City arborists protect Kakaako palms from invasive beetles
City arborists are continuing their battle against invasive coconut rhinoceros beetles by creating a barrier of treated palms in urban Honolulu.
The Honolulu Department of Parks and Recreation said crews on Monday started injecting a preventative treatment into about 800 palms at city parks, including Ala Moana Regional Park, Kewalo Basin Park, and Kakaako parks.
“We estimate that about a half of our palm tree inventory, of nearly 8,000 palms across the island, is concentrated from Moanalua to the Ka Iwi Coast,” Roxanne Adams, the city’s lead arborist, said in a news release. “So the goal is to create a barrier making it more difficult for the beetle to infiltrate into these dense groves.”
Previously city arborists treated palms around Diamond Head and at Hanauma Bay Nature Preserve. They are collaborating with the Hawaii Department of Agriculture on the large-scale treatment of palms around the island.
The palms are injected with the Xytect insecticide, which is designed to protect trees from a coconut rhinoceros beetle infection.
Other measures that have been taken in the past year and a half include the installation of protective netting on newly planted palms at Tracks Beach Park in leeward Oahu, and the removal of some 200 compromised palms along the leeward, northern, and windward coasts.
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Coconut rhinoceros beetles, or Oryctes rhinoceros, are native to Southeast Asia, and bore into their crowns and feed on their sap, damaging and potentially killing them. The invasive beetle was first detected in coconut tree trimmings at Joint Base Pearl Harbor-Hickam on Oahu in December 2013, and all of Oahu is now considered infested, according to the CRB Response Team.
“While we want to save as many palms as possible around the island, the spread of CRB is easier to mitigate in the urban jungle where there is more development and less rugged natural landscape, agriculture, and breeding site debris such as mulch piles,” Adams said.
Palms treated with an insecticide injection such as Xytect should be removed of their flowers to protect pollinators, and the fruit should not be consumed for a year, according to CRB Response. The treated trees are tagged.
Adult coconut rhinoceros beetles are black, about 2 inches long, with a visible horn, while the larvae live and feed in decomposing plant material, such as green waste and mulch. Signs of CRB damage in palms include V-shaped cuts, scalloped edges, and bore holes.
Sightings of invasive species should be reported to 808-643-PEST (7378) or 643pest.org.
