W509: Coconut Rhinoceros Beetle-Multistate Project Concept

(Rapid Response to Emerging Issue Activity)

Status: Active

W509: Coconut Rhinoceros Beetle-Multistate Project Concept

Duration: 05/24/2023 to 09/30/2025

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

The Pacific region is usually facing similar challenges, whether it be food security, development, or disease management. This connectivity of challenges and relative isolation of Pacific Islands make multi-state program a good mechanism for addressing these challenges.  A specific example of the Coconut Rhinoceros Beetle issue demonstrates this perfectly.

There have been ongoing exchange and collaborations with partners in Hawaii, Guam, CNMI, and other Pacific islands in Micronesia (Palau, Federated States of Micronesia and Marshall Islands) on an effective biological and physical control protocols against Coconut Rhinoceros Beetle.

Coconut Rhinoceros Beetle (CRB) is a large scarab beetle native to Southeast Asia and a damaging pest of palm species, most notably the coconut palm (Cocos nucifera).  CRB adults damage palms, particularly younger ones, by boring into the crown of the palm causing irreparable damage to growing tissue as they feed on the sap.  The damage can significantly reduce coconut production, and with multiple beetles result in tree mortality. The tree of life or coconut palm is the most important plant in the Pacific providing food, hydration and oil, as well as material for shelter and much more. The coconut tree is a major fixture in tropical islands' ecosystems, used in landscaping, nursery industries, and unique scenery.  Coconuts are highly valued by community residents and tourists as an important economic botanical in the world. This tree is the fundamental for food security, construction material, and as an icon for tourism in the Pacific.

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. 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 the beetle-nut palm (Areca catechu), reaching outbreak proportions during periods with heavy rainfall and in areas with decomposing organic matter, ideal conditions for their reproduction. 

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 incurred moderate damage despite the presence of at least two (2) genetically distinct biotypes. For this insect species, the previously released OrNV maintains its effectiveness growth and reproduction.  The CRB-G biotype is believed to be resistant to the strain of virus that it hosts, or the virus itself has lost virulence due to some yet-explained mechanism.  Furthemore, OrNV variants were found to among different CRB biotypes. These findings have led to a new research questions in determining where this mutation in host or virus can be detected.  A corollary is that there may be a strain of OrNV that will successfully infect and suppress the CRB-G biotype under controlled conditions, and simultaneously in different locales where it occurs (e.g., Guam, Hawaii, CNMI, etc.).  Palau offers an environment where the multiple variants of the CRB breed, including the resistant variant, and where the OrNV exists in situ and was first found to transmit to the CRB-G type.

This project aims to incorporate collaborative efforts in laboratory and field experimentation to address the issue of CRB-related damage to crops and livelihoods in insular areas of the tropics.  The goals are to 1. use genetic analysis to test for and identify an effective biocontrol agent in OrNV strains, 2. demonstrate proven field suppression methods such as trapping and prevention, and 3. facilitate exchange between islands that share similar CRB issues and concerns.

Due to the area of damage caused by the Coconut Rhinoceros Beetle (CRB) and the collaborative research and extension effort necessary to protect palms from continuous damage, a multi-state project would be an ideal mechanism for concentrated effort in plant protection. The Pacific RISA with USDA have identified CRB as one of the most invasive species with major consequences to subsistence and economic livelihood throughout the tropical and subtropical regions.

The most affected areas are the Pacific and Southeast Asia and control and prevention oof the CRB spread has been at the forefront of research across Pacific Land Grant institutions.  American Samoa, Hawaii, Guam, Palau and FSM have been working with colleague from across the globe to address this issue.  A multi-state project initiated in Palau including all the above institutions with support from other larger land grant institution with plant protection specialists would be the ideal project for enhancing collaboration for effect protection of crops in the Pacific.

Why Palau?

Multiple biotypes of the CRB exist in Palau including the resistant straing of “CRB-G”. Permanent plots have been established for tree frond damage assessment in all of the 16 states in Palau since 2016 including collection of beetles for biotype and viral assessment to determine distribution versus damage. 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.  Further assessment is necessary but immediate focus of all parties should be made to identify and test virulence of OrNV in Palau in order to control CRB for the region.


Types of Activities


  1. Evaluate the systematic response to coconut rhinoceros beetle in Palau as a pilot project for the region.
  2. Identify and evaluate endemic biocontrol agents (field collection dissections and growth chamber and viral assay).
  3. Distribute biocontrol agents through land grant institutions and biocontrol authorities for control assessments on local beetles.
  4. Determine viral “cocktail” effectiveness across the region for implementation of worldwide distribution for control and preventive measures where CRB is a threat.

Expected Outputs, Outcomes and/or Impacts

Projected Participation

View Appendix E: Participation

Literature Cited


Land Grant Participating States/Institutions


Non Land Grant Participating States/Institutions

Palau Community College Cooperative Research & Extension
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