Nick Andrews, Oregon State University
Brian Baker, Organic Materials Research Institute
Organic farming relies on a systems approach to crop production and pest management that consists of more than simply substituting natural inputs for ones that are synthetically produced. Organic production practices must maintain or improve the natural resources of an operation, including soil and water quality. Organic farmers must develop a system of cultural, biological, and/or genetic strategies in a comprehensive disease management program, and describe this program in the Organic System Plan, before applying a pesticide as a control measure. However, in some cases, materials for disease management must be applied to control difficult problems such as potato late blight or peach leaf curl. In these cases, how can a farmer determine what materials are allowed for disease management on their certified organic farm?
Allowed and Prohibited Substances
Under the National Organic Program rule, synthetic substances are generally prohibited, with exceptions that appear on the National List. Natural substances are generally allowed, unless they appear as prohibited on the National List. This requirement applies to all substances, not just to active ingredients. Only minimum-risk inert ingredients are permitted in formulations used in organic production. Naturally occurring microorganisms, plant extracts, and mined minerals may also be used to prevent diseases.
When preventive practices and nonsynthetic materials are insufficient to prevent or control diseases, allowed synthetic materials may be used. The conditions requiring such use must be documented in the Organic System Plan (OSP). The OSP should include a clear threshold or decision rule for when a synthetic pesticide is to be applied, and a system to monitor its use. The Accredited Certifying Agent (ACA) needs to approve the OSP before the farm is certified as organic. If a farm uses a pesticide that is not on the OSP for a use already approved by the certifier, that farm may lose its certification.
According to the Organic Farming Research Foundation's organic farmer survey, sulfur and copper are the first and second most-applied disease control materials on organic farms, with 40% and 34% of responding farms reporting their use, respectively. Fixed coppers exempted from the requirement of a pesticide residue tolerance by EPA can be applied as long as they are used in a way that minimizes copper accumulation in the soil. Among those allowed include specific formulations of copper sulfate, copper hydroxide, copper octanoate, copper oxide, and copper oxychloride. Bordeaux mix (copper sulfate combined with hydrated lime) and lime-sulfur are also permitted.
Narrow-range oils used as dormant, suffocating, and summer oils can be used for disease and insect pest management. Hydrogen peroxide and potassium bicarbonate—two familiar substances that are relatively new as fungicides—are also permitted. Growers whose crops are infected with fire blight can use peracetic acid. Antibiotics are no longer permitted for fire blight control. For information on non-antibiotic control of fire blight, see the eOrganic articles Fire Blight Control for Organic Orchards: Moving Beyond Antibiotics and Organic Fire Blight Management in the Western U.S..
There are some materials that are allowed for some applications but not others, so it is important to be sure that a product is permitted for your intended use. Hydrated lime, for example, can be used for disease control but not as a soil amendment. Be sure to always check with your certification body for accepted use of materials.
Some materials often thought of as natural are considered synthetic under the NOP because of the way they are manufactured. For example, sulfur is listed as an allowed synthetic input because much of the sulfur used in agriculture comes from the scrubbers on the smokestacks of petroleum and natural gas refineries. Therefore, sulfur falls under the definition of synthetic due to the chemical reaction occurring in the scrubbers.
Non-active or inert ingredients are classified according to level of toxicological concern. The EPA has changed how it lists inert ingredients, and the NOP has taken over the maintenance of the list of substances used as inert ingredients that the EPA determined to be of minimal concern prior to 2004. To be NOP-compliant, all synthetic inert ingredients in pesticides must either be classified as minimum risk, appear specifically on the National List, or used in passive pheromone dispensers. Inert ingredients do not appear on labels, so verifying compliance with this annotation requires the cooperation of the pesticide registrant.
Brand Name Materials Lists
The NOP established a policy that each Accredited Certifying Agent (ACA, or certifier) is responsible for conducting its own reviews of inputs for agricultural production, such as formulated pesticides and soil amendments. The NOP also allows certifying agents to recognize reviews conducted by other certifying agents and competent third-party reviewers. All ACAs are required to verify, along with their clients, that all materials used by certified organic operations comply with the NOP. In summary, ACAs have three options available to determine whether branded or formulated products comply:
- ACAs can contact the manufacturer to obtain disclosure of the contents of the product and verify that they all comply.
- ACAs may consult with another ACA that has reviewed the information and accept their determination that the material is NOP-compliant.
- ACAs may consult with a reputable third-party source such as the Environmental Protection Agency (EPA) or the Organic Materials Review Institute (OMRI) that reviews materials for compliance with the NOP regulations.
ACAs must document their determinations and verify that the inputs are used according to the standards. ACAs must either have the capacity and expertise to review products or contract with organizations accredited do so. Many ACAs contract with OMRI, a non-profit organization initially established by certifiers specifically for that purpose. The Washington State Department of Agriculture (WSDA) and California Departmet of Food & Agriculture (CDFA) also review products according to the NOP and publish lists of brand-name products that other ACAs use. The OMRI, WSDA, and CDFA lists are available online. These lists are not comprehensive, so there may be other brand name products that can be used. However, in order to be sure that a product complies, the manufacturer must fully disclose all ingredients and manufacturing processes to an ACA or a third party contracted by the ACA. All ingredients must comply with the standards described above. When in doubt about the status of an input, certification applicants and certified producers should check with their certifiers before purchasing or applying the substance, and get the approval in writing.
The OSP is part of the organic certification application form and includes any updates provided to the ACA, who can help by providing sample forms. The OSP is the basis of the recordkeeping system that is reviewed during the certification process. If allowed synthetic inputs are used, it is especially important to describe preventive disease-management strategies in the OSP to demonstrate that these pesticides are only used when preventive methods are insufficient to manage disease.
The NOP requires that all inputs used and planned for use must be included in the OSP, and be reviewed and approved by the ACA before use. When the inspector visits, product labels are sometimes sufficient to demonstrate NOP-compliance of a brand name-product. For example, if using sulfur or a microbial product, the label indicates that the active ingredient is allowed for disease control. If the product is listed with OMRI, WSDA, or CDFA, the label should provide sufficient proof for the inspector to verify that the brand-name product meets the NOP standard. If a product is not listed with OMRI, WSDA, or CDFA, the label will help to verify whether its active ingredients are allowed. However, the farmer or ACA must have a disclosure from the manufacturer that all ingredients, including the inerts, meet NOP requirements. In addition to labels, producers should keep copies of receipts and shipping invoices for all purchased inputs. Producers and ACAs must maintain these records for five years.
Pesticide application records must be maintained, and are reviewed during inspections. They can be kept in whatever form is adapted to the farm, but must be sufficient to demonstrate compliance with the NOP. A record indicating the material(s) used and the date, rate, and location of application is usually sufficient. In the case of copper materials, pesticide application records help to verify that they are applied in a manner that minimizes soil accumulation of copper. See the related article Organic Management of Late Blight of Potato and Tomato with Copper for more information.
One Step at a Time
Before using a new product, check for recent OMRI, WSDA, or CDFA approval of the product. If it isn't listed, follow these steps:
- Evaluate each label ingredient for compliance with the NOP and any annotations in the National List. The OMRI Generic Materials List may also be a helpful guide.
- If the active ingredient is allowed, contact the manufacturer and request all the ingredients in the formula. Make sure all of the ingredients are on the USDA's list of permitted inert ingredients.
- Document that all the annotations, or NOP restrictions associated with use of the material, are met.
Be sure to contact your ACA if you have any doubt about the NOP compliance of a material. If they do not contract with OMRI, WSDA, or CDFA, they may require the information directly from the manufacturer.
National Organic Program Language on Materials
The NOP regulation defines synthetic as, "A substance that is formulated or manufactured by a chemical process or by a process that chemically changes a substance extracted from naturally occurring plant, animal, or mineral sources, except that such term shall not apply to substances created by naturally occurring biological processes."
Section 205.601 lists the synthetic substances allowed for use in organic crop production. The list you see here is abbreviated to paragraphs (i) and (m). Please see the Electronic Code of Federal Regulations for a complete list. In accordance with restrictions specified in this section, the following synthetic substances may be used in organic crop production:
(i) As plant disease control:
- Aqueous potassium silicate (CAS #-1312-76-1)—the silica, used in the manufacture of potassium silicate, must be sourced from naturally occurring sand.
- Coppers, fixed—copper hydroxide, copper oxide, copper oxychloride, includes products exempted from EPA tolerance, provided that copper-based materials must be used in a manner that minimizes accumulation in the soil and shall not be used as herbicides.
- Copper sulfate—Substance must be used in a manner that minimizes accumulation of copper in the soil.
- Hydrated lime.
- Hydrogen peroxide.
- Lime sulfur.
- Oils, horticultural, narrow-range oils as dormant, suffocating, and summer oils.
- Peracetic acid—for use to control fire blight bacteria. Also permitted in hydrogen peroxide formulations as allowed in §205.601(i) at concentration of no more than 6% as indicated on the pesticide product label.
- Potassium bicarbonate.
- Elemental sulfur.
- Polyoxin D zinc salt.
(m) As synthetic inert ingredients as classified by the Environmental Protection Agency (EPA), for use with nonsynthetic substances or synthetic substances listed in this section and used as an active pesticide ingredient in accordance with any limitations on the use of such substances:
- EPA List 4—Inerts of Minimal Concern.
- EPA List 3—Inerts of unknown toxicity—for use only in passive pheromone dispensers.
Section 205.602 lists nonsynthetic substances that are prohibited for use in organic crop production. The following nonsynthetic substances may not be used in organic crop production:
- Ash from manure burning.
- Calcium chloride—brine process is natural and prohibited for use except as a foliar spray to treat a physiological disorder associated with calcium uptake.
- Lead salts.
- Potassium chloride—unless derived from a mined source and applied in a manner that minimizes chloride accumulation in the soil.
- Rotenone (CAS # 83-79-4).
- Sodium fluoaluminate (mined).
- Sodium nitrate—unless use is restricted to no more than 20% of the crop's total nitrogen requirement.
- Tobacco dust (nicotine sulfate).
References and Citations
- Agricultural Marketing Service National Organic Program [Online]. Available at: http://www.ams.usda.gov/nop (verified 10 March 2010).
- Agricultural Marketing Service Regulations [Online]. Available at: http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&sid=3f34f4c22f9aa8e6d9864cc2683cea02&tpl=/ecfrbrowse/Title07/7cfr205_main_02.tpl (verified 31 August 2012).
- California Department of Food & Agriculture, Organic Input Material Program [Online]. Available at: https://www.cdfa.ca.gov/is/ffldrs/fertilizer_OIM.html (verified 8 Mar 2019).
- National Organic Program—Submission of Petitions of Substances for Inclusion on or Removal From the National List of Substances Allowed and Prohibited in Organic Production and Handling [Online]. Agricultural Marketing Service United States Department of Agriculture. Washington, D.C. Available at: https://www.ams.usda.gov/sites/default/files/media/1-MCP%20Petition.pdf (verified 1 April 2021).
- OFRF Fourth National Organic Farmers' Survey: Sustaining Organic Farms in a Changing Organic Marketplace. Waltz, E. 2004. Organic Farming Research Foundation. Santa Cruz, California. Available at: http://www.ofrf.org/sites/ofrf.org/files/docs/pdf/4thsurvey_results.pdf (verified 10 March 2010).
- Organic Materials Review Institute [Online]. Available at: http://www.omri.org/ (verified 10 March 2010).
- Organic Production and Handling Standards [Online]. 2011. Agricultural Marketing Service United States Department of Agriculture. Washington, D.C. Available at: https://www.ams.usda.gov/sites/default/files/media/Organic%20Production-Handling%20Standards.pdf (verified 8 March 2019).
- Washington State Department of Agriculture Organic Program [Online]. Washington State Department of Agriculture. Available at: http://agr.wa.gov/FoodAnimal/Organic/ (verified 8 March 2019).