New interim rule aims to curb spread of coconut rhinoceros beetles

The Hawai‘i Department of Agriculture has established a new interim rule to help stop the movement of the coconut rhinoceros beetle from designated beetle-infested areas to non-infested areas in the state.

Beetle grubs were found in Kīhei in November 2023, but have not been detected on Maui since.

On Friday, the Advisory Committee on Plants and Animals recommended approval of a new interim rule that restricts the movement of palm plants; decomposing plant material, such as compost, wood or tree chips; mulch; potting soil; and other landscaping products that may harbor beetles, from infested areas to non-infested areas.

In addition, the interim rule restricts the movement of palm plants higher than 4 feet tall, which will enable closer inspection of palm crowns where beetles are most likely to bore into a tree. The interim rule designates the island of O‘ahu as a beetle-infested area and is subsequent to other interim rules that were issued in June 2022 and October 2023. 

The interim rule was signed Friday by Hawai‘i Department of Agriculture Chairperson Sharon Hurd and is effective immediately. It is valid for one year, while the department finalizes a permanent rule, which is slated to be considered by the Hawai‘i Board of Agriculture later this month.

Any individual, company, or organization that violates the rule will be charged with a misdemeanor and fined not less than $100 and up to $10,000. Penalties for a second offense committed within five years will require the violator to pay for the cost of clean-up and decontamination fees to remove contaminated materials, as well as the cost to fully eradicate any coconut rhinoceros beetle infestations caused by the violation. Repeat violators will be fined not less than $500 and up to $25,000. 

The department’s Plant Quarantine Branch inspectors at all island ports are concentrating efforts on inspections of potential coconut rhinoceros beetle host material transported between islands.

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. An adult beetle is about two inches long, all black and has a single horn on its head. Beetle grubs live in decomposing plant and animal waste. Adult beetles prefer to feed on coconut and other larger palms and are a major threat to the health of these plants.

Residents may go to the Coconut Rhinoceros Beetle Response website at:  https://www.crbhawaii.org/ to learn more about how to detect the signs of beetle damage and how to identify beetle life stages. Reports of possible beetle infestation may also be made tothe state’s toll-free Pest Hotline at 808-643-PEST (7378).

Surveillance for coconut rhinoceros beetles has been ongoing on all Neighbor Islands, including pheromone traps at airports, harbors and other strategic locations. The traps are used for early detection of beetle infestations and are being monitored by Agriculture Department, island Invasive Species Committees and the University of Hawai‘i.

The coconut rhinoceros beetle is a large scarab beetle that was first detected on O‘ahu in 2013. The beetle has since been detected in many neighborhoods on O‘ahu, In May 2023, CRB was detected on Kaua‘i and collaborative eradication efforts continue on the island. On Hawai‘i Island, the beetle was detected in a palm tree stump Waikoloa in October 2023 and a single beetle was found dead in a trap last month in that same area.

The beetle is a serious pest of palm trees, primarily coconut palms, as the adult beetles bore into the crowns of the palms to feed on the trees’ sap. New unopened fronds are damaged in this way and when fully opened, may break and fall unexpectedly. If the beetles kill or damage the growing point of the palm, the tree may die. Secondary fungal or bacterial pathogens may also attack the wounds caused by the beetle, thereby killing the tree as well. Tree mortality after a beetle attack has been reported to be anywhere from 10% to 50%. Dead trees then become a safety hazard as they may fall unexpectedly after the trunk rots, potentially resulting in bodily injury or property damage. 

The coconut rhinoceros beetle is a major pest of palms in India, the Philippines, Palau, Fiji, Wallis and Futuna, Nukunono, American and Western Samoa and Guam. It is still not known exactly how the beetles arrived in Hawai‘i.