March 2022: Fumigation and palm treatments showing positive results in reducing CRB trap catches

With new treatments in action, increased public awareness about CRB, and higher stakes than ever, we're excited for what this year holds. Mahalo for your interest in the current status of CRB in Hawaiʻi.


This article was initially sent as a portion of our quarterly newsletter. To join our list and be the first to know about new developments in the CRB Response, email info@crbhawaii.org or add your contact information at the bottom of any page on crbhawaii.org.

Trap Detections

This map shows where our traps have caught CRB in the past six months. Each black dot represents a trap that detected a beetle and the underlying color gradient approximates higher detection areas in yellow and lower detections in blue.


Last month for HISAM we highlighted the success of palm treatments in Pearl City Peninsula and Kapilina. After years of increasing trap detections in these areas, CRB catch numbers have decreased post-treatment (treatment timeframes are highlighted in green).


What do termites and CRB have in common? Fumigation treatments

Fumigation is a newly employed and effective option to treat CRB-infested breeding material. Using the same chemical and protocol as tenting a house for termite control, pest control companies contracted by the CRB Response are able to quickly treat large amounts of infested breeding material. This is one of the few techniques that terminate CRB at all life stages. Once the treatment was tested for safety and efficiency, it became clear that sulfuryl fluoride fumigation would dramatically increase our capacity to address CRB-infested material.


Sulfuryl fluoride (SO2F2) is an inorganic compound commonly used in structural fumigation. It is an easily condensed gas and resistant to hydrolysis, meaning that it breaks down slowly when exposed to water. The gas is injected into a tightly-sealed shipping container or tented roll-off bin. The gas reaches the nooks and crannies throughout the material, which few treatment methods can do effectively. Once the appropriate concentration is reached, the treated container remains untouched until treatment is complete. The material is then aired out during daylight hours before our team removes any compostable material to a hot composting facility for secondary treatment.


SO2F2 is the chemical used in fumigation. One component of the safety protocol is to place signage at the work site while the chemical is being used.


History:

CRB Response partners first tested fumigation as a treatment in April 2019. The program had just detected its largest breeding site to date on a small City & County parcel in Pearl City Peninsula. Through work with City and State agencies, an experimental trial of fumigation was developed. Although it seemed like a long shot, the Response contacted a company doing fumigations in Waialua to complete the experiment. Mulch was loaded into containers with various moisture contents and an assortment of CRB in all life stages. The trial was mostly successful against all stages of CRB except eggs. Since material with viable eggs couldn’t be removed from the site, it was decided that fumigation would not be a viable solution without more testing and optimization. Instead, with the help of the City and State, the entire breeding site was manually searched and turned, a labor-intensive survey method. This removed many CRB but the material had to stay on-site, leaving it vulnerable to reinfestation.


It wasn’t until a few years later that the CRB Response revisited fumigation as a treatment option. This time, the fumigant manufacturer was brought in to collaborate with testing for a dosage that would kill the eggs too. Our Principal Investigator, Dr. Michael Melzer, worked with the manufacturer and a local fumigation company to test higher concentrations of fumigant that would be effective against CRB eggs. Dr. Melzer procured a 40 cubic yard shipping container and outfitted it with a circulation system. The testing established a minimum dose of fumigant required to kill all CRB which is now incorporated into our fumigation treatment protocol.


Table comparing CRB Response breeding site treatments options for cost, labor, effectiveness, and quantity


Fumigation Container (pictured below):

Building a secure place to store and treat infested material was our first step in creating an effective fumigation treatment protocol. This sealed shipping container prevents escape and reinfestation of CRB and reduces chemical use and cost because it contains the gas better than a tent. It also includes permanent ports used to monitor gas concentrations during treatment. The container can hold about 18 cubic yards of material at a time. It is currently staged at the Pearl City Urban Garden Center, a central location for many of our treatment activities.


Infested material is loaded into 1 cubic yard landscaping bags and placed on pallets into the fumigation chamber. The chamber can hold 18 bags at a time.


On-site fumigation (pictured below):

On-site fumigation differs from container fumigation in a few key ways. First, a site is identified as appropriate for on-site fumigation. Requirements include appropriate space and terrain for roll-off bin delivery and loading and landowner approval. Large metal roll-off bins are delivered near the infested material. Depending on the capacity of the landowner and our team, the bins are loaded by tractor, bucket, and lots of sweat. Although the fumigation container has a lot of advantages, the biggest downside is it can be a lot of work to load material into smaller containers, transport and load it into the chamber, then unload the treated material into a roll-off bin. The on-site option allows us to load bins at the site, fumigate, and contract removal directly to a processing facility for secondary treatment. To date, we’ve treated 270 cubic yards of infested or likely infested CRB breeding material with on-site fumigation.


Mid-Pacific Pest Control setting up fumigation at the Waipio Soccer Park where 190 cubic yards of highly infested material were treated and removed.


Limitations:

Our biggest limiting factor is cost. Costs quickly add up when we consider how many cubic yards of material are currently CRB-infested or have a high likelihood of becoming infested. Other limiting factors are access and attitudes: because the treatment requires a significant investment in time, coordination, and property access, we can't afford to treat sites where breeding material may accumulate again. Lasting change in CRB infestation status requires a shift in community perspective toward using and generating CRB breeding material.

Future plans:

Fumigation shows promise as a thorough treatment that allows safer removal of infested material. Fumigation works best when paired with other treatments like palm injections, as it is unlikely all breeding material can be identified, collected, and treated in a given area. We're looking to work with landowners that can assist with some aspects of this treatment and commit to using less CRB breeding material overall, and using that material more quickly. Still, despite the groundbreaking treatment option fumigation provides, prevention is still the most efficient and cost-effective "treatment" strategy. It is our shared responsibility to reduce CRB risk and treat infested breeding sites. For guidance on green waste management and best practices, reach out to info@crbhawaii.org.