Biocontrol and Oryctes Nudivirus updates

Biocontrol is the use of other organisms to control a pest. This is often the introduction of predators, parasites, or pathogens. Predators that feed on CRB here in Hawaii include pigs, chickens, mongoose and other bigger birds such as egrets. While these animals will eat larvae that are handed to them or on the surface of a breeding site, they usually won't search for food deep into a pile of breeding material and are not effective enough to significantly impact CRB populations across Hawaii. 

Another biocontrol is Fungi in the Metarhizium genus, which can control CRB larvae in breeding sites. However, it requires reapplication to breeding sites multiple times per year to be the most effective, alongside other limitations. It’s currently not approved for use as a biopesticide in Hawaii. 

The most effective biocontrol for CRB that has been utilized in other infested areas in the world is the virus Oryctes Nudivirus (OrNV). It is a virus that infects CRB, spreads naturally once introduced, and has suppressed populations in other countries to manageable levels. With approvals and permits to begin this research in 2025, it is now actively being explored at the University of Hawaii at  Manoa. A strain of the virus was imported from Palau in August last year and is currently being tested for effectiveness on the CRB we have here in Hawaii. Right now, the permit only allows for testing on larvae to ensure extra protections are in place to prevent accidental escape of adult beetles (which has never happened in the lab, but extra safety can be appreciated!) 

So far, research has been showing promising results with larvae dying within 12 to 30 days after contracting it. 

One main concern with biocontrols is often the off-target effects that introduced organisms can have on the environment. Luckily, biocontrol research has improved immensely and this nudivirus experimentation will include testing it on other non-targeted species such as native or beneficial beetles that are present in Hawaii.  

With the current trajectory of the research portion, the biocontrol may be ready for release in as early as 2 years. Following this research portion, there will be a process of state and federal regulations to approve any release.