Coconut rhinoceros beetle grubs have been found at a residence in Waikoloa Village on Hawaii Island, the state Department of Agriculture announced Friday.
It is the first discovery of the invasive beetle on the Big Island.
On Oct. 11, the resident found five large grubs (larvae) in a decaying palm tree stump on the property and reported it to the Coconut Rhinoceros Beetle Response Project.
Staff from the state DOA responded to the site and collected the specimens, which were sent to a University of Hawaii laboratory in Honolulu, where a DNA-based test was used to identify the grubs as CRB.
On Wednesday, the resident reported finding one more grub on the property. No other grubs or adult CRB have been detected so far on Hawaii Island.
DOA crews on Hawaii Island and CRB response staff from Oahu surveyed the immediate area and did not find additional CRB damage. A multiagency team will continue to survey the area. Additional pheromone traps, used for early detection of infestations, are being deployed from Waikoloa Beach to Waimea, as well as other areas around the island, according to the DOA. DOA staff also are trying to trace the origin and the pathway of the grubs found in Waikoloa.
The beetles are a serious threat to palm trees, primarily coconut palms, as the adult beetles bore into the crowns of the palms to feed on the tree’s sap. New unopened fronds are damaged in this way, and when fully opened, may break and fall unexpectedly.
If CRB kill or damage the growing point of the palm, the tree may die.
Residents are encouraged to go to the CRB Response website at: https://www.crbhawaii.org/ to learn more about how to detect the signs of CRB damage, how to identify CRB life stages, and how to report any suspected signs of damage or beetles/grubs via the CRB reporting feature.
Reports of possible CRB infestation may also be addressed to the CRB Response team at (808) 679-5244, email info@crbhawaii.org or the state’s toll-free Pest Hotline at (808) 643-PEST (7378).
CRB grubs live in decomposing plant and animal waste and may have been inadvertently transported across Oahu and to neighbor islands in bags of compost or mulch.
Residents on all islands are asked to be vigilant when purchasing mulch, compost, and soil products, and to inspect bags for evidence of entry holes. Adult beetles are about 2 inches long, all black and have a single horn on their head.
The CRB is a large scarab beetle that was first detected on Oahu in 2013. The beetle has since been detected in many neighborhoods on Oahu, and was detected on Kauai in May 2023, where eradication efforts continue.