Crews are searching for coconut rhinoceros beetle breeding sites in the Kona area, where about two dozen of the invasive beetles have been found since first being discovered there in March.
Hawaiʻi Island was free of CRB until a handful were found in the Waikōloa area last year. Then in March, several more were found a few miles south around Kona, particularly around the Elison Onizuka Kona International Airport and the Hawaiʻi Ocean Science and Technology Park.
This month, three adults were found at the Hawaiʻi Community College's Pālamanui campus, and a lone adult was discovered a few miles north at Kīholo Bay.
Local officials say that as of Tuesday, about 24 beetles have been found in or near Kona. Most of the CRB that have been found are adults, so crews are looking for breeding sites to stop the beetle from spreading beyond the area.
“We think that this is all from one initial clutch, and in that case, these are all brothers and sisters that we're finding, but they all came out of one area that's maybe a couple feet across at most. So we're trying to find where that is,” Franny Brewer, program manager for the Big Island Invasive Species Committee, said.
Brewer was in Kīholo Bay on Tuesday, helping with the search for more evidence of CRB in the area.
She said that if there is a breeding site somewhere, it's not unexpected that the beetle has spread the way it has.
The concern now is that those CRB are mating, which would give crews about four or five months before the next generation of beetles emerges.
“Now we’ve really gotta be on it with our breeding material — our compost, our mulch, our green waste — what is out there where they could be laying eggs. And we have four to five months before the next generation starts to emerge, where we have a chance to get in there and find those babies and get rid of them before,” Brewer said.
CRB were first discovered in Hawaiʻi in 2013 but were kept from spreading beyond Oʻahu until 2023, when they were found on Maui, Hawaiʻi Island and Kauaʻi.
The beetle bores into, feeds on and can kill palm trees, which has forced the City and County of Honolulu to cut down some palm trees on Oʻahu, where CRB is considered widespread.
Other agencies, including the state Department of Agriculture, and the public are also responding to the situation.
“The department’s (Plant Pest Control Branch) has been treating, along with a bunch of landowners, as many trees as we can get our hands on. If there are any beetles that are emerging from mulch piles that we're not aware of, they will succumb to the pesticide treatments,” said Jonathan Ho, manager of the DOA's Plant Quarantine Branch.
The agriculture department is working with the County of Hawaiʻi to urge businesses and the public to stop the movement of potential CRB breeding material, such as mulch and other decaying plant material. That request could come in the next week or so, and would focus on anyone delivering breeding material.
The state made a similar voluntary request in December in response to the spread of avian flu.
At the same time, the DOA is working on an interim rule as part of a longer term answer to the spread of CRB.
In a Board of Agriculture meeting on Tuesday, Ho also said three CRB larvae were found in two shipping containers on Lānaʻi. The containers were full of plants, which were checked by inspectors and then buried in a trench to kill any missed beetles or larvae.
