The California Department of Pesticide Regulation (DPR) released the fourth and final component of a multi-part study exploring alternatives to fumigant pesticides. The last report focused on the risks and benefits of pre-plant fumigants.
The research conducted by the California Council on Science and Technology (CCST) specifically looked at methyl bromide and three pesticides known as MITC generators – dazomet, metam-sodium, and metam-potassium. Similar to the findings from CCST’s previous reports, this report found that, while alternatives exist, there is no single alternative that can be used as a 1:1 substitute for methyl bromide or MITC generators. In particular, the cost and effectiveness of alternatives remain a significant barrier for growers. More crop- and region-specific research is needed to determine the efficacy of alternatives at commercial scale.
“DPR has made a strong commitment to sustainable pest management and finding alternatives to fumigants,” said DPR Director Karen Morrison. “We will continue to prioritize actions to protect human health and the environment through research and innovation.”
Both methyl bromide and MITC generators are restricted material pesticides in California – a group of high-risk pesticides that are strictly regulated to protect public health and the environment.
Methyl bromide is a soil fumigant that has been largely phased out of use in routine agriculture under the Montreal Protocol because of its ozone-depleting properties. The U.S. EPA only allows its use in a few circumstances – primarily for quarantine and pre-shipment of commodities, imported goods, and nursery propagation to prevent the introduction and/or spread of pests across borders. MITC generators are used to protect timber from rot and to reduce the spread of soil-borne pests between crop seasons.
DPR commissioned the independent study following the release of the Sustainable Pest Management (SPM) Roadmap to evaluate fumigant use and existing alternatives with funding from the California Budget Act of 2023-24. CCST’s reports focused on soil fumigants 1,3-D and chloropicrin, alternatives to sulfuryl fluoride, and post-harvest commodity fumigation.
DPR has also created two new committees to support implementation of the SPM Roadmap.
- The SPM Advisory Committee advises DPR on goals, tactics, policies, and partnerships that support the implementation of SPM statewide.
- The Scientific Prioritization and Review Committee (SPARC) will provide science-based recommendations to inform DPR’s transparent, data-driven process for identifying and addressing potential risks to human health and the environment from pesticide use.
DPR is also prioritizing alternatives to fumigants in its annual pool of SPM grant funding. For example, in May, DPR awarded over $600,000 to a project to evaluate the application of different combinations of soil fumigant alternatives.