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Integrated Pest Management
Integrated pest management (IPM) is a framework for decision making and planning that is intended to maximize the level of pest control and minimize risks to the environment, people, and economic costs. IPM is essentially employing every available method for pest control in a balance that maximizes efficiency and efficacy. The only downside to IPM is that in some cases it may take more labor, time, money, or expertise compared to less comprehensive strategies. Very often it is less expensive, more effective, and safer than other approaches.
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Using an IPM approach begins with learning all the tools that are available for control of the pest in several categories. The typical IPM categories are biological, cultural, physical, and chemical.
Putting more resources into a single approach usually results in diminishing returns, bigger impacts to the environment, higher costs, and/or more risk to human health. Using techniques from all of these categories can act synergistically to be more effective than any single approach. ​
CRB management requires broad adoption of best practices and treatments across entire neighborhoods and regions to be effective. Read more about how to coordinate CRB management in your neighborhood here.
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Let’s begin by explaining each pillar of IPM then listing what is available for CRB control in each category.
Prevention
Prevention is the most important strategy because it typically takes the least time, effort, cost, and has few impacts. This is not an option if the pest is already present in your area. Pests are often brought in accidentally on plants, building materials, clothing, vehicles, and various commodities. Examples of prevention include quarantines on goods from infested areas, inspections of incoming materials, boot brushes at trailheads to remove weed seeds, or educating shippers and consumers about high risk commodities.
For CRB the biggest prevention measures are sourcing mulch, compost, plants with soil, and palms from areas without CRB. If you must import material that could have CRB, inspection and treatment to kill any CRB is the safest practice. CRB adults can fly into vehicles and larvae can be in residual mulch or compost in trucks. Search and clean vehicles before moving them from an infested area to a non-infested area.
Cultural Control
Cultural control means changing the conditions where the pest is found to make it less hospitable for the pest. This includes actions like changing watering levels, removal of overripe fruits, increasing airflow, removing plant waste, pruning, or tilling.
The most impactful cultural control for CRB is removing and/or sanitizing breeding material in and near the area you want to protect. This includes mulch, compost, stumps, plant trimmings, potting soil, and other decaying plant material. CRB spend the large majority of their life in this material and most of the biomass of beetles comes from the nutrition they obtain from the breeding material. Material that cannot be removed can be heat treated, fumigated, chipped, contained, submerged, or dried to reduce CRB risks. Refer to our breeding site treatments page for more details.
Reducing irrigation of decaying plant material like mulch and soil can reduce the suitability of breeding material since CRB prefer moist material with active decomposition. Removing accumulations of plant waste from the tops of palms is a minor control that limits breeding in the crowns of palms.
Physical Control
Physical controls are typically barriers or traps that keep the pest away from a protected area or commodity. Examples include a water moat around a greenhouse, weed matting, a baited trap, heat treatments to kill the pest, or netting to exclude the pest from a host.
CRB traps are not very effective at controlling populations on their own but can be part of an IPM strategy. The most effective traps use breeding material or a living palm crown as bait. Pheromones are an additional attractant that can be used alone or with other attractants and are most effective when CRB populations are low. There are several trap types but the most effective is monofilament netting placed over moist decomposing mulch or compost. Netting can also be placed in the crowns of palms or other hosts. Netting placed on fences with a pheromone lure can also be used as a trap.
Biological Control
Biological control is the use of other organisms to control the pest. This is often the introduction of predators, parasites, or pathogens. General examples include things like bringing in goats to eat pest grasses, releasing ladybird beetles to eat aphids, releasing a parasitoid wasp to destroy insect eggs, or releasing a virus that specifically targets a pest species.
For CRB, there are limited biological controls available in Hawaii but researchers at UH have applied to import the currently most effective biocontrol for testing. This is oryctes nudivrus and it is a virus that infects CRB, spreads naturally once introduced, and has suppressed populations in other countries to manageable levels. Fungi in the Metarhizium genus have also been used to control CRB but have been less effective than nudivirus. Metarhizium requires reapplication to breeding sites multiple times per year for maximal efficacy. Metarhizium is not available for sale in Hawaii and is not currently approved for use as a biopesticide in Hawaii.
There are several predators in Hawaii including pigs, chickens, mongoose, rats, and egrets. Several of these are undesirable especially on farms but the best general approach to promote predator activity is to spread out breeding material to allow easy access and foraging. If pigs or chickens are in an enclosure, infested material can be put in the enclosure to get some control.
Chemical Control
Chemical controls are the application of a toxic or repellent substance to kill or repel the pest. Examples include applying synthetic or natural insecticides like neem oil to a plant, laying out bait with rat poison, spreading boric acid in kitchen cabinets, or fumigation of a house for termites.
There are a number of natural and synthetic substances that are toxic to CRB including natural pyrethrins and plant oils like basil oil as well as synthetic pyrethroids, neonicotinoids, and organophosphates. The choice of which chemicals to choose depends on the location, land use, budget, and where you want to apply. Refer to our insecticide and palm treatment guide for more detailed information on which treatments might work well for CRB at your site.