Biorational and Organic Pesticides

All pesticides are toxic, but they vary in their toxicity to people and non-target organisms, and in their potential ecological impact. Integrated pest management emphasizes using cultural and biological controls, and when pesticides are necessary, selecting materials with comparatively low toxicity. The term ‘biorational’ is used in this guide to mean pest control materials that are relatively non-toxic to people with few environmental side effects. Biorational pesticides generally have less impact on non-target species, including bees and other beneficial insects, because they tend to degrade rapidly in the environment; in addition, biorational insecticides are often effective for specific target pest groups or life stages. 

There are no official criteria that define the term ‘biorational’. The tables of biorational and biological control products in the Disease and Insect Management sections of this Guide (Tables 26, 27, 29, & 30) are intended to help you select products that are compatible with an integrated pest management approach. The tables include active ingredients (AIs) that are 1) listed by EPA as biopesticides, 2) listed by the Organic Materials Review Institute (OMRI) for use in organic production, and/or 3) general use materials that have relatively low toxicity profiles. The tables also include biocontrol organisms that may be released or applied to crops, or may already be established on New England farms. Not all biopesticides or OMRI-listed products are included. No listed products are federally restricted-use. Most have high (>2000) dermal and oral LD₅₀ values (and therefore lower toxicity) and their labels carry the EPA signal word “Caution” or are exempt from requiring a signal word. Note that some formulations of pesticides that contain AIs approved for use in organic production, such as copper sulfate or copper hydroxide, may have low dermal and oral LD₅₀ values and carry the EPA signal word “Warning” or “Danger” on their labels. 

Biopesticides

Biopesticides, as defined by EPA, are certain types of pesticides derived from natural materials such as animals, plants, bacteria, and certain minerals. The EPA maintains a comprehensive list of all registered biopesticide active ingredients; as of February 2026, there are 454 registered biopesticide AIs. EPA generally requires less data to register a biopesticide than to register a conventional pesticide, thus the registration process is faster.

Biopesticides fall into three major classes:

Biochemical pesticides, which are naturally occurring substances that control pests by non-toxic mechanisms, such as sex pheromones that interfere with mating and scented plant extracts that attract insect pests to traps. These include botanicals—plant-derived materials such as pyrethrin, azadiractin, and extracts of plants such as Chenopodium ambrosioides and Swinglea glutinosa, as well as plant-derived oils such as neem, canola, and sesame oils. Botanicals are generally short-lived in the environment, as they are broken down rapidly in the presence of light and air. Products generally have low mammalian toxicity and a broad spectrum of activity. Many botanicals are considered minimum risk pesticides and are exempt from registration by EPA.

Microbial pesticides are formulated from living microorganisms (bacteria, fungi, viruses, or protozoa) and/or their by-products. Microbial insecticides tend to be selective, so specific pests may be controlled with little or no effect on non-target organisms, while most microbial disease control products have a wider spectrum of activity. Microbial insecticides may be derived from bacteria (e.g. Bacillus thuringiensis, spinetoram and spinosad, Chromobacterium subtsugae), virus (e.g. nuclear polyhedrosis virus of corn earworm) or fungi (e.g. Beauvaria bassiana). Microbial disease control products are living organisms, including beneficial fungi and bacteria. Examples of microbial disease control organisms are the fungus Trichoderma harzianum and the bacterium Bacillus subtilis. While these active ingredients are generally approved for organic production (OMRI-listed) because of their natural origin, certain formulated products are prohibited because the inert ingredients or procedures used in making the product are prohibited.

Plant-Incorporated Protectants (PIPs), in which pesticidal substances are produced by crop plants as a result of genetic material being added to the plant (e.g., Bt corn, which contains an insecticidal protein that kills lepidopteran pests). With PIPs, the toxin and its genetic material, but not the plant itself, are regulated by EPA.

Other Types of Biorational Pesticides

Minerals. Some pesticides are made from minerals. They are mined from the earth and minimally processed, and are generally allowed in organic production. Examples include kaolin clay, sulfur, iron phosphate, and mineral oil. Many minerals are considered minimum risk pesticides and are exempt from registration by EPA, though copper-based products are a notable exception. 

Synthetics. Minerals and other natural materials that are heated, chemically reacted, or mixed with surfactants may be considered synthetics. Synthetics also include some insect growth regulators (IGR), which interrupt or inhibit the life cycle of a pest. They may also work by strengthening plant defenses. While National Organic Program standards generally prohibit the use of synthetic pesticides, some synthetics, including horticultural oils and insecticidal soaps may be allowed.

Pesticides in Organic Production 

The USDA regulates the production of organic products through the National Organic Program (NOP). The regulations describe organic agriculture as the application of a set of cultural, biological, and mechanical practices that support the cycling of on-farm resources, promote ecological balance, and conserve biodiversity. While it is a common misconception that fruits and vegetables that are certified under the NOP as ‘organic’ were produced without the use of pesticides, there are many pesticide products that are allowed and commonly used in organic production. The NOP standards allow application of biological, botanical, or mineral inputs when cultural practices are insufficient to prevent or control crop pests, weeds, and diseases. Most of these are non-synthetic and/or minimally processed. 

Not all biopesticides are labeled for use in certified organic agriculture. The grower, in collaboration with their certifying body, is responsible for determining whether materials are allowed under organic standards. The Organic Materials Review Institute (OMRI) is recognized by the NOP as an organic material review organization. It lists products it finds suitable for certified organic production. In some cases, OMRI notes that certain formulations of a product are permitted and others are not. The list of substances approved by OMRI is subject to change.

Be sure to check with your certifier in advance to be certain that the materials and practices you plan to use are approved by your certifier, and that you understand any restrictions on use. See the Organic Certification section of this guide for more information on the NOP standards and how to find an organic certifier in New England. For the most up-to-date OMRI list, visit the OMRI website at: www.omri.org. When mentioned in tables or in crop chapters, this guide designates approved organic materials with a superscript OG (^OG), which means they were "OMRI-listed" at the time of review (June 2026).

All OMRI-listed pesticides should be used in accordance with the same safety standards as other pesticides with regard to handling, mixing, storage, and application, as described in the following sections.