Eradicating Invasive Coconut Rhinoceros Beetle Means Protecting Economy, Ecosystem and Hawaiian Culture
By Nathan Christophel
May 19, 2024
Imagine a Hawai‘i where palm trees no longer sway. Crownless rotting trunks barely anchored in the earth stand lifeless in their place or grounded and in various stages of decay.
Dead coconut trees on Guam after a coconut rhinoceros beetle infestation. (Screenshot of an image on the Coconut Rhinoceros Beetle Response organization website)
Bananas, hala, taro, papaya and the endangered native Hawaiian palm loulu would vanish next, casualties of the same lost war against a six-legged scourge. The invasive and highly destructive coconut rhinoceros beetle.
It’s the extreme of a bleak and tragic future timeline in the islands; one fraught with economic hardship, ecosystem devastation and irreparable damage to Native Hawaiian culture and heritage.
Officials and organizations throughout the state don’t want that to happen and are working to eradicate and contain the invasive beetle that invaded the islands more than 10 years ago, starting on O‘ahu. The insect was first discovered on the Big Island last fall.
The Hawai‘i County Council joined the battle against the coconut rhinoceros beetle last week during a meeting of its Finance Committee by supporting the implementation of a Hawai‘i County Department of Environmental Management initiative aimed at minimizing the beetle’s breeding grounds on the Big Island.
Resolution 516, introduced by Puna Councilman Matt Kāneali‘i-Kleinfelder by request, authorizes the department’s receipt of a $200,000 Hawai‘i Department of Agriculture grant to pay for the project. The council voted 9-0 to forward the resolution with a favorable recommendation to its next regular session for adoption.
Companion measure Bill 162, also introduced by Kāneali‘i-Kleinfelder by request, appropriates the grant funds. The council members’ 9-0 vote will move that measure ahead with a favorable recommendation.
The beetles often expand their territory by stowing away in green waste, mulch and compost while they are being transported. The scarabs, native to Southeastern Asia, typically use these types of decaying plant materials for breeding, as well as decomposing stumps, rotting coconut logs and felled trees.
An adult coconut rhinoceros beetle. (Screenshot of an image on the Coconut Rhinoceros Beetle Response organization website)
Coconut rhinoceros beetle larvae. (Screenshot of an image on the Coconut Rhinoceros Beetle Response organization website)
On average, one female can lay more than 90 eggs throughout its adult life.
Larvae are sluggish, white and crawl on their sides. They can grow to between 2 and 4 or more inches long. The C-shaped grubs live and feed on the decaying plant matter of the breeding site where they hatched.
It takes about 4 to 6 months for larvae to mature into adults.
Adult beetles are about 2 inches long and solid black. They can fly and are active in the evening and at night. Both sexes have a horn on their head; however, a male’s horn is more than twice as long as a female’s. Their lifespans are between 4 and 9 months.
That means it is possible, albeit a short window, that three generations of coconut rhinoceros beetles could be reproducing at the same time.
Since it only takes a matter of hours or less for green waste, compost and mulch to be moved from one area on the Big Island to another, all three generations could be increasing the insect’s population distribution here at the same time, too.
Responsible management and tighter control of the decomposing plant materials the invasive pest uses for breeding are crucial to winning the war for eradication before Hawai‘i County becomes like O‘ahu, where the beetle was first detected in December 2013 near the Daniel K. Inouye International Airport at Mamala Bay.
The battle there transitioned from wiping out the coconut rhinoceros beetle to containing the widespread infestation so the insects can’t get to the other islands.
“With the county providing green waste and mulch services, controlling the [coconut rhinoceros beetle] population in Hawai‘i is crucial for the preservation of biodiversity, mitigation of economic losses, ecological impacts and impacts to cultural resources,” said the Environmental Management Department’s request for council action.
The department will use the $200,000 in state grant funds for campaigns to raise public awareness about the invasive bug and its devastating impacts and help prevent the beetle’s spread by:
Implementing monitoring programs that identify the threat.
Detection and prevention of the beetles.
Promoting best practices and management of green waste, palms and other “host materials” used by the invasive bug for breeding.
Encouraging community participation and reporting.
The department said outreach and education are key to controlling coconut rhinoceros beetle populations and protecting coconut palms and other plant species they attack.
“I don’t think people really know the effects of this beetle because it’s not only the coconut palms, the regular palms, it’s the papaya …,” Craig Kawaguchi, coordinator at the Environmental Management Department, told the council on May 14 during the Finance Committee meeting.
“It’s everything,” finished Kona Councilwoman Rebecca Villegas. “I have hopes that at some point we’ll stop importing these species accidentally to the demise of our agricultural industry and all of our native crops. But I think the word is spreading more prolifically and the understanding of the urgency.”
Coconut palms with damage caused by coconut rhinoceros beetles. (Screenshot of an image on the Coconut Rhinoceros Beetle Response organization website)
Adult beetles, as their name suggests, prefer coconut palms along with royal, date and fan palms. They feed on the growing spear of palm trees using their horns and spiny legs to dig into the crown, causing significant and potentially fatal damage. That damage also can leave the tree susceptible to disease.
The invasive insects, however, are not picky.
If their primary food sources are not available, the beetles will feed on other palms and tropical crops, including bananas, sugarcane, pineapple, taro, hala, papaya and the endangered native Hawaiian palm loulu.
All of those tropical plants are important to the state’s agricultural industry, but those such as taro, hala and the loulu also have significant importance in the Native Hawaiian culture.
The invasive scarab was first discovered on the Big Island in early October 2023. A resident of Waikōloa found six coconut rhinoceros beetle larvae in a decaying palm tree stump on their property.
Three adult beetles, the first to be found in Hawai‘i County, were captured in April.
One male was caught by a trap at the Hawaiian Earth Recycling facility near the West Hawai’i Sanitary Landfill in Pu’uanahulu southwest of Waikōloa. The other two, a male and a female, were captured in a trap hosted by the Waikōloa Dry Forest Initiative.
“Unfortunately, detections of live adult beetles are an indication that [coconut rhinoceros beetles] are breeding in the Waikōloa area,” said Hawai‘i Board of Agriculture Chairwoman Sharon Hurd at the time.
Surveillance for coconut rhinoceros beetle has been ongoing on all islands, including traps at airports, harbors and other strategic locations.
Coconut rhinoceros beetles found in April at the Waikōloa Dry Forest Reserve. (File photo courtesy of the Big Island Invasive Species Committee)
Larvae of coconut rhinoseros beetle discovered in October 2023 in Waikōloa. (File photo courtesy of the Big Island Invasive Species Committee)
Since the beetle’s first detection on the Big Island, the Big Island Invasive Species Committee has worked with partners from the U.S. Department of Agriculture, state Department of Agriculture and University of Hawai‘i to deploy an extensive trap network near the original site and in high-risk areas around the island.
Nearly 150 traps have been installed and more deployments are ongoing.
The state Agriculture Department Plant Pest Control Branch and the Coconut Rhinoceros Beetle Response organization also did extensive surveying and treatment activities earlier this month.
Plans are in the works to try new methods of treatment for palm trees, and a new generation of smart traps will be included in future trap deployments.
Inspectors with the state ag department’s Plant Quarantine Branch also have been on heightened alert for mulch or compost arriving on the Big Island. Any from O‘ahu going to neighbor islands are required to be heat treated or fumigated before shipping to kill any invasive beetles hiding inside.
At the county’s green waste and mulching facility in West Hawai‘i, those materials are placed in windrows and sit for 15 days, being turned over at least five times and maintained at a temperature of 131 degrees to kill any of the beetles and other pathogens and insects such as ants.
There also are five traps located around the facility to detect any coconut rhinoceros beetles.
The site remains beetle-free.
The Environmental Management Department anticipates more green waste coming to the West Hawai‘i site with the new outreach program, which will encourage more people to drop off their green waste so the county can have more control over the invasive beetle’s spread.
So some of the state grant funds will cover the cost of additional trips to transport materials from there to the county’s East Hawai‘i facility to make additional room available for the expected increased volume of green waste.
The county will also purchase a dog trained to sniff out coconut rhinoceros beetles and additional traps as part of the public awareness project.
“I kind of feel like this is one of those scenarios where when I see a big Kona cruiser cockroach at my house, cruising around, I know that I’m in trouble because I might see that one, but it’s an indication that there are a lot in places I can’t see, and that is the highlighted concern and crisis, and I’ve heard it,” Villegas said, adding that to lose indigenous plants and coconut trees would be devastating in many ways for the island. “So thank you for doing everything in your power to ensure that the coconut rhinoceros beetle, any potential spread through our mulching facilities stops.”
Screenshot of an image on the Coconut Rhinoceros Beetle Response organization website
The state Agriculture Department is distributing the $200,000 grants to each of the state’s counties to help control the spread of the coconut rhinoceros beetle by minimizing breeding sites.
The Hawai‘i Legislature this year approved $20 million for the state Agriculture Department to use for invasive species control. The department’s No. 1 priority is Hawai‘i’s biosecurity.
“We’re in a state of crisis for biosecurity,” state Sen. Mike Gabbard, chairman of the Hawai’i Senate’s Committee on Agriculture and Environment, told Hawai‘i Public Radio in April. “Invasive species threaten the livelihoods of our farmers and everyone they serve. So, if we don’t prioritize biosecurity now, we could soon see the collapse of our natural and food ecosystems across the state.”
The state ag department is also now accepting proposals for projects by community organizations on the Big Island, Maui, Kaua‘i, Moloka‘i and O‘ahu in support of eliminating the coconut rhinoceros beetle in green waste.
Green waste includes grass clippings, leaves, branches, hedge and tree trimmings, fruits and vegetables, palm fronds and other similar plant materials that can be composted.
A total of $200,000 is available. A maximum of $40,000 will go to one project on each of the islands. Priority will be given to community groups that have demonstrated concern about the coconut rhinoceros beetle during public meetings or activities throughout the past year.
Proposals must be submitted electronically by noon June 7 to jonathan.k.ho@hawaii.gov. They will be reviewed for clear objectives, measurable outcomes and data collection methods.
Details and application information can be found online.
Just within the past year, coconut rhinoceros beetles spread to Kaua‘i, Maui and the Big Island.
A recent story by Hawai‘i News Now says “scores of palm trees” on O‘ahu are already dying because of the island’s coconut rhinoceros beetle infestation, making what was just a fear become reality.
The scalloped leafe edges on this fan palm were caused by the coconut rhinoceros beetle. (Screenshot of an image on the Coconut Rhinoceros Beetle Response organization website)
Bore holes caused by coconut rhinoceros beetles. (Screenshot of an image on the Coconut Rhinoceros Beetle Response organization website).
The Pacific Island Times said in a March 2021 story that coconut rhinoceros beetle infestation throughout the Pacific islands is estimated to cost the region $169 million a year by 2040 if their invasion is not stopped.
May is Hawai‘i Invasive Species Awareness Month. This year’s theme is “Who protects Hawai‘i from invasive species? You do.”
Everyone is encouraged to take action to help prevent and manage invasive species. Even the most simple help, such as not planting invasive plants in your garden, reporting new pests and volunteering with local organizations.
The Hawai‘i Invasive Species Council and Coconut Rhinoceros Beetle Response organization recommend several measures to help control the spread of the coconut rhinoceros beetle and minimize their breeding sites, including regularly using green waste bins and grinding plant waste.
If you find a beetle, adults or larvae, capture and put it in a hard plastic or glass jar. The O‘ahu Invasive Species Committee recommends if you do not have a container, crush the insect.
Record where you found it and call the Coconut Rhinoceros Beetle Response organization immediately at 808-679-5244 or email info@crbhawaii.org.
“Unfortunately, it’s only getting worse,” said Honolulu City Councilman Tyler Dos Santos-Tam before a community meeting on May 14 about O‘ahu’s infestation. “If we’re going to change course, we have to be more diligent about this issue. That starts with spreading more awareness. Our communities need to know why these pests are a problem and how we can stop them.”