Literature Cited

Bedford, G. O. (2013). Long-term reduction in damage by rhinoceros beetle Oryctes rhinoceros (L.)(Coleoptera: Scarabaeidae: Dynastinae) to coconut palms at Oryctes Nudivirus release sites on Viti Levu, Fiji. African Journal of Agricultural Research, 8(49), 6422-6425.

Chalapathi Rao, N., Snehalatharani, A., Nischala, A., Ramanandam, G., & Maheswarappa, H. (2018). Management of rhinoceros beetle (Oryctes rhinoceros L.) by biological suppression with Oryctes baculovirus in Andhra Pradesh.

Etebari, Kayvan, Hereward, James, Sailo, Apenisa, Ahoafi, Emeline M., Tautua, Robert, Tsatsia, Helen, Jackson, Grahame V. and Furlong, Michael J., 2021, Examination of population genetics of the Coconut Rhinoceros Beetle (Oryctes rhinoceros) and the incidence of its biocontrol agent (Oryctes rhinoceros nudivirus) in the South Pacific Islands. Current Research in Insect Science: V1;pgs 100015 ISSN: 2666-5158 DOI: https://doi.org/10.1016/j.cris.2021.100015

Gressitt, J. L. (1953). The coconut rhinoceros beetle (Oryctes rhinoceros) with particular reference to the Palau Islands. The Coconut Rhinoceros Beetle (Oryctes rhinoceros) with particular Reference to the Palau Islands., (212).

Hinckley, A. D. (1973). Ecology of the coconut rhinoceros beetle, Oryctes rhinoceros (L.)(Coleoptera: Dynastidae). Biotropica, 111-116.

Huger, A. M. (2005). The Oryctes virus: its detection, identification, and implementation in biological control of the coconut palm rhinoceros beetle, Oryctes rhinoceros (Coleoptera: Scarabaeidae). Journal of invertebrate pathology, 89(1), 78-84.

Marschall, K. J. (1970). Introduction of a new virus disease of the coconut rhinoceros beetle in Western Samoa. Nature, 225(5229), 288.

Marshall, S. D., & Moore, A. (2016). A New Coconut Rhinoceros Beetle Biotype Threatens Coconut and Oil Palms in Southeast Asia and the Pacific.

Marshall, S. D., Moore, A., Vaqalo, M., Noble, A., & Jackson, T. A. (2017). A new haplotype of the coconut rhinoceros beetle, Oryctes rhinoceros, has escaped biological control by Oryctes rhinoceros nudivirus and is invading Pacific islands. Journal of Invertebrate Pathology.

Moore, A., Jackson, T., Roland, Q., Bassler, P., & Campbell, R. (2015). Coconut rhinoceros beetles (Coleoptera: Scarabaeidae) develop in arboreal breeding sites in Guam. Florida entomologist, 98(3), 1012-1014.

Stapley, J. H. (1973). Insect pests of coconuts in the Pacific region. Outlook on Agriculture, 7(5), 211-217.

Tanaka, S., Harrison, R.L., Arai, H. et al. Confirmation of Oryctes rhinoceros nudivirus infections in G-haplotype coconut rhinoceros beetles (Oryctes rhinoceros) from Palauan PCR-positive populations. Sci Rep 11, 18820 (2021). https://doi.org/10.1038/s41598-021-97426-w

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