Wailuā Golf Course to limit play, as state sprays trees for coconut rhinoceros beetle

The Wailuā Golf course on the Eastside of Kaua‘i will offer limited play from Oct. 9 to Oct. 13, so the course’s coconut trees can be sprayed for the invasive coconut rhinoceros beetle.

Hawai‘i Department of Agriculture and University of Hawai‘i researchers will conduct the drone-based treatment of the palm trees, in an effort to eliminate the course’s coconut rhinoceros beetle infestation. So far, 31 adult beetles have been found in traps at the golf course.

University researchers Dan Jenkins and Mohsen Paryavi have been developing the drone-based treatment on O‘ahu and will be piloting the drones on Kaua‘i. The goal is to treat about 20% of the approximately 580 coconut palm trees at the site with the pesticide, Cypermethrin (also known as the general use pesticide, Demon Max), which has been found to be effective in killing coconut rhinoceros beetles. Palm trees on the property range from 60 to 90 feet tall.

“With the extreme height of the palm trees, overhead pesticide treatment is the best way to reach the crowns of the palms where the CRB [coconut rhinoceros beetles] bore into the trees,” said Sharon Hurd, chairperson of the Hawai‘i Board of Agriculture. “The drones also provide a more targeted and efficient application of the pesticide rather than widespread spraying.”

In addition to the University of Hawai‘i researchers, the state Department of Agriculture will be flying in six staff from the Plant Quarantine and Plant Pest Control Branches on O‘ahu and Hawai‘i Island, and two staff from the Coconut Rhinoceros Beetle Response Team on O‘ahu.

The beetles were first detected in Hawai‘i in December 2013 on O‘ahu and were first detected on Kaua‘i, near Līhu‘e Airport, in late May 2023. Since then, 82 traps have been deployed around Kaua‘i. So far, a total of 34 beetles have been found in traps, at the golf course, near Līhu‘e Airport and at a green waste facility in Līhu‘e. In addition, three coconut rhinoceros beetle larvae were found in Kilauea and 23 larvae at Nukolii Beach Park. Multi-agency eradication efforts continue on the island.

Later today, the state Department of Agriculture’s Advisory Committee on Plants and Animals will meet to consider establishing a new interim rule restricting the interisland movement of palm plants; decomposing plant material, such as compost, wood or tree chips; mulch; potting soil; and other products containing plant material. In addition, the new interim rule restricts the interisland movement of palm plants higher than four feet in height to enable closer inspection of palm crowns where the beetles are most likely to bore into a tree. More information on the proposed rule is forthcoming.

Coconut rhinoceros beetles are a serious pest of 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 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 beetles, thereby killing the tree as well. Tree mortality after coconut rhinoceros 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, Nukunono, American and Western Samoa and Guam. It is still not known exactly how the beetles arrived in Hawai‘i.

The Wailuā Golf Course schedule next week is as follows:

• Oct. 9, front nine holes are available until 10 a.m., with only back nine holes available for the remainder of the day;
• Oct. 10, back nine available, with front nine closed for the day;
• Oct. 11 back nine available, with front nine closed for the day;
• Oct. 12, front nine available, with back nine closed for the day; and
• Oct. 13 front nine available, with back nine closed for the day.

For questions regarding golf tee times, contact the Kaua‘i Department of Parks and Recreation at 808-241-6666 or visit www.kauai.gov/parks.

Reports of possible CRB infestation may be addressed to the CRB Response Team at 808-679-5244 or email info@crbhawaii.org or the state’s toll-free Pest Hotline at 808-643-PEST (7378). For more information, please contact the Hawai‘i Department of Agriculture at 808-973-9560, email hdoa.info@hawaii.gov, or visit www.crbhawaii.org.