Can I Use this Product for Disease Management on my Organic Farm?

Organic Agriculture June 11, 2015 Print Friendly and PDF

eOrganic authors:

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 her or his 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 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 non-synthetic 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 certifer, that farm may lose its certification.

According to the Organic Farming Research Foundation 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 that are 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. Finally, growers whose crops are infected with fire blight can use peracetic acid, streptomycin (in apples and pears only), and tetracycline (oxytetracycline calcium complex). Antibiotic resistance is a concern, so growers with fireblight are advised to prune and rotate antibiotics with other tools, such as copper.

In some cases materials can be used for some uses but not others, so make sure that the product is permitted for the use you intend. Hydrated lime can be used for disease control, but not as a soil amendment. The antibiotics streptomycin and tetracycline are allowed for fire blight control only. At present, peracetic acid cannot be used to treat seed potatoes.

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 the level of toxicological concern. 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 EPA determined to be of minimal concern prior to 2004. To be NOP compliant, all synthetic inert ingredients in pesticides must be classified as minimum risk, appear specifically on the National List or are 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, 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 as described in the Verification of Materials policy. All ACAs are required to verify, along with their clients, that all materials used by certified organic operations comply with the NOP. To paraphrase, ACAs have three options available to determine whether branded or formulated products comply:

  1. ACAs can contact the manufacturer to obtain disclosure of the contents of the product and verify that they all comply;
  2. ACAs may consult with another ACA that has reviewed the information and accept their determination that the material is NOP compliant; or
  3. 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 initially established by certifiers specifically for that purpose. The Washington State Department of Agriculture (WSDA) also reviews products according to the NOP and publishes a list of brand name products that other ACAs use. The OMRI and WSDA lists are both 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.

Record Keeping Requirements

The OSP is part of the application form and includes any updates provided to the ACA, who can help by providing sample forms. The OSP is the basis of the record keeping 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 in order to help 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 OMRI or WSDA listed, the label should be sufficient proof for the inspector to verify that the brand name product meets the NOP standard. If a product is not OMRI or WSDA listed, the label will help to verify whether 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 purchase receipts and shipping invoices for all purchased inputs. Producers and ACAs must maintain these records for five years.

Pesticide application records must be maintained. These are also reviewed during inspections. They can be kept in whatever form is adapted to the farm, but they must be sufficient to demonstrate compliance with the NOP. Normally a record of the material used and the date, rate, and location of application is sufficient. In the case of copper materials, pesticide application records can help verify whether copper products are applied in a manner to 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 or WSDA approval of the product. If it isn’t listed, follow these steps:

  1. 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.
  2. If the active 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.
  3. 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 or WSDA, 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:

  1.  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.
  2. Copper sulfate - Substance must be used in a manner that minimizes accumulation of copper in the soil.
  3. Hydrated lime
  4. Hydrogen peroxide
  5. Lime sulfur
  6. Oils, horticultural, narrow range oils as dormant, suffocating, and summer oils.
  7. Peracetic acid—for use to control fire blight bacteria.
  8. Potassium bicarbonate
  9. Elemental sulfur
  10. Streptomycin, for fire blight control in apples and pears only
  11. Tetracycline (oxytetracycline calcium complex), for fire blight control only

(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.

  1. EPA List 4 - Inerts of Minimal Concern
  2. EPA List 3 – Inerts of Unkown 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:

  1. Ash from manure burning
  2. Arsenic
  3. Calcium chloride, brine process is natural and prohibited for use except as a foliar spray to treat a physiological disorder associated with calcium uptake.
  4. Lead salts
  5. Potassium chloride—unless derived from a mined source and applied in a manner that minimizes chloride accumulation in the soil.
  6. Sodium fluoaluminate (mined)
  7. Sodium nitrate—unless use is restricted to no more than 20% of the crop’s total nitrogen requirement.
  8. Strychnine
  9. Tobacco dust (nicotine sulfate)
    (j-z) [Reserved]

References and Citations


This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.