The Facts About Methyl Bromide

What is it?
• Methyl bromide is used as a pre-plant soil fumigant to control diseases and pests in agriculture. It is also used for quarantine (to prevent the introduction or spread of pests), pre-shipment (to meet phytosanitary and sanitary requirements of importing or exporting countries).

• It is used by 100 agricultural commodities in the United States. Other countries use it for structural fumigation applications as well.

• While alternative fumigants are available today, methyl bromide is the most effective product for the control of plant pathogens and other soil borne pests.

• Scientists have determined that less than one percent of the ozone-depleting potential in the upper atmosphere comes from man-made methyl bromide. Additionally, a number of materials banned internationally, such as CFCs (used for air conditioning) and halons (fire retardants), are more significant contributors to the ozone problem. While methyl bromide has a half life of only two years and is a slight contributor to ozone depletion, these other chemicals, although no longer used, are still far more deleterious to the ozone layer because of their long persistence in the atmosphere due to half lives of up to 80 years.

• Methyl bromide is also released from natural sources like the ocean, wetlands and many plants.

Phase Out and Critical Use Exemption
• The Montreal Protocol is an international treaty created in 1987 to protect the world’s ozone layer. In 1992, methyl bromide was identified as an ozone-depleting substance by the Protocol and a provision was added to phase-out the production of methyl bromide by 2005 in developed countries and 2015 in developing countries. This provision allowed countries the opportunity to apply for a Critical Use Exemption (CUE) if the country had conducted sufficient alternative research but was still unable to find a viable, safe alternative to methyl bromide.

• Because the critical use exemption was approved by the Environmental Protection Agency and the UN, the use of methyl bromide in the United States has been approved for several critical agricultural uses for 2005 and 2006.

• The California strawberry industry is working within the framework of the Montreal Protocol to address the need for a safe and effective pre-plant soil fumigant. The Commission is working closely with the U.S State Department, the Environmental Protection Agency, and scientific committees within the Montreal Protocol to address the industry’s need for methyl bromide while following the guidelines of the Montreal Protocol. Through the provisions of this protocol, California strawberry fruit production and many other agricultural sectors in the US and around the world have been identified by the Parties to the Montreal Protocol as having critical needs for methyl bromide due to the lack of suitable alternatives.

The Transition to Alternatives
• Methyl bromide has been completely discontinued in 35 percent of California’s 33,000 acres of strawberry fields. The remaining acreage is being transitioned as quickly as possible without compromising responsible production practices.

• Per acre use of methyl bromide has decreased from 195lbs/acre in 1992 to 130/acre in 2003 while the use of alternatives has increased from 84lbs/acre in 1992 to 156/acre in 2003.

• Besides regulatory and economic challenges, the technical feasibility of switching fumigants is not easy. When changing standard growing practices, a grower has many environmental factors to consider, including soil type, disease pressure, groundwater availability and whether there are surrounding wetlands.

• Certain typography such as hillside sloping can limit the effectiveness of methyl bromide alternatives and increase production costs. Without effective alternatives, the loss of methyl bromide could make production unprofitable for a significant number of growers, resulting in fewer strawberries available.

Methyl bromide alternatives being used by the California strawberry industry include:
Chloropicrin – this fumigant is used to control soil-borne diseases by controlling pathogens that attack the strawberry plant’s root system and crown, and is applied by either drip or broadcast/shank. This fumigant also has some weed control activity.

Telone – this fumigant is applied by shank/broadcast and controls soil-borne diseases. It also provides good control over the nematode population.

Inline – A mixture of telone and chloropicrin, this fumigant is applied in drip irrigation. A new alternative to methyl bromide, inline provides higher efficiency.

Metam sodium – is used mainly for weed control in combination with either Inline or chloropicrin and is applied by either drip or broadcast/shank.

Research
• Under the U.S. Department of Agriculture's (USDA) Methyl Bromide Alternatives Program (http://www.nps.ars.usda.gov), agricultural and forestry leaders from private industry, Universities, state, and federal agencies have worked together to develop viable alternatives to methyl bromide.

• From 1993 through 2004, the USDA Agricultural Research Service has spent approximately $172 million in an aggressive research program to find alternatives to methyl bromide. Through the Cooperative State Research, Education, and Extension Service, USDA has provided an additional $19.7 million to state universities for methyl bromide replacement research and education.

• In addition to these federally supported activities, the California Strawberry Commission has funded more than $10 million for additional extensive alternative research programs. No other commodity group in the U.S. has funded more research to find an alternative to methyl bromide than the California Strawberry Commission.

Please contact the California Strawberry Commission with any questions about the industry’s use of methyl bromide as a soil fumigant at 831.724.1301.

For more information about methyl bromide, please refer to the following documents and webpages:

• Fumigant Resource Center
• Making Methyl Bromide Rules More Protective
• Managing Methyl Bromide Seasonal Exposure
• United States E.P.A. Methyl Bromide Ozone Page
• MBAO Conferences (International research conference on Methyl Bromide alternatives and emissions reductions)
• United Nations Ozone Secretariat

© 2009 California Strawberry Commission. All Rights Reserved. CSC Disclaimer.