Guam moves to contain invasive rhino beetle, protect the region

INFESTED: A coconut tree in Barrigada can be seen Sept. 22 with damage caused by the invasive rhino beetle. David Sholing/The Guam Daily Post

Guam is no longer trying to eradicate the invasive rhinoceros beetle population on island. Instead, efforts have shifted to keeping the rhino beetle from spreading throughout the Micronesia region.

And with the recent award of $167,815 from the U.S. Department of the Interior, part of that focus will be on rhino beetles around the island’s ports of entry.

Glenn Dulla, research affiliate at the University of Guam and coordinator for the Biosecurity Division at the Guam Department of Agriculture, said the investment was provided through the bipartisan infrastructure law.

The funding will be used for the university’s Coconut Rhinoceros Beetle Pesticide Tree Injection Program, and will service ports of entry to prevent the beetle from spreading on Guam and throughout the region.

“Guam is a primary transportation hub for the rest of the islands in Micronesia. A great deal of the cargo that enters Micronesia transfers through Guam before it gets redistributed to smaller planes or boats to the other islands. Because of that, we are considered a high-risk threat to the rest of the islands because we have so many invasive species on Guam that aren’t on other islands,” Dulla said.

Guam is no longer in the eradication effort, Dulla said, instead officials are trying to manage the invasive species.

"The projects that we guide, at least for the Biosecurity Division, our jurisdiction is the ports of entry for invasive species management. Since the coconut trees became infested with rhino beetle, … at least 25% of the coconut trees on Guam have some sort of damage,” he said.

While managing all the coconut trees is not feasible due to cost, efforts have shifted to keeping the rhino beetle contained on island.

“So, we will be focusing on, at least for this project, protecting the region. Focused management around the airport, around the seaports, just to reduce the populations of rhino beetle around the loading area so they don’t escape to the other Pacific islands,” he said.

Other Micronesian islands may not have the funds or expertise to handle the invasive rhino beetle, Dulla noted.

“Really, a lot of the smaller islands, outer islands, don’t have the same resources as Guam. If they were to get the rhino beetle, they would be worse off than Guam,” he said.

To manage the rhino beetles around the ports of entry, the Department of Agriculture will utilize a pesticide method already used to combat termites.

“There are pesticides that can be injected in different types of trees to control the infected, … In Hawaii we are following their protocol, Hawaii Department of Agriculture,” he said. "What they found in Hawaii is they did 90% coverage of the trees in the area, they get significant populations of rhino beetle adults and have tree recovery. If you go below that … you get no measurable effect. So we are going to try to do 90% of the trees in a specific area and see if we can reproduce what’s been seen in Hawaii. If it works, then we move on to the rest of the trees."

Any time a pesticide is used around people, there is a natural concern about health and environmental impacts. It's a concern that the Agriculture Department and the university understand.

“But we are going to safeguard. … We are not going to put it in any fruit-bearing trees, coconuts are the primary target, but around the airport there are no fruit-bearing coconut trees. It's a hazard, … any tree that we inject, the protocol … is to remove any flowers or coconuts that are on these trees.” Dulla said.

Safeguards including removing fruits and flowers and posting signage around treated tress will be used to warn residents of the pesticide.

The government agencies will use Imidacloprid and Acephate chemicals to inject into infected coconut trees. The pesticide tree injections would be administered twice a year, or every six months.

Before management begins, Agriculture and UOG need to work with the Guam Airport and the Port Authority of Guam to determine which areas will be targeted and what management strategy will be deployed.

The Department of Agriculture is working with the airport to remove all the dead coconut trees around the facility, as they were deemed falling hazards and breeding sites for rhino beetles.

Dulla met Friday with airport officials to discuss the next phase in that project — tree planting.

“In collaboration of Guam Forestry, … we will try to plant other native trees in the airport area,” he said.

The goal is to complete the reforestation efforts by the end of the year.


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