Efforts to chip away at methyl bromide use on agriculture exports could have a serious impact on trade.

At a workshop in Tulare, California commodity group representatives, researchers and regulators looked at quarantine pre-shipment use of methyl bromide and actions taken by Montreal Protocol subcommittees to limit its use.

“QPS (Quality Pre-Shipment) uses are in jeopardy,” said Jim Cranney, California Citrus Quality Council. “Some countries feel methyl bromide should not be out there.”

QPS is one of the uses still allowed for methyl bromide, a fumigant being phased out under an international treaty that calls for phaseout of the ozone depleting fumigant.

Workshop speaker Jim Wells of Environmental Solutions Group LLC, said in 1992, (that) Montreal Protocol committee members recognized some methyl bromide use was necessary to allow for trade. In the absence of an effective alternative to the fumigant, QPS uses were allowed.

Citrus shipments from California to Korea, for instance, must be treated with methyl bromide to prevent the spread of red scale. Loss of that market could cost the industry $80 million annually, Cranney said. California floral and strawberry industries also depend on QPS uses to move products to markets. Research into methyl bromide alternatives for QPS use is ongoing, but new products still must go through a regulatory process, Cranney pointed out. At a fall 2009 QPS workshop in Egypt, Wells said there were discussions about changing some of the parameters for QPS use, including use targeting exotic pests rather than endemic ones.

Critical use of methyl bromide is also eroding. The U.S. deciduous nursery and rose nursery 2012 critical use of methyl bromide was cut 80 percent, and strawberry nursery use was cut 20 percent.

“The timing is terrible because there are not new registered alternatives or facts to support the cuts,” said Wells. “This sends the wrong signal that there are available alternatives.” (Subsequent to the workshop, California Department of Pesticide Regulation registered methyl iodide (Midas) as a methyl bromide alternative.)

Ken Vick, with the USDA’s Agriculture Research Service, said even though alternatives to methyl bromide are available, they are primarily for niche markets and will not work across the board for all commodities that must be fumigated. The year 2015 is important because that is when phaseout of non-QPS use occurs. Some countries may try to move more uses into the QPS category, Vick said.

New, exotic pests are another factor. As control challenges grow and options dwindle, use of alternatives has to be more flexible, Vick said.

The No. 1 fresh product requiring fumigation for U.S. export in 2009 was strawberries, said Mike Guidicipietro, USDA Animal Plant and Health Inspection Service. In the face of new, exotic pests and diseases, the service has moved from opening new markets to working at retaining current markets. The ability to use methyl bromide pre-shipment is necessary to keep markets for U.S. farm produce, he said.

The ability to use methyl bromide to ensure a clean shipment is important because it works, Guidicipietro said. Irradiation is becoming more important as an alternative, especially in southeast Asia and Mexico. The process, however, does not kill pests — it sterilizes them. A panel of researchers discussed progress on possible alternatives to methyl bromide as well as challenges they pose for trade.

Those alternatives included ethyl formate, radio frequency energy and surfactants.

Ethyl formate, a plant-based product sold as Vapormate, has been used in the past on dried fruit, but U.S. registration lapsed in the 1980s. Beth Mitcham, UC Davis, said testing at the university showed it was promising, but not all export products would tolerate it.

Radio frequency energy, a process that is being tried on in-shell nuts to control insects and pathogens, is effective, but also very capital intensive, Mitcham said.