Photo of CRB and larvae

Hawaiʻi’s Fight to Save Its Palms and Heritage

The Coconut Rhinoceros Beetle (CRB) poses a significant threat to Hawaiʻi's agricultural sector and cultural landscape, having spread across O'ahu since its detection in 2013. With eradication no longer feasible, the community's focus has shifted to controlling the beetle's impact through natural methods. This article explores the beetle's devastating effects on palm trees and other crops, how to detect its presence, and the innovative community efforts to manage its spread, inviting readers to learn more about safeguarding our island's heritage and food security.

PSA: Coconut Rhinoceros Beetle

By Haley Kaukea Eiko McKinnon, co-owner of Ahiki Acres, ahikiacres.com
Photo of CRB and larvae
A beetle and the beetle larvae. Photo courtesy of Ahiki Acres

The Coconut Rhinoceros beetle (CRB) is one of the top threats to Hawaiʻi agriculture and our community. CRB were first found in Hawaiʻi in 2013 at the Joint Base Pearl Harbor-Hickam. Poor management has led to widespread infestations on Oʻahu. Unfortunately, CRB is past prevention/eradication on Oʻahu so the best we can do is keep populations low. We must come together in our communities to spread awareness and implement natural solutions to tackle this horrible threat to our local food system, economy, and cultural heritage.

Impact

CRB can kill palms and other trees if they burrow and eat below the bark. Can you imagine our islands without palm trees or coconuts? CRB prefer to feed on coconut, royal, date, and fan palms, but if these trees are unavailable, CRB will feed on banana, kalo, pineapple, and sugarcane. Our food system and local heritage is in danger!

Detection

How do you know if you have CRB present? CRBs create noticeable boreholes in crowns of palm trees. As palm fronds emerge, V-shaped cuts or holes along the central spine or center vein are signs of feeding. Also, infested trees often show a general decline in health.

Photos of CRB bore holes
Photo of V-shaped cuts

CRBs bore into the base of palm fronds; damage shows in the V-shape cuts along the edge of a mature frond. Photos courtesy of Coconut Rhinoceros Beetle Response, crbhawaii.org

Control

Green waste management! If you have mulch or compost piles, check them often. Spread out the piles and if you see larvae, squish them. They are large so I usually use a shovel. Our friends have had success feeding the larvae to their dogs but we haven’t tried that yet. 😅 We have been using netting on our compost piles at the farm and it has proven effective (see pictures below). When the CRB fly into or out of the piles, they get stuck in the netting and die. We are following multiple organizations who are researching more methods of mulch management including steaming and the incorporation of Korean Natural Farming pig pens (I’m ready for some Kune Kune pigs on the farm!).

Photo of netted compost pile
Netted compost pile.
Photo of CRB caught in netting
CRB caught in netting.

Food for thought: There are non-organic pesticides that have shown some efficacy in killing CRB by injecting palm trees or drenching the soil but these pesticides are toxic and not well-regulated. For example, the next time you buy a coconut, ask yourself, where did that coconut come from? Did it come from a tree injected with a restricted use pesticide? If it did, that coconut you are eating/drinking is toxic. It’s difficult to trace back where your coconut came from (many vendors aggregate from tree climbers all over the island). The best we can do is spread awareness of the dangers of injecting poison into fruit-bearing trees and hope no one is ever poisoned.

CRB found in banana trunk at a farm in Waialua. Photo courtesy of Ahiki Acres.

If you want to learn more on CRB, I’d recommend visiting our neighbor Yogarden on their volunteer days: every Thursday, 9am-12pm and 4pm-6pm at 41-1009 Kakaina St, Waimanalo, HI 96795. They are working diligently with other local organizations on natural solutions!