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When Typhoon Dolphin passed north of Guam in May 2015, it brought winds over 100 mph, destroying nearly 400 homes and damaging many others. The storm tore branches from trees, knocked down power lines, and flattening crops, including 7,000 banana trees. Debris covered the island.
In the aftermath, trucks hauled away fallen limbs and brush. Normally, little thought is given to storm debris once it's cleared. But in Guam, eight years earlier, the coconut rhinoceros beetle (CRB) had been detected.
From egg to adult, CRB larvae develop in decomposing coconut logs and decaying plant material--a process that takes 4 to 6 months. Managing green waste by chipping, turning, heating, or burying disrupts this lifecycle and is crucial to controlling CRB populations. However, Typhoon Dolphin created thousands of tons of debris; it wasn't feasible to manage all of it for CRB and much of the debris lie on forested regions. For CRB, it was akin to a kid in a candy store; they had an island covered in green waste.
About six months after the typhoon, CRB populations began to surge, eventually exploding across the island, hitting Guam's palms hard. Eventually, as debris broke down and beetles had less habitat, the outbreak subsided and CRB population levels began to decrease, but it took years.
Jovic Caasi, a researcher at the University of Guam, developed a computer model to simulate CRB populations based on their biology and environmental factors like food availability and green waste. Using data from before and after Typhoon Dolphin, he calibrated the model to help predict CRB outbreaks and evaluate control strategies. He wrote about the model in a paper published last year.
Both the model and real-world experience show that the most effective way to control large CRB populations is to disrupt their lifecycle through green waste management. Caasi's model estimates that doubling the removal of green waste could eliminate CRB from Guam. But like Hawaii, Guam has forests and wild areas where fallen debris isn't easily managed. The risk remains, especially with the looming threat of future storms.
"If typhoons become more frequent due to climate change, this could mean a long-term increase in green waste and more breeding sites," Caasi and his co-authors write, leading to further damage to coconut palms and other host plants.
The CRB situation on Oahu is already severe, but not so on the neighboring islands. On Maui, the only known live CRB detection was in November 2023 in Kihei. The Hawaii Department of Agriculture destroyed all infested material and treated nearby trees, and staff from the Maui Invasive Species Committee (MISC) surveyed over 26,000 palms. Community reports of suspected larvae, beetles, and palm damage continue to come in daily, but none so far have yielded a positive detection.
Green waste management is a powerful prevention tool. Removing dead palms eliminates potential CRB habitat and also provides an opportunity to inspect host material for larvae. In fact, larvae found in the crown of a dead palm in Kihei were only discovered because tree trimmers cut it down.
Early detection and rapid response are essential to preventing CRB from establishing itself on neighboring islands and causing outbreaks, especially after storms or hurricanes. If you have palms on your property, check them regularly for damage and ask your arborist if they are aware of CRB feeding damage, identification, and reporting. Always manage green waste responsibly. Either haul it to an approved composting facility, where it will be inspected, or keep it on-site and monitor it regularly. Green waste piles should be chipped, composted, and turned frequently to check for pests like CRB. Illegal dumping of green waste creates unmonitored habitats, increasing the risk of CRB spread. Be pono in how you manage your green waste.
Find hours and locations of Maui County waste facilities here: https://www.mauicounty.gov/765/Landfill-Information Learn more about CRB identification and prevention at CRBresponse.org, and report any suspected CRB on Maui at 643-PEST.org or by calling 643-PEST (7378).
n Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia'i Moku, "Guarding the Island," is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island's environment, economy, and quality of life.