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CRB Best Management Practices: LANDSCAPE OPERATIONS & MAINTENANCE GUIDE

Posted on Mar. 4, 2025  /  Best Practices, Invasive Species, Plant Pests, Arboriculture  /  0

By: PBR Hawaii & Tree Solutions Hawaii

1.0  INTRODUCTION

The coconut rhinoceros beetle (Oryctes rhinoceros) (CRB) is an invasive beetle from Southeast Asia. CRB has been present in Hawaii since 2013, but damage has noticeably increased across the island of Oahu within the last few years. It poses a serious threat to palms, including but not limited to coconut, phoenix, royal, and fan palms (loulu). The beetle has also been observed in non-palm species such as banana, kalo, and ulu. CRB most commonly breed in the trunks of dead palms, greenwaste debris, and mulch or compost piles, but larvae have been found in the crowns of live palms or in soils. CRB adults bore into the center of the palm crown to feed on the exuded sap, which causes damage to the developing leaves. Damaged fronds will exhibit a characteristic “V” cut where the CRB has bored into the immature leaves, or a deformed smaller frond for fan and loulu palms. CRB boring can cause slower growth, lower yield, frond damage, and palm death. Removal of dead palms is recommended for safety reasons and to reduce CRB breeding habitat, but it is not generally recommended to remove living palms in good health. CRB does not inhabit palms long-term, so reducing amounts of palms may cause further damage to existing palms or drive CRB to new areas.

Figure 1. Adult CRB beetle. Source: Coconut Rhinoceros Beetle Response.

A comprehensive operations, management, and maintenance plan is necessary to keep palms alive in the landscape and to prevent the further spread of CRB. This document has been prepared to serve as a set of guidelines for the long-term maintenance of an attractive landscape. Guidance for this document has been provided by experts from the University of Hawaii and the Hawaii Department of Agriculture.

To improve the knowledge base within the Landscape Industry and to ensure workers are following the most current recommendations by the expert agencies, workers at nurseries, tree care companies, and landscape services that handle palms and other plants susceptible to CRB should receive training. The free training workshops will be provided through the University of Hawaii, CTAHR Cooperative Extension, and the workers will receive a certificate of attendance to document that the pesticide applicant has completed the training. The function of maintenance standards and training is to promote a healthy landscape with qualified applicators.

At all times, Best Management Practices (BMP) should be acknowledged and followed for the use of all fertilizers, chemicals, equipment, and irrigation systems. All products shall be used in accordance with product labels - the label is the law and shall supersede any information in this document. As more research emerges and new treatments become available, this document will be amended and updated to reflect the BMPs recommended by authorities on CRB management. Please refer to the CRB Response - Hawaii website for further resources related to CRB and for updates to treatments: crbhawaii.org

 

2.0 SCHEDULE FOR PLANT MATERIAL PREPARATION

TASK

DESCRIPTION

Pre-Installation – In Nursery [Refer to Section 3]

Primary Treatment

Nursery to do prophylactic treatment of palms 3 months before transport with trunk injection or soil treatment.

Import/Export
off island

All interisland transport of CRB Host Material must be inspected by Hawai‘i Department of Agriculture (HDOA) staff and requires compliance agreement with HDOA. All material transport shall follow current regulations.

 

Export: Nursery to quarantine new plants and materials minimally 72 hours prior to export, particularly with materials originating from O‘ahu or Kaua‘i. Conduct thorough inspection of roots, trunk, and foliage (details below).

 

Import: Nursery to quarantine new plants and materials received from an infested island for 72 hours and do thorough inspection of roots, trunk, and foliage (details below).

Quarantine & Inspection

 

Details in Section 3.0

Pre-Installation

During quarantine, inspect root ball, trunk, and crown before moving offsite.

A synergist spray of Piperonyl Butoxide* can be used to induce CRB out of crown during inspections. If CRB are detected, remove insects and return plant to quarantine for 48 hours.

 

A pyrethroid** contact-insecticide can be applied to the affected parts if CRB are found, and to prevent additional CRB from chewing the palms.

Re-inspect palm before moving off-site.

Secondary Treatment – In Nursery

Regardless of CRB detection, spray crown with pyrethroid** prior to transporting.

 

Post-Installation- On Site [Refer to Section 4]

Maintenance Inspection

After installation, visually inspect palms from the ground every 30 days for bore holes and new frond damage. Use binoculars to look at tall palms.

 

Inspect CRB Host Material every 3 months (turnover or spot check).

Maintenance Treatment

Crown spray pyrethroid product every 3-4 months or during maintenance pruning.

 

Inject palm with recommended insecticide (Imidacloprid 10% OR Acephate 97%). The Imidacloprid chemical can be applied every 6 months (maximum) or at least 12 months (minimum). Acephate (97%) can be applied every 12 months. The chemicals can be rotated on an annual basis to reduce the resistance in CRB.

 

*Piperonyl Butoxide (PBO) on its own is not an insecticide, but will induce CRB out of palm. PBO is in select pyrethroid insecticide products such as OneGuard or CropSpray.

**Pyrethroids- These are contact insecticides, which can be applied to prevent CRB damage or if CRB were identified in the crown. Select pyrethroid sprays are not approved for nursery use (i.e. OneGuard). Follow the label and use a pyrethroid for nursery application (i.e. CropSpray [which has PBO) or Evergreen [no PBO]). 

3.0 PRE-INSTALLATION OF PALM (REFER TO ATTACHMENT 1 FOR LOG)

At the nursery, stage the palm so that the root ball, trunk, and crown may be examined.

Figure 2. Inspect the root ball, trunk, and crown of the palm. Source: Coconut Rhinoceros Beetle Response.

Inspection Methods:

Root Ball

If potted, submerge pot for 48 hours and collect/report any CRB found.

If not potted, clear soil as best as possible around roots and inspect for grubs and adults.

Do not transport if grubs or adults are found. Remove and destroy any grubs found.

Trunk

Inspect any and all holes with special attention to the base of the palm. Spray with Piperonyl Butoxide. * Do not move if rotting material or borer holes are found.

Crown

Inspect entire crown and pay attention to the spear. If the spear shows signs of feeding, inspect the base of the spears for signs of CRB boring and remove beetles. Recommended spray with Piperonyl Butoxide* to induce the CRB out of the palm. Always report palm damage whether or not the palm will be moved. Do not transport if spear severely damaged because palm may not survive.

Crown Treatment

Treat crown with pyrethroid** to kill any CRB in palm, and CRB that are attracted to and land on the palm.

 

Figure 3. Inspect the entire crown and spear. If the spear shows signs of feeding, inspect the base of the spears and crowns for signs of CRB boring and remove beetles. Source: Coconut Rhinoceros Beetle Response.

*Piperonyl Butoxide (PBO) on its own is not an insecticide, but will induce CRB out of palm. PBO is in select pyrethroid insecticide products such as OneGuard or CropSpray.

**Pyrethroids- These are contact insecticides, which can be applied to reduce CRB damage or if CRB were identified in crown. Select pyrethroid sprays are not approved for nursery use (i.e. OneGuard). Follow the label and use a pyrethroid for nursery application (i.e. CropSpray [which has PBO) or EverGreen [no PBO]).

 

4.0 MAINTENANCE (POST-INSTALLATION) OF PALM (REFER TO ATTACHMENT 2 FOR LOG)

Inspect trees every 30 days after installation.

  • Visual inspection from the ground. Use binoculars to inspect the crowns of tall palms.
  • Look for bore holes in the crowns of trees at the bases of fronds and for the characteristic frond damage of 45-degree, v-shaped cuts (coconuts and large palms) or small deformed fronds (fan and loulu). Leaflets will have scalloped edges.
  • Inspect CRB Host Material every 3 months (turnover or spot check).
  • Aerial inspections can be done when palms are being pruned.

Palm Treatment (Details in section 5.0)

  • Re-treat each palm on the following schedule:
    • Crown Spray Application: during regular maintenance pruning (every 3-6 months) of pyrethroid with long residual (i.e. OneGuard).
      Note: EverGreen has residual of up to 1 week.
    • Trunk injection of systemic insecticide: Imidacloprid 10%. Select Imidacloprid products can be injected every 6 months in accordance with the product label (Ima-Jet 10). The minimum application of Imidacloprid is every 12 months. Acephate 97% (ACE-jet) can be applied as necessary when CRB damage is first observed on palms. Adhere to the label for each product’s application rates. 
      OR Soil drench of systemic insecticide: Only if few palms on property- adhere to label application rates. Application rate is every 12 months.
    • Option to install physical barriers (netting) at the base of fronds- management required on a 2-3 month schedule 
  • It's critical to maintain palms free of flowers and fruits if the palms are treated with Imidacloprid or Acephate products due to the potential toxicity to pollinators. Take extreme care to not spray flowers with pyrethroid due to its toxicity to insects. 

Figure 4. Always document and report signs of CRB damage. Source: Coconut Rhinoceros Beetle Response

 

 

5.0 TREATMENT BEST PRACTICES FOR PALMS (REFER TO ATTACHMENT 3 FOR LOG)

Integrated pest management should be done in the following order:

1) Prevention (i.e. inspection prior to palm installation)

2) Cultural/Sanitation (maintain areas free of breeding habitat)

3) Physical/Mechanical (install barriers in palm crown)

5) Chemical (for non-consumption fruiting palms only)

If CRB and/or its larvae are found on the plant materials, the following management practices can be implemented. Note that there is no single treatment that completely eliminates CRB. Combining multiple practices is most effective.

Chemical/Pesticide Best Practices

  • Trunk injection (systemic)
    • Chemical Application:
      • Apply Acephate 97% for faster kill of resident CRB adults (for ornamental trees only). No application is permitted when the plant has flowers, per product label).
      • Apply Imidacloprid 10% for long-term protection (for ornamental trees only. No application is permitted when the plant has flowers, per product label)
      • Not restricted-use pesticides, but applicators must be trained on using equipment properly.
      • Inject at base of the palm where not visible. Success has been reported with drilling and injecting into spike holes. Injections are possible in adventitious root zones. 
      • No per-acre limitations for application.
      • Not to be applied in conjunction with a soil drench
  • Application schedule:
    • The residual duration for Acephate is 1-2 months. Repeat applications as necessary if damage reappears.
    • Maximum application every 6 months for Imidacloprid (recommended).
      • As of November 2024, only Ima-Jet10 is labeled for 6-month application rates.
      • Adhere to label rate and timeframe for other Imidacloprid products.
    • Minimum application every 12 months for Imidacloprid or Acephate
      • Consider switching between chemicals annually or every 2 years to reduce potential resistance in CRB.
  • Management:
    • Requires trimming of flowers and fruits every 4-6 months to protect pollinators (best management practice) and no consumption of fruits within 1 calendar year (per product label).
    • Takes 1-2 weeks (Acephate) or 2-4 weeks (imidacloprid) to uptake and be effective. The residual duration is 6 months to 1 year.
    • CRB needs to feed on palm to ingest chemical- palms may still show signs of damage even after injection.
    • Large-scale application is needed for effective treatment.

  • Root drench/chemigation
    • Chemical Application:
      • Imidacloprid (No application of product is permitted when plant has flowers, per product label).
    • Not a restricted-use pesticide.
    • Liquid form- use bucket to mix with water and drench root zone, or use soil probe with tank mix. Adhere to the label for per-acre application rates.
    • Granular form- spread around the root zone of palm. Adhere to the label for application rates.
    • Similar mode of action as trunk injection, used primarily for short trees or few trees on the property.
    • Not to be applied in conjunction with a trunk injection.
  • Application Schedule:
    • Maximum application every 12 months.
  • Management:
    • Requires trimming of flowers and fruits every 4-6 months to protect pollinators (best management practice) and no consumption of fruits within 1 calendar year (per product label).
    • Takes 4-6 weeks to uptake and be effective. The residual duration is 6 months to 1 year.
    • CRB needs to feed on palm to ingest the chemical- palms may still show signs of damage even after injection.
    • Adhere to label application rates- do not exceed the allowed amount of active ingredient per acre per year, as directed by the product label.
    • No application near water (minimum 25 ft. from water).

  • Canopy Spray
    • Chemical Application
      • Pyrethrin (i.e. EverGreen- botanical derived, organic) or Pyrethroid (i.e. OneGuard or CropSpray- synthetic).
      • Not a restricted-use pesticide.
      • Mix in a hand-sprayer for climbers, 1 or 2-gallon wand sprayer for aerial lift, or backpack sprayer for short trees that can be reached from the ground.
      • Apply only to frond bases in the crown where CRB will bore in. Do not apply to the leaves on frond. 
      • PPE is glasses, gloves, long pants, shoes & socks.
    • Application Schedule:
      • Apply every 3-4 months, when trees are pruned.
      • Degrades with sun and rain, may need more frequent application based on the weather in the application area. 
    • Management:
      • Contact-insecticide, so will kill/paralyze all insects that come in contact with the sprayed area. Do not apply directly to flowers.
      • Can be applied in conjunction with trunk injection OR soil drench.
      • Residual duration is 1-3 months.
      • No application near water (streams, ocean) due to runoff potential.

Non-Pesticide Best Practices

  • Physical Barriers 
    • Traps
      • Pheromone traps
      • Install in non-palm species or on the ground away from palms and other CRB host plants (i.e., banana, hala, kalo, ulu, etc.)
    • Netting
      • Prevents CRB from accessing the crown of the tree to bore.
      • Management to reset netting is required every 2-3 months.
      • Ensure netting is loose/fluffy.
      • Ensure the net hole size is no greater than 1-2 inches stretched.

 

 

6.0  MANAGEMENT OF GREENWASTE (I.E. BREEDING SITES)

CRB host sites include materials beyond live palms. Breeding sites have been found in dead palm and tree stumps, compost, mulch, trimmings, fruit, and vegetative scraps. When possible, avoid the accumulation of these materials. Always treat infested material before removal and properly treat green waste.

CRB INFESTED DEBRIS

Fresh (Tree and Palm Waste- branches, logs, stumps, fronds, leaves)

Material can be moved within 30 days of removal from a live plant.

Treated

Treated material can move within 48 hours of treatment. Options for treatment include heat treated (core temperature 131 degrees Fahrenheit), chipping or grinding (all material is run through a chipper or grinder), or fumigation [material is fumigated with sulfuryl fluoride to 2000 Concentration -Time (CT)].

Secure

Material may be moved if it is sealed overnight, remains in a CRB safe container, and if it was CRB-free when loaded.

Processing Site

Material may be taken directly to a certified processing facility where it will be ground within 72 hours of transport and heat treated to 131 degrees Fahrenheit.

If CRB and/or its larvae are found, a kill-treatment of infested debris is required on a 3-month cycle. The CRB Response recommends removing unnecessary greenwaste and mulch off-site as quickly as possible and directing material to a certified processing facility, using proper transport methods. Refer to the CRB Response website for the current transport details and processing facilities.

TREATMENTS AND BEST MANAGEMENT PRACTICES

  • Processing and/or Removal of Greenwaste
    • Kills CRB
      • Fine Chipping
        • Chip infested whole un-processed material (branches, logs, fronds)
        • Do not store chips- keep material whole until it can be chipped, removed, or used.
      • Heat treatment/ Hot Compost
        • Aim for core temperature 131°F/55°C (minimum 115°F).
        • Note- material can be re-infested once it cools.
      • Fumigation
        • Fumigation with sulfuryl fluoride.
        • High-throughput treatment of infested material.
        • Effective at devitalizing CRB eggs.
        • 2000 Concentration-Time (CT) treatment resulted in complete devitalization.
        • 1500 CT treatment resulted in 1-2% egg survival.
        • Can be used for treating material from small breeding sites or for off-island shipment.

 

  • Slows CRB Growth
    • Spread material thin
        • Spread mulch and compost thinner than 2 inches deep.
        • Allow material to dry and for predators to find CRB.
    • Search and turn
        • Dig through the material and remove CRB.
        • Unreasonable for large piles but manageable for small piles.
        • Adopt a 3-month turn and inspection schedule.
    • Net piles
        • Apply thin gill netting over compost piles to trap beetles entering the pile to lay eggs, and beetles emerging from the pile.
        • Do not stretch the net- beetles can bore through and cut the net. Keep it light and fluffy to trap the beetles.
        • Regularly inspect the net and maintain it free of holes. 

 

 

References:

CRB Response https://www.crbhawaii.org/

CRB Statewide Communication Plan https://dlnr.hawaii.gov/hisc/files/2024/03/Hawaii-CRB-Communications-Plan-2024.pdf

 Expert input and review by the State of Hawaii:

Hawaii Department of Agriculture - Darcy Oishi

University of Hawaii at Manoa - Dr. Michael Melzer, Dr. Keith Weiser, Dr. Zhiqiang Cheng

University of Hawaii at Manoa Cooperative Extension -  Alberto Ricordi

PBR HAWAII & Associates, Inc., based in Hawaiʻi for over 50 years, delivers high quality, effective, and inspiring built spaces. Our staff of Landscape Architects, Designers, Planners, and Graphic Designers, is intimately involved with the planning processes and design requirement necessary to implement projects of all scales.
Tree Solutions Hawaii is a small family consulting firm with over 50 years of experience, focused on providing science- based arboriculture and environmental services. 

APPENDIX I. Select Product Labels

Select Product labels:

Trunk Injection

Ima-Jet 10: https://arborjet.wpenginepowered.com/wp-content/uploads/2021/03/IMA-jet10_websitelabel_9152020.pdf

https://arborjet.wpenginepowered.com/wp-content/uploads/2024/04/IMAjet10-Insert8.5x11_2ee-2024.pdf

Ace-Jet: https://arborjet.wpenginepowered.com/wp-content/uploads/2023/01/8.5x11ACEjetInsert_012023_websitelabel.pdf

Xytect 10%: https://rainbowtree.widen.net/s/7pqtrnkpnh/xytect-10-insecticide-label

Imicide: https://www.mauget.com/wp-content/uploads/2015/07/Imicide.pdf

Soil Drench

Merit 75 WSP: https://labelsds.com/images/user_uploads/Merit%2075%20WSP%20Label%2010-25-16%20AV1.pdf

Crown Spray

OneGuard: https://www.mgk.com/product_docs/15435/ldE6I001.pdf

EverGreen: https://www3.epa.gov/pesticides/chem_search/ppls/001021-02560-20170419.pdf

CropSpray: https://www3.epa.gov/pesticides/chem_search/ppls/000432-01033-20110922.pdf

DemonMax: https://www.syngentapmp.com/current-label/demon%20max

MustangMaxx: https://www.cdms.net/ldat/ldAMJ024.pdf

 

APPENDIX II. ATTACHMENT 1. CRB PALM PRE-INSTALLATION LOG

APPENDIX II. ATTACHMENT 2. CRB MAINTENANCE LOG

APPENDIX II. Attachment 3. CRB TREATMENT LOG

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