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A report from  Deborah Carter and Dr. Mike Willett, Northwest Horticultural Council

Pacific Northwest growers have done a great job responding to complex international regulations on pesticide residues. In support of these efforts, the Northwest Horticultural Council provides a view behind the complexity and a peek into the future.

In the United States, a legal pesticide residue on a crop is termed a tolerance.

How MRLs are set

(Source: Bayer CropScience)

In the rest of the world, this tolerance is referred to as a maximum residue level or limit, also referred to as MRL. Maximum residue limits are established for all fresh and processed foods based on risk assessments done by the pesticide regulatory agency in each country (see “How MRLs are set” chart).

In the United States, tolerances are established using the result of residue studies done at the maximum label rate and number of applications, with treatments timed as close to harvest as the label allows.

However, in practice, pesticides are usually applied in moderation, which often results in residues significantly lower than the tolerance.

Other countries set MRLs based on how the product is likely to be used, which may result in an MRL lower than the U.S. tolerance. However, differences in allowable residues don’t always result in violations because growers’ pest management programs, which are aimed at efficacious but minimal use, almost always result in residues lower than the tolerance.

This understanding should be confirmed for critical chemicals on a crop-by-crop basis. Studies done by the Washington Tree Fruit Research Commission and posted on its website (http://www.treefruitresearch.com) support this understanding.

Also, registrants can provide information about likely residues for products that are new to the market, helping producers decide how best to use new materials that may not have MRLs in export markets.

International standards

The Codex Committee on Pesticide Residues, an international standards setting body, is seeking ways to accelerate its response cycle in setting new MRLs that provide a benchmark that countries with limited regulatory infrastructures can adopt as a standard.

Fewer residue trials for specialty crops and a new way of making comparisons among residue trials are being employed to streamline the Codex MRL establishment process.

However, Codex remains somewhat cumbersome because member nations that do the work for Codex’s Joint Meeting on Pesticide Residues have limited resources and some countries’ representatives are resistant to initiatives designed to speed MRL establishment. Also, it is a large international regulatory body with inherent inertia.

Around the world, the processes used to set MRLs are continually evolving and at times becoming more restrictive. The European Union continues to institute stricter criteria to register crop protection chemicals.

European retailers have joined the fray in creating additional barriers to trade by establishing secondary standards for their suppliers that are even more restrictive than EU regulations.

Recently, a number of Asian countries have decided to set their own “positive MRL list,” meaning a list set specifically by the government of that country (as opposed to deferring to standards set by outside entities), which may or may not include the most important crop protection chemicals used in Pacific Northwest orchards.

For example, in the next two years, we will see Hong Kong and South Korea establish their own positive lists. We are concerned that the outcome of the Korean effort may be challenging.

Information is critical

Comprehensive, up-to-date information on foreign market MRLs is critical to avoiding trade problems. Credit should be given to the efforts of Pacific Northwest growers, packers, shippers, and marketers who have done a remarkable job in meeting MRL standards around the world.

These efforts have been aided by the U.S. Department of Agriculture’s Foreign Agricultural Service and the U.S. Environmental Protection Agency. Both these organizations have placed a high priority on making foreign MRL requirements available to exporting industries (www.mrldatabase.com).

The Northwest Horticultural Council makes this and other information available at www.nwhort.org. For our industry’s top markets, our information is updated continuously on a market-by-market basis and fully reviewed two to three times each year.

The Minor Crop Farmer Alliance, an alliance of over 30 specialty crop producer organizations, plays a key role in helping to make comprehensive MRL information available.

It works closely with the FAS and EPA to support growers’ MRL needs; and directly engages foreign governments on MRLs and trade issues. Northwest Horticultural Council staff play key roles in the work of the alliance. •