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Ohio State University Extension


Biopesticide Controls of Plant Diseases: Resources and Products for Organic Farmers in Ohio

Agriculture and Natural Resources
Chunxue Cao, Sunjeong Park, and Brian B. McSpadden Gardener, Department of Plant Pathology, The Ohio State University

Different agricultural practices, such as the use of crop rotation, cover crops, disease resistant varieties, and good seed bed preparation have been applied to control pests and diseases. However, such practices are not always sufficient protection from crop losses. Because of this, many certified organic growers turn to biopesticides to insure and/or enhance their abilities to grow and market high-quality produce. Approved organic products for plant disease control include many EPA-registered biopesticides. Such products have been developed to control numerous plant diseases and to provide useful tools for growers to decrease the incidence and/or severity of plant diseases.

Biopesticides that can be used by organic growers can be classified as either microbial or biochemical, based on the active ingredient. Microbial pesticides include live organisms (e.g., beneficial bacteria, fungi, nematodes, and viruses) and/or their fermentation products as the active ingredient. Biochemical pesticides include plant extracts, pheromones, plant hormones, natural plant-derived regulators, clay, potassium bicarbonate, and enzymes as the active ingredient. In this fact sheet, only commercially available microbial and biochemical biopesticides are discussed.

Biopesticides are used primarily as preventative measures, so they may not perform as quickly as some synthetic chemical pesticides. However, biopesticides are generally less toxic to the user and are non-target organisms, making them desirable and sustainable tools for disease management. While their use is not overly complicated, the application of some biopesticides may require a high level of understanding and knowledge of the diseases and pathogens that they are designed to control. As with any disease management program, proper timing and application are essential to ensuring efficacy.

To help organic farmers choose an appropriate biopesticide for different plant diseases, we have provided a synthesis of numerous independent field tests for commercially available microbial biopesticides (Table 1) and biochemical biopesticides (Table 2). Both lists include only products certified for use in organic agriculture by the Organic Materials Review Institute (OMRI). The lists contain the trade name, target disease, crop, and efficacy evaluation results of each product as published in the Plant Disease Management Reports and Biological Control Tests Database between 2000 and 2009. An efficacy rating based on these reports was established based on the comparison between untreated and biopesticide-treated plants in one or more reports. The ratings are categorized as follows: “+”indicates that control of disease or increase in yields was observed, “±” indicates that in some cases there was some positive responses while in other cases there was no response, “o” indicates that neither positive nor negative effect was observed by the use of the product, and “*” indicates that no data are available.

Table 1. Microbial Biopesticides for the Control of Plant Pathogens

Table displaying microbial pesticides for the control of plant pathogens 

Click to download PDF

Table 2. Biochemical Biopesticides for the Control of Plant Pathogens

Table displaying microbial biopesticides for the control of plant pathogesns.

Click to download PDF

Additional Resources

  • American Phytopathology Society (APSnet). APS is a global community of researchers that provides valuable information about plant health (
  • IR-4 Project. This federally-funded effort supports biopesticide development and registration efforts. The IR-4 Project has developed a database for biopesticide labels and products in the United States (
  • Ohio Department of Agriculture (ODA). ODA is the state agency that provides regulatory protection to producers, agribusinesses, and the consuming public in Ohio (
  • Organic Food and Farming Education and Research Program (OFFER). OFFER is a group of researchers from The Ohio State University that offers research and education for organic production, processing, and marketing (
  • Organic Review Materials Institute (OMRI). OMRI is an institution that evaluates and certifies products for use in certified organic productions, handling, and processing (
  • United States Department of Agriculture (USDA)/National Organic Program and Economic Research Service. The USDA works to set organic farming production standards ( and to collect information about organic agriculture (
  • United States Environmental Protection Agency/Biopesticides. This subdivision of the EPA is responsible for regulating and registering biopesticides in the United States (


Funding to support the development of these materials was provided by the USDA’s Organic Agriculture Research and Extension Initiative Grant, 2009-51300-05512.


Originally posted Jun 25, 2010.