Biosecurity Rapid Response Needed: CRB Detected on Maui and Molokaʻi

By Wayne Tanaka, Chapter Director | Reading time: 2.5 minutes

Early April brought the bad news we’ve been long bracing ourselves for: the highly invasive and incredibly destructive coconut rhinoceros beetle (CRB) has now been detected on Maui for the first time since 2023, and for the first time ever on Molokaʻi. 

As we have seen on Oʻahu and now on Kauaʻi, CRB is not only devastating to our iconic and cherished niu, but can wreak havoc on local agriculture, food security, ecological integrity, cultural practices, and our overall economy. With the ability to fly up to two miles in a day, reproduce rapidly in compost and mulch, and feed on a wide variety of plants, including hala, maia (banana), and even kalo, CRB can quickly spread and establish itself across the landscape. This makes the most recent CRB detections all the more alarming.

Fortunately, there may still be time to act and prevent CRB from becoming fully established on Maui and Molokaʻi.

First, those living, working, residing, or recreating within two miles of Kahului Airport, Molokaʻi Airport, and Kaunakakai Harbor should immediately inspect mulch and compost piles for CRB, including eggs and larvae. Larvae are typically large, white, and to curl into a “C” shape. If you find a suspected specimen, bag it, photograph it, freeze it, and report it to (808) 643-PEST or 643pest.org for identification. You can also contact the Molokaʻi/Maui Invasive Species Committee at (808) 480-8191 or molokaimisc@gmail.com.

Please do not transport live CRB eggs, larvae, or adults. Adults can chew through thin plastic bags, and moving live specimens, even unintentionally, can spread the pest to new areas.

It’s also important to note that CRB closely resembles the oriental flower beetle, which is widely established on Maui. Proper identification is critical to ensure follow-up and response.

Even if you are not in these areas, you can help. Spread the word, check public spaces for signs of infestation, reach out to elected officials, or even help coordinate other early detection efforts—reach out to us at hawaii.chapter@sierraclub.org for ideas! 

Second, monitor niu and other palms for signs of CRB damage. While feeding damage may not appear until months later, early detection is key. Look for v-shaped cuts in fronds, two-inch boreholes in the crown or trunk, or ragged edges on new leaves. If you see these signs, report them using the contacts above.  

Third, carefully inspect any purchased mulch, compost, or soil. These materials are known pathways for CRB spread, and even with regulations in place, infested products can still slip through.

For farmers and those managing large amounts of green waste, guidance from the CRB Response Team is available to help reduce the risk of breeding sites: crbhawaii.org/treatments-breeding.

Ultimately, our most powerful tool right now is awareness. Please share this information, as well as updates from the Hawaiʻi Department of Agriculture and Biosecurity, the Maui and Molokaʻi Invasive Species Committees, and the CRB Response Team with anyone who may be affected. Our ability to eradicate new invasive pests diminishes rapidly over time, getting as many people involved as quickly as possible in early detection efforts may be our best and last chance at preventing Maui and Molokaʻi from being overrun by CRB.   

While disheartening, the recent news of new CRB detections this month is not game over for Maui and Molokaʻi. However, it does call for rapid response and coordinated, all-hands-on-deck action, from government officials, to farmers, to grassroots community members, if we want to protect these islands from the most devastating consequences of this invasive pet. 

Our islands, and future generations, deserve nothing less.