The invasive insect has decimated the Pacific’s coconut palm populations. Now it’s been found on Kauai.

Coconut rhinoceros beetles have been discovered on Kauai, marking the insect’s first confirmed detection outside Oahu since its arrival in Hawaii almost 10 years ago.

Two beetles were found on Kauai near Lihue Airport, one found alive at a green waste transfer station on May 31 and another found two days later, dead in a trap close by.

The Department of Agriculture’s detection on Kauai comes after years of warnings from invasive species experts and entomologists, who have warned that Hawaii’s landscape would be overturned if the horned beetle gained a foothold.

Coconut Rhinoceros Beetle larvae multiply in sites such as green waste transfer stations, like Kauai’s, which have perfect breeding conditions. (David Croxford/Civil Beat/2023)

That’s because the beetles bore into the hearts of palm trees, effectively killing them in place.

The beetle is now firmly established on Oahu and, earlier this year, specialists announced they had moved into damage control and would no longer be able to eradicate the insect from the island.

Part of that plan was making sure it doesn’t hitch a ride anywhere else.

Green waste is a key means of transport for the beetle, which breeds in mulch and foliage, making its appearance on Kauai more puzzling.

That’s because a lot of mulch is produced on Kauai already, according to Mike Melzer of the University of Hawaii Coconut Rhinoceros Beetle Response team.

Finding the answer to where the insect came from will hopefully come soon, as tissue samples from the bugs have been sent from Kauai to UH Manoa for testing.

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“I’m hoping these are just two one-offs that came over in a cargo plane,” Melzer said in an interview.

Meanwhile, additional traps have been set and extra surveying is being undertaken to see if there are more in the area surrounding where the two beetles were found.

Squad members from UH’s CRB response team are traveling to Kauai to help DOA staff assess the situation too.

Fumigation of the green waste transfer station is also being organized, with equipment being sent to Kauai from Oahu to sterilize the areas where the beetles were discovered, which is expected to happen early next week.

The coconut rhinoceros beetle has been able to cut palm populations in half on other Pacific islands.
(David Croxford/Civil Beat/2023)

DOA Chair Sharon Hurd said previous efforts to control the horned beetle were underfunded and too little was known about them, leading to their unmitigated spread.

Now, after the legislature pumped about $2 million into the coming year’s state budget to address the beetle problem, Hawaii could be in a better place to eradicate whatever population exists on Kauai.

“We want to make sure this does not happen on Kauai,” Hurd said in a press release.

But it is still too early to make any real determination of the level of presence, according to Darcy Oishi of the DOA Plant Pest Control Branch.

Even so, the comparatively low amount of sea and air traffic to Kauai, along with several other factors, made its appearance on the Garden Island surprising, Oishi says.

“It’s going to be a tough couple of weeks or months,” Oishi said in an interview. “But it’s a lot better than where we were in 2013 on Oahu.”

“Hawaii Grown” is funded in part by grants from Ulupono Fund at the Hawaii Community Foundation and the Frost Family Foundation.

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