Methyl Bromide Alternatives
Plasticulture is important to the success of the vegetable industry in Florida. Soil fumigation using methyl bromide and chloropicrin has been a standard component for the plasticulture system. The EPA has legislated the phase-out of methyl bromide by 2005 and this has resulted in increased costs and reduced supplies. Effective alternatives to methyl bromide are needed to maintain profitability in vegetable production using plasticulture.
Why Alternatives?
Methyl bromide is a highly effective fumigant used to control insects, nematodes, weeds, and pathogens in more than 100 crops. Its primary uses are for soil fumigation, post-harvest protection, and quarantine treatments. The United States employs about 60 million pounds of methyl bromide each year - about 75% to fumigate soil before planting crops, about 11% to fumigate harvested commodities during storage and export, and about 6% to fumigate structures such as food processing plants, warehouses, and museums, as well as antiques and transport vehicles. The remaining 8% goes to the production of other chemicals.
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Under The Montreal Protocol on Substances that Deplete the Ozone Layer, methyl bromide was defined as a chemical that contributes to depletion of the Earth's ozone layer. The definition was based on scientific data. Accordingly, the manufacture and importation of methyl bromide will be phased out in developed counties as follows: 25% reduction in 1999, 25% reduction in 2001, 20% reduction in 2003, and complete phase out in 2005. In developing countries, consumption will be frozen in 2002 at 1995-98 average levels, followed by 20% reduction in 2005, and complete phase out in 2015. Exemptions for developed and developing countries include quarantine, critical uses, and certain pre-shipment uses.
Unless viable alternatives are found, US farmers and other users will be at a disadvantage when competing with agricultural products produced in developing countries where methyl bromide will continue to be available for several years after the US phase out.
Methyl Bromide Challenge
There is no known single alternative fumigant, chemical, or other technology that can readily substitute for methyl bromide in efficacy, low cost, ease of use, wide availability, worker safety, and environmental safety below the ozone layer. Research by the United States Department of Agriculture (USDA) indicates that multiple alternative control measures will be required to replace the many essential uses of methyl bromide. For pre-plant uses, such measures include combinations of fungicides, herbicides, and insecticides; other fumigants; and non-chemical alternatives, including cultural changes in cropping systems, resistant crops, and biological control. For some quarantine and export applications, effective replacements include irradiation, heat, cold, and controlled atmosphere treatments.
The effective application of a single alternative control measure or combination will generally be limited to a specific crop or use because specific crops have widely varying requirement and because of variations in target pests, soil types, climates, and state and local regulations. The development and adoption of alternatives to methyl bromide require four steps:
- Research
- Registration & Labeling
- Commercialization & Marketing
- Grower & User Adoption
Research Trials
Methyl bromide alternatives research trials are conducted at NFREC-Quincy and NFREC-Suwannee Valley facilities. Research trials have included:
- Evaluation of 1,3 dichloropropene + chloropicrin formulations, rates, and methods of application.
- Utilization of specialty mulches (VIF) to reduce fumigant rates and improve effectiveness.
- Evaluations of various fumigants and herbicide combinations in several vegetable crops.
- Evaluation of the role of coated paper mulches in fumigation trials.
- Screening of resistant varieties to soil-borne diseases.
- Developing soilless systems for outdoor production.
More Information
For more information on Methyl Bromide Alternatives, contact Bob Hochmuth, Steve Olson, Tim Momol or Jimmy Rich.