Look for signs: Bore holes on palms, leaf cuts, or damage in compost/green waste. (Ref: CRB Hawaii, KISC video at 12:35)

Timing matters: Visible damage often appears weeks–months after feeding starts - report immediately and inspect nearby green waste.

Monitoring piles: Dig through compost or mulch every 4 months to find and remove large larvae.(CTAHR, Page 2)

Report here to 634PEST to help the state track infestations
Report here to AHK to get connected with Kaua‘i response teams; community sifters, dog sniffers, steaming services, pest control, and real on-island solutions.
Then tell your neighbors! Early action and open communication are key.

Green wastes includes: dead trees, stumps, mulch, wood chips, compost piles.

Properly Manage Materials

• Chip incoming CRB host materials within 48 hours.

• Properly compost CRB host materials by heating piles to at least 131 degrees Fahrenheit.

• Monitor finished materials at least every 4 months (visual check during turnover). Once compost cools to around 110 degrees Fahrenheit, it can be infested and is a good breeding material for CRB. CRB stays in piles for 5-6 months

• Do not stockpile or keep a mound of CRB host material. Routinely distribute around plants.

• Note thinly spreading materials have reportedly not been affective

• Netting piles: Highly effective - netting mulch piles traps up to 25× more CRB than pheromone traps. (Details on netting: CTAHR page 4 - 5)

Prevent the Spread

• Utilize or process CRB host materials that are already on-site for end use, eliminating the need to move potentially infested materials.

• Safeguard CRB host materials that have been properly composted or treated in completely sealed containers that prevent CRB entry. Containers made of metal, concrete or glass are acceptable. CRB can chew through many plastics.

• Ensure CRB host materials are still at acceptable temperatures or are subjected to effective treatment before being transported off site.

• If you receive CRB host materials, ensure it comes from a reputable source that follows CRB Best Management Practices. Ask suppliers to provide documentation of their CRB prevention efforts.

If you find CRB effective strategies:

1. Chipping and/or grinding

2. Hot compost every 4 months

If above strategies not feasible then:

• Incineration/Biochar: Kills CRB; biochar preferred for soil benefits and low

• Heat/Steam treatment: 100% natural and effective (Mr Lance’s Steam)

References: CRB Response, County of Hawaii Compliance Order

Net crowns: Use ½” monofilament netting around the crown - keep it fluffy and adjust monthly. Effective but labor-intensive.

Available online from Lee Fisher Fishing Supply,Memphis Net & Twine

References: CTAHR page 4 - 5

Keep palms healthy: fertilize appropriately and avoid over-pruning. Observations from response teams and community report that untrimmed trees often resist CRB better.
References: Daniel Anthony,Aloha Organic, untrimmed V trimmed by Brown Cannon

Essential oil spray: A non-toxic preventative solution. Per 1 gallon spray solution:

• 3oz Basil Oil,

• 1oz Clove Oil,

• 1oz Neem Oil,

• 60 drops of Premium Oleoresin Capsicum Extract,

• 1 tsp Hi-Yield spreader sticker (or sub with 1 tsp castile soap + 1-2 Tbsp coconut oil)

References:  CTAHR trials p38-44, Alberto Ricordi & Brown Cannon notes, CTAHR Paper, latest recipe informed by Brown Cannon to CRB Action

DIY Sprayer: Use a DIY sprayer for tall palms to reduce repeated climbs.

Instructions: Save Hawaiian Palms guide

Chemical Controls (Use with Caution)

Recommend reading Hawaii Invasive Species Council (HISC Chemical for CRB)

Important: Community sifters and dog groups won’t visit sites with recent pesticide use due to health risks

Crown Spray (e.g., pyrethrin-based sprays)
Short-term option but does allow you to continue to eat coconuts . Washes off easily but useful for non-accessible large groves or when you cannot reach trees to remove fruits and flowers. Drones can assist (Only permitted drone company on Maui - Aloha Aina Drones).

Reference: CRB Response Chemical treatments, KISC CRB training video

Trunk Injection (Imidacloprid and Acephate)
Use only in known infected areas. Short-term studies show low leaching risk if flowers/fruits are removed. Avoid repeated use due to potential long-term ecosystem impacts. Trees may still show CRB damage, but injection combined with collective action can reduce CRB populations.
Reference: CRB Response Chemical treatments Brown Cannon’s thoughts on injecting

Soil Drench (Imidacloprid)
Not yet proven effective (no formal testing). Same trimming precautions apply. Very risky of environmental leaching especially during rainy season or in places close to bodies of water.

Reference: CTAHR CRB Overview pg. 9

Traps are one of the most important tools for monitoring and reducing CRB populations. They help detect beetle presence early and can capture adults to slow spread in affected areas.

Some great DIY traps:

Brown Cannons

CRB Response

Where to buy all the resources

Key trap elements:

1. Netting (contact CRB Action Kauai for access to free resources)

2. Mulch (CRB are 25x more likely to go to mulch than a pheromone CRB Response)

3. Pheromone (study)

4. UV light (study)

• A Guam study found netting mulch piles caught 25x more CRB adults than pheromone traps and other trapping methods (Moore et al. 2014).

• CRB Responses statement showing lack of evidence that traps attract CRB to new areas