coconut rhinoceros beetle — Maui Invasive Species Committee (MISC)

Coconut palms are woven into the culture of the islands; a beetle threatens that connection

Posted on November 16, 2023 by Lissa Strohecker

*Baskets woven from coconut leaves. Photo from Maui Nui Botanical Garden*

Would-be weavers spilled out of the shade under an open-sided tent at the Arbor Day event at Maui Nui Botanical Garden. Holding coconut leaves, they patiently worked the material back and forth in intricate patterns. At times, chatter came from the tent; other times, it was silent, brows furrowed in concentration. The kumu, master weaver Pōhaku Kaho’ohanohano, moved among the weavers, getting some started while trimming up and tying off the finished creations of others. Novice weavers hugged the kumu, beaming as they walked away with a new hat, bag, bowl, toy, or ornament created from a diminishing pile of leaves.

Coconut weaving is a tradition that dates back thousands of years throughout Polynesia. Coconut palms were first brought to Hawai‘i with the Polynesians. The coconut plant is akin to a pre-contact department store; it can meet needs and wants. Food (coconut meat) and drink (coconut water), material for building shelters, making rope, and weaving mats, bowls, and storage containers all come from the coconut. It’s even used for games and in ceremonial practice; the nut is used in ‘awa ceremony.

But the future of coconuts in Hawai‘i is at risk from a pest accidentally introduced to Hawai‘i. The coconut rhinoceros beetle is spreading on O‘ahu and has begun to reach other islands.

*The adult coconut rhinoceros beetle is nearly two inches in length, but because it’s nocturnal, it’s rarely seen. Photo courtesy Coconut Rhinoceros Beetle Response*.

At two inches long, the CRB is a beefy beetle, but it isn’t going to fly interisland on its own. Knowing what you are moving and where it comes from is the first step in preventing the coconut rhinoceros beetle from reaching Maui. By being alert to signs of CRB damage, a vigilant community can help find the pest early and keep it from becoming established.

*Bore holes made as the beetle eats through the crown indicate the beetle’s presence. Photo courtesy Coconut Rhinoceros Beetle Response*.

There are prevention measures in place. In October of 2023, the Hawai‘i Department of Agriculture (HDOA) instituted a temporary, one-year rule prohibiting the movement of high-risk material from O‘ahu to the rest of the state to reduce the risk of spreading coconut rhinoceros beetle. As of October, the following items cannot be moved without a permit: palm plants; decomposing plant material, such as compost, wood, or tree chips; mulch; potting soil; and other landscaping products that may harbor CRB.

These safeguards reduce but do not entirely eliminate the risk of spreading CRB. Here are steps you can take to keep the beetle at bay.

For Maui County, soil, compost, and mulch are the greatest risk. Contractors and landscapers bringing in container loads are doing so by permit, but careful sourcing – checking with the vendor if material came from infested areas – can prevent contamination. Homeowners purchasing bagged landscaping products are advised to be alert as well.

Why? It turns out that bags aren’t much of a barrier to a beetle that can chew through coconut trees. Even if the compost, mulch, or soil wasn’t sourced from an infested area, if bagged soil sits in an infested area, an adult beetle lay eggs in it. The first detection of CRB on Maui was a dead adult found in bagged soil; this was also the suspected vector of CRB found recently on Hawai‘i Island.

CRB larvae are found in soil, compost, and muclh. Larvae crawl on their side and if you suspect you have found one in Maui County, take a video and submit a report to 643PEST.org. Photo courtesy of Coconut Rhinoceros Beetle Response.

Know where your soil and compost are coming from and check for boring holes in bags and larvae. Storing material in closed containers will prevent beetles from laying eggs in them.

The quarantine rule also prohibits shipping coconut plants from O‘ahu that are taller than 4 feet to allow thorough inspection, but the soil in these and all potted plants could be a vector. CRB eggs are only about the size of 1/3 of a tic tac.

As CRB populations on O‘ahu continue to grow, the risk of accidentally transporting the beetle interisland will increase. Visit crbhawaii.org to learn more about distinguishing the Coconut Rhinoceros Beetle from similar-looking species and to see photos of palm damage that can indicate an infestation. Contractors and landscapers can find best management practices to reduce the risk of introducing CRB on the MISC website.

Find details about the interim rule on HDOA’s website. Report suspicious larvae and palm damage through the 643PEST.org reporting system. We need everyone’s kōkua to help protect Maui Countyʻs coconuts, from the royal grove in Kapuāiwa on Molokai to the palms that shade the beaches of Hāna.

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.

This article was originally published in the Maui News on November 10, 2023, as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Detection of Coconut Rhinoceros Beetle on Maui Highlights Importance of Community Involvement in Pest Prevention

Posted on September 21, 2023 by Lissa Strohecker

*An abbreviated list of best management practices for Maui.*

The Coordinating Group on Alien Pest Species (CGAPS), program staff from the Hawaiʻi Invasive Species Council (HISC), and the five Invasive Species Committees (ISCs) in Hawaiʻi are urging vigilance by contractors and landowners to prevent the accidental spread of invasive species.

To support these efforts, CGAPS, HISC support staff, and the ISCs have compiled a list of best management practices (BMPs) for coconut rhinoceros beetle (CRB), little fire ants, and other species.

This appeal comes at a time when the urgent need to address impacts from the Maui fires may increase the introduction of infested materials from off-island, and CRB has been detected on both Maui and Kauaʻi.

The proposed reissuance of an emergency quarantine measure, Plant Quarantine Interim Rule 22-1, which restricts the movement of mulch and other potential CRB host materials from Oʻahu, is an important step, but by itself will not be adequate to the spread of this harmful pest. Contractors and individuals need to be sure that pests are not unwittingly moved in palm trees, green waste, mulch, loose or bagged compost, bagged soils, and similar items.

Throughout the state, the continued spread of pests poses significant risks:

Kauaʻi: The recent arrival of the coconut rhinoceros beetle pest to Kaua’i (detected May 31, 2023) highlights the threat posed by the movement of infested material. A decade of research on controlling the pest could lead to eradication on Kaua’i, but limiting the human-vectored spread is critical to achieving this goal.
O’ahu: Continued human-vectored spread will exacerbate the challenges in addressing this pest.
Maui County: with the increased volume of material moved to and around Maui to help with fire recovery efforts (including mulch and imported coconut coir, mulch, or greenwaste for use in erosion control sock filler), mulch and compost for restoring burn scars, and plants for restoration, there’s an increased risk of introducing invasive species.
Hawai’i Island: To date, CRB have not been detected on Hawai’i Island. Should they arrive, they would likely spread quickly, given the low population density and plentiful habitat that could lead to challenges in detecting and eradicating the pest.

The BMPs highlight practices to prevent the spread of coconut rhinoceros beetles, but also provide general guidelines for little fire ants, coqui frogs, two-lined spittle bug, and other invasive species.

For restoration projects, the BMPs provide guidance on fire risk assessments and non-invasive characteristics for selecting plants.

For more information:

List of Best Management Practices: https://dlnr.hawaii.gov/hisc/files/2023/09/BMPs-for-Invasive-Species-Prevention-091223.pdf
Christy Martin, Coordinating Group on Alien Pest Species, christym@rocketmail.com
Coconut Rhinoceros Beetle Response: (808) 679-5244, info@crbhawaii.org
Island-based Invasive Species Committees: https://www.hawaiiinvasivespecies.org/
Pacific Fire Exchange: Melissa Chimera, melissa@hawaiiwildfire.org

CRB spells trouble for Hawaii’s palms

Posted on July 28, 2014 by Lissa Strohecker

At over 2.5″ in length, the Coconut Rhinoceros Beetle would seem hard to miss, yet it spends most of it’s life in the crown of a palm tree. Photo courtesy of Hawaii Department of Agriculture.

At two and a half inches long and sporting large horns on the front of its head, the coconut rhinoceros beetle (CRB) is a remarkable-looking creature, but this lumbering giant of an insect is also a devastating pest of coconut and palm trees. Following its arrival on Palau in 1942, this critter from Southeast Asia quickly spread widely, wiping out 50 percent of the palms in the archipelago.

On December 23, 2013, during a routine survey of the Joint Base Pearl Harbor-Hickam, surveyors discovered the coconut rhinoceros beetle in palms on the base, marking it the first reported case of the insect in Hawai‘i.

Teams mobilized to survey the surrounding area and control the infestation. Based on the size of the population, the beetle may have been present for up to two years.

Populations of the beetle in its home range are kept in check by natural controls (predators, disease, and competition) but globalized shipping has transported the beetle throughout the Pacific; it has become a major palm pest, affecting the Philippines, the Republic of Palau, Fiji, American and Western Samoa, and most recently Guam. It has spread elsewhere in the world, hitching rides in the holds of aircraft, through nursery stock, cargo, mulch and sawdust.

The beetles leave boring holes in the crown of coconut palms. Photo courtesy of HDOA

When coconut rhinoceros beetle was detected in Guam in 2007, Hawai‘i officials grew concerned that the pest would make its way here, given the regular exchange of goods between the islands; however, it’s not known how the beetle arrived in Hawai‘i, nor where it came from.

Notable as they are in appearance, these beetles spend most of their adult stage out of sight, high in the tops of coconut trees. These monstrous beetles bore into the crowns of healthy palms, biting through unopened leaves and then feed on the sap produced by the injured plant.

Mature coconut trees can typically withstand feeding damage, but young plants under three years old often die. Over time, the mature trees are not replaced.

The population of these giant beetles grows quickly. An adult female beetle lays 70 to 140

As CRB bore through unfurled leaves the leave signs of damage that become apparent as the leaves unfurl. But this is not a definitive indication–other damage can leave V-shaped cuts. Photo courtesy of HDOA

eggs in its lifetime, depositing the eggs in mulch heaps or soft logs where they hatch into large whitish larvae. Even the larvae reach an impressive size: between 2 3/8 inches to just over 4 inches long. These brown-headed larvae with bluish-grey tail tints feel “squishy” and crawl on their sides. They lack any marking on the underside of their mouth.

Larvae mature through several stages over the next 2 to 3 months and finally form a cocoon where they become adult beetles. The adults hatch out at night, flying a few hundred feet to a nearby tree

While coconuts are the preferred host, the beetles can live on other palms, bananas, sugar cane, agave, even ironwood and taro.

Based on current surveys, the infestation on Oahu seems limited, with all known sites under active control. However, with any flying insect, certainty about the extent of an infestation can be challenging. Coconut rhinoceros beetles have not been detected on Maui. The key to preventing their establishment–and protecting coconuts, native and landscape palms in Hawai‘i–is detecting their presence early. You can help by looking for boring holes in the palm crown and the distinctive V-shaped cut on the leaves. Other types of pests can cause cuts and boring, but if you see these symptoms, an expert can help check it out.

To learn more, visit the Hawai‘i Department of Agriculture CRB update page at http://hdoa.hawaii.gov/pi/main/crb/. Submit pictures of damaged coconuts or palms via the Project Noah website. Look for the mission entitled “Help Save Hawai‘i’s Coconut Trees”- projectnoah.org/missions/18256600. You can also use, the online reporting tool at reportapest.org, or call the Hawai‘i Department of Agriculture’s Pest Hotline at 643-PEST (7378) toll-free from any island.

By Lissa Fox Strohecker. Originally published in the Maui News, April 13th, 2014 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Coconut palms are woven into the culture of the islands; a beetle threatens that connection

Detection of Coconut Rhinoceros Beetle on Maui Highlights Importance of Community Involvement in Pest Prevention

CRB spells trouble for Hawaii’s palms

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