DRP releases final findings on fumigant alternatives study

The California Department of Pesticide Regulation (DPR) released the final report in a multi-part study examining alternatives to pre-plant fumigants, concluding that no existing alternative can directly replace methyl bromide or methyl isothiocyanate (MITC) generator pesticides on a one-to-one basis. 

The independent research, conducted by the California Council on Science and Technology (CCST), evaluated methyl bromide and the MITC generators dazomet, metam-sodium and metam-potassium. The report found that while alternatives are available, their cost and effectiveness remain significant barriers to adoption. It also concluded that additional crop- and region-specific research is needed to evaluate alternatives at commercial scale.

“DPR has made a strong commitment to sustainable pest management and finding alternatives to fumigants,” Karen Morrison, DPR director, said. “We will continue to prioritize actions to protect human health and the environment through research and innovation.”

Methyl bromide and MITC generators are classified as restricted material pesticides in California. Methyl bromide has largely been phased out for routine agricultural use under the Montreal Protocol because of its ozone-depleting properties, although the U.S. EPA allows limited use for quarantine, preshipment and nursery propagation purposes. MITC generators are used to protect timber from rot and reduce soil-borne pests between crop seasons.

The study was commissioned following the release of California’s Sustainable Pest Management Roadmap and funded through the 2023-24 California Budget Act. Previous reports examined soil fumigants 1,3-D and chloropicrin, sulfuryl fluoride alternatives and postharvest commodity fumigation.

DPR also announced the formation of two committees to support implementation of the roadmap and highlighted more than $600,000 in grant funding awarded in May for research evaluating combinations of soil fumigant alternatives.