For more than a decade, the University of Â鶹´«Ã½ at ²Ñ¨¡²Ô´Ç²¹ has been on the front lines of the battle against the invasive coconut rhinoceros beetle (CRB). Now, researchers at the (CTAHR) are seeing progress in a promising weapon: viruses.
“Pathogens are being used, but viruses are being underutilized as far as I¡¯m concerned,” said Mike Melzer, researcher and virologist at CTAHR¡¯s Department of Plant & Environmental Protection Sciences. “I know we can find viruses that will have a really good impact on important target species that are pests in Â鶹´«Ã½.”
Unlike chemical pesticides, the virus infects CRBs from the inside, weakening and killing them before they reach adulthood. By targeting larvae, the virus can suppress beetle populations over time while minimizing harm to non-target species. Researchers believe the virus should also infect adults, making them lethargic and less likely to damage palms.
Rigorous safety standards
For 10 years, federal regulators told UH researchers that the CRB virus could not be brought into Â鶹´«Ã½ due to a lack of adequate containment facilities. A breakthrough finally came in early 2025 through a collaboration with the U.S. Department of Agriculture¡¯s permit unit.
Current permits specifically restrict research to the larval stage because larvae cannot fly, significantly reducing the risk of an accidental environmental release. “We rear CRB for research purposes and we’ve never lost an adult out of there,” he said.
Protecting the Kauaʻi stag beetle
A primary goal of the current lab testing is to ensure the virus is host-specific and will not harm Â鶹´«Ã½‘s native ecosystem. While the virus has been used effectively in other Pacific nations, Melzer emphasized that Hawai?i has unique native species to protect, such as the Kauaʻi stag beetle.
“Nobody really gives too much of a thought about CRB where the virus has been released” Melzer noted, explaining that while some damage remains, the virus keeps it at a manageable “two out of 10” rather than the devastating levels seen in Â鶹´«Ã½.
A good night¡¯s sleep
In August 2025, Melzer and a former student, Nelson Masang Jr., traveled to Palau, a region where the virus has successfully managed the beetle for decades, to collect genetic variants of the virus. The research trip was part of a close partnership with Professor Chris Kitalong and Jacques Idechong of Palau Community College.
The research, led by doctoral student Kristen Gaines, involves infecting CRB larvae to observe how the virus spreads. Early results have been encouraging, showing that the virus can kill larvae within 12 to 30 days. “I sleep a little better at night because Kristen said she¡¯s starting to see larvae getting lethargic and dying after just being exposed to the virus,” Melzer said.