Impact of the ban on the soil-applied fumigant methyl bromide

Authors: Rosskopf, Erin; DI GIOIA, FRANCESCO - Pennsylvania State University; VINCENT, ISAAC - University Of Florida; Hong, Jason; ZHAO, XIN - University Of Florida

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2024
Publication Date: 6/19/2024
Citation: Rosskopf, E.N., Di Gioia, F., Vincent, I., Hong, J.C., Zhao, X. 2024. Impact of the ban on the soil-applied fumigant methyl bromide. Phytopathology. 114(6): 1161-1175. https://doi.org/10.1094/PHYTO-09-23-0345-IA.
DOI: https://doi.org/10.1094/PHYTO-09-23-0345-IA

Interpretive Summary: In 1992 the United States became a party to the Montreal Protocol on Substances that Deplete the Ozone Layer, which was a universally-signed agreement to reduce or eliminate the use of more than 100 ozone depleting substances. One of these was methyl bromide, which was used to fumigate soil for the control of pests of numerous important annual and perennial crops, particularly in California and Florida. The loss of this important soil fumigant has had a negative impact on the production of a number of fumigant-dependent crops, with Florida winter vegetable producers incurring the greatest losses. Alternative fumigants have been developed but none are considered to provide the broad-spectrum of pest control that was achieved using methyl bromide. Although the loss of production has been a significant drawback of the ban of this chemical, there has been a significant positive impact on the ozone hole and large reductions of bromine in the stratosphere. In addition, it was necessary to create multidisciplinary teams working together to address the many issues that resulted from the ban and numerous funding programs were made available to develop cropping systems that are not dependent upon chemical inputs.

Technical Abstract: The loss of the soil fumigant methyl bromide (MeBr) has had both positive and negative effects. The unfortunate consequences of the loss of this easily applied, broad-spectrum biocide include a significant loss in Florida fresh-market tomato production as well as reductions in other, primarily Florida, commodities. Pathogens and weeds previously controlled by MeBr are often not controlled as well with alternatives and emerging pathogens continue to be identified. None the less, applauded as one of the most effective environmental agreements to date, the universally accepted Montreal Protocol on Ozone Depleting Substances has had a significant effect on the environment, reducing the release of halogenated compounds from anthropogenic sources enough to mitigate global warming by 1.1 °C by 2021. The funding associated with various MeBr transition programs has increased collaboration across scientific disciplines, commodity groups, industry, and regulatory agencies. Chemical alternatives and improved application strategies, including the development of gas-retentive agricultural films, coupled with sound efficacy data and grower ingenuity have resulted in the sustained production of many of the impacted crops, although there has been some loss of acreage, value has increased, allowing production to continue. The loss of a single, broad-spectrum tool for pest control has led to an increased understanding of the specific pest complexes impacting these at-risk crops, as well as new, more biologically based tools for their control, while increasing our understanding of the role of the soil microbiome in pest control and crop production.