Know your Zone
Coconut rhinoceros beetles breed in green waste and mulch. Our suggestions for managing green waste and mulch to prevent CRB vary depending on your proximity to known CRB populations on Oahu. Assess your risk by comparing your location
(either your property or where you source your mulch delivery)
to this heat map.
This heat map shows high trap catch areas in yellow with lower trap catch areas in blue. Trap catches are used to determine population locations and density.
Our current high-risk areas are concentrated in South Central Oahu, at Pearl City Peninsula, Iroquois Point, Waipio Peninsula, Ewa Beach, Mililani, and Kunia. These areas were defined due to high numbers of CRB detections in the area.
Contact the CRB Response for a FREE inspection of palms before they are felled, trimmed, or transported, and before moving of green waste. Transporting uninspected palms or green waste to areas on Oahu where CRB have not been detected could lead to a new breeding site or hot zone.
Sterilize Chipped Green Waste
Currently, the CRB Response recommends leaving green waste whole until it can be treated but previously chipped green waste piles are at risk for CRB infestation. For chipped green waste, we recommend re-chipping and removing outside the infested area, pesticide treatment (where applicable), heat treatment (greater than 130 degrees F), spread and dry, or storage in sealed durable containers the CRB cannot access. To develop a plan for your situation, contact the CRB Response.
New CRB infestations and outlier beetle catches on Oahu are likely caused by accidental transport of CRB in green waste or palms. Minimizing the transport of green waste and palms is a necessary step in preventing CRB spread across Oahu.
Chip and Remove
In high-risk areas, all accumulations of mulch are at risk of CRB infestation. To prevent this risk, chip the green waste at your site and transport it on the same day to an active composting facility. The CRB Response does not endorse specific companies, but we have verified that commercial composting facilities on Oahu (Hawaiian Earth Products and Island Topsoil) follow our best practices to prevent CRB. CRB are nocturnal and may reenter treated green waste, so chipped green waste should not be left in high-risk areas overnight.
CRB could be transported to a new area at any time and green waste accumulations across Oahu are potential breeding sites. Generally, low-risk areas on Oahu include the southern coast east of Moanalua, the windward coast, and the North Shore. CRB have not been detected on neighboring Hawaiian islands. The listed best practices will reduce your risk of spreading CRB out of high-risk areas.
Green waste or mulch transported across Oahu can contain CRB. Prevent the introduction of CRB to your home or business by sourcing your mulch on-site (ideal) or from another low-risk area. Similarly, do not stage green waste overnight in a high-risk area since CRB are nocturnal and may enter even treated green waste.
Large piles of decaying green waste or mulch are at risk of becoming CRB breeding sites. Prevent stockpiles by regularly treating mulch or depositing it in a green waste bin. In low-risk areas, we also recommend spreading mulch thin (less than 2” deep) and allowing it to dry (no irrigation) to protect against CRB infestation.
Keep Green Waste Whole
CRB prefer to breed in mulch with small particle size. Tree trimmings, felled trees, and other large green waste should be kept whole until you plan to treat it and remove it.
Heat to 130+ degrees
CRB cannot survive sustained temperatures of over 130 degrees F. Hot composting requires more than 100 cubic feet of mulch, proper moisture and carbon and nitrogen content, and regular turning (three times per week). The CRB Response does not endorse specific companies, but we have verified that commercial composting facilities on Oahu (Hawaiian Earth Products and Island Topsoil) follow our best practices to prevent CRB. Call the CRB Response to discuss non-commercial composting options.