VISALIA – Tulare County won’t see any genetically engineered mosquitoes flying around this summer after a Biotech company has taken a step back in the approval process.

On May 11, biotech company Oxitec, who created genetically engineered (GE) mosquitos, announced their voluntary withdrawal of their current Research Authorization (RA) application with the California Department of Pesticide Regulation (DPR). The application was to carry out field tests of its “friendly” lab grown mosquitoes in Tulare County. According to Kevin Gorman, Oxitec’s chief development officer they decided to withdraw because it was getting to be too late in the season and was no longer going to align with the overall timeline.

“There’s no point in leaving our application in to take up people’s time, energy and effort at this point, because there’s no prospect of a project in 2023,” Gorman said. “And that’s not really in line with our timelines, we have other commitments elsewhere, etc.”

The friendly mosquitoes are designed to reduce the population of Aedes aegypti, an invasive mosquito that has been plaguing the Visalia area for the last few years as well as other areas around the nation. The mosquitoes were engineered by the British biotech firm Oxitec with a self-limiting gene that infects female mosquitoes and prevents them from creating female offspring, leaving only male mosquitoes in the gene pool. Only female mosquitoes bite and are capable of transmitting diseases, which is why they are targeted and the engineered males will only mate with Aedes aegypti females.

The withdrawal of their application is more of a “pause” in the entire California process according to Gorman. He said this was all the decision of Oxitec, and was not for fear of rejection from the DPR, but simply to allow the company to focus on other areas that need the attention.

This will be the second year since Oxitec began this process in California that no GE mosquitoes will be released. However, this will be Oxitec’s third mosquito season in Florida, which is where the company will now focus the majority of their efforts. Oxitec’s announcement letter stated they will be submitting an application to release for future mosquito seasons:

In March 2022, The U.S. Environmental Protection Agency approved the release of the mosquitoes in Tulare County, Calif. as well as Monroe County, Fla. However, in April, the California program was postponed. Again in November of last year, members of the California legislature sent a letter to DPR asking for a delay in the release of the GE non-biting male mosquitoes. DPR still hadn’t made a decision, which is why they made the decision to withdraw.

According to Craig Cassidy, DPR information officer, DPR’s research authorization process entails a rigorous scientific review and risk evaluation process. That includes a determination of whether the pesticide product, the genetically engineered mosquitoes, is appropriate and safe for field testing.  Cassidy said because these mosquitoes are the first of their kind, the process can be even more rigorous.

“Due to the new nature of this technology, DPR received requests for a broader consideration of potential health and environmental impacts,” Cassidy said. “As a result, DPR added consultations with other government agencies to its review process and also included a process for public input and engagement.”

Gorman said the DPR wants to do a significant level of further outreach to stakeholders throughout the state. That additional outreach may include other genetically engineered science in addition to the research Oxitec has given them. Once the state has done the outreach they are wanting, Oxitec will come back and hopefully be able to move forward.

“[DPR] will continue to do outreach for some time to come,” Gorman said. “That outreach might extend not just in relation to Oxitec research authorization, but in relation to use of GM [genetically modified] products more generally, in California.”

Though there are no longer any applicants for genetically engineered mosquitoes in the state, DPR still plans to continue their research according to Cassidy. He said DPR is looking for opportunities for stakeholder engagement in the future regarding alternative pest management technologies.

“A key element is to improve DPR’s registration review process and prioritize and expedite safer, more sustainable alternative products to high-risk pesticides,” Cassidy said. “DPR is looking for opportunities for stakeholder engagement in the future regarding alternative pest management technologies.”

In Tulare County, Oxitec is working in collaboration with the Delta Mosquito and Vector Control District, based in Visalia. They were one of several who was chosen to participate in this pilot program. General manager of the district Dr. Mustapha Debboun said he sees this step as more of a pause in the overall process. He said he is hopeful this trial period will be approved and begin soon because of the benefits it could have in eliminating the disease carrying mosquitoes.

“It would be nice to at least try it, because their tool, their method, they are trying to see if it works,” Debboun said. “[Then] they can go to EPA, and commercialize a product to help us fight the mosquitoes.”

Despite the pause in the application process, Gorman said it does not mean Oxitec is giving up on California. They still have a lab in Visalia and they will continue to work with the Delta Mosquito and Vector Control District. Gorman said they appreciate the regulations, but of course it is disappointing. They will continue to support the DPR and they are looking forward to the future in California because it is a state that needs this type of support.

“Of course, it is a little bit disappointing that we didn’t get a final decision, approval or not, in time,” Gorman said. “However, at the same time, I have to say we appreciate DPR’s requirements and data regulators and state regulators. We abide by regulators, which is of course, subject to approval for everything that we do. Just as we are for the EPA for federal approval, so no issue on our side.”