The past decade has seen explosive growth in the market for plant biostimulant products, with estimates of a global market approaching $20 billion by 2025. Nonetheless, these plant biostimulants currently occupy a regulatory gray area in the United States. On March 27, 2019, the United States Environmental Protection Agency released its long-awaited draft guidance on plant biostimulants. EPA is accepting comments on the draft rule, which we summarize below, for sixty days.

So what is a plant biostimulant? Until the 2018 Farm Bill was passed in December of 2018, there was no applicable definition in the United States. In the Farm Bill, Congress directed USDA to conduct a study and make recommendations regarding plant biostimulants, defining that term as “a substance or micro-organism that, when applied to seeds, plants or the rhizosphere, stimulates natural processes to enhance of benefit nutrient uptake, nutrient efficiency, tolerance to abiotic stress, or crop quality and yield.”

A plant biostimulant could be regulated in one of two ways, depending on the active components of the product and the claims made for the product. First, a plant biostimulant could be considered a “plant regulator” (also known as plant growth regulator, or PGR) under the Federal Insecticide, Fungicide and Rodenticide Act (“FIFRA”), meaning it would be regulated by both EPA and the states under pesticides laws authority. If the plant biostimulant was not captured by FIFRA, then state departments of agriculture could regulate the product pursuant to their authority to regulate fertilizers, plant and soil amendments, and other products not regulated by FIFRA (and even then, it is not always clear into which category a plant biostimulant fits).

Not surprisingly, the distinction between a “plant biostimulant” and a “plant regulator” under FIFRA is often unclear. In an attempt to help enable industry and regulators to appropriately classify plant biostimulants, EPA published its “Draft Guidance for Plant Regulator Label Claims, Including Plant Biostimulants.”

Initially, the Draft Guidance notes that it is not bound by the Farm Bill definition of plant biostimulant, and adopts its own definition:

a naturally-occurring substance or microbe that is used either by itself or in combination with other naturally-occurring substances or microbes for the purpose of stimulating natural processes in plants or in the soil in order to, among other things, improve nutrient and/or water use efficiency by plants, help plants tolerate abiotic stress, or improve the physical, chemical, and/or biological characteristics of the soil as a medium for plant growth.

There are key differences between the Farm Bill definition and EPA’s definition, for instance, whether the product needs to be “a substance or micro-organism” (Farm Bill) vs. “a naturally-occurring substance or microbe” (Draft Guidance). EPA has specifically asked for comment on whether it should formally define “plant biostimulant” through a rulemaking procedure.

The Draft Guidance then recognizes the statutory and regulatory basis for its authority over plant regulators, including whether plant regulator claims are made or whether substances known to be plant regulators are included in the product. A plant regulator claim is essentially a claim that the product, through physiological action on the plant, accelerates or retards the rate of growth or rate of maturation, or otherwise alters the behavior of plants or the produce thereof.

The Draft Guidance presents several non-exclusive lists of claims that are considered non-plant regulator claims and claims that are considered plant regulator claims. Although there are too many to list here, the fundamental distinction is whether the product causes acceleration, retardation or modification of plant or produce growth, or whether the product merely improves conditions to aid in plant growth and nutrition. In other words, does the product physically change the plant or does it just help a plant realize its full potential? The former is a plant regulator while the latter is not.

Marketing claims are not the end of the story, though. The Draft Guidance also includes a list of active ingredients that are associated with plant regulator products, including cytokinins, gibberellins, harpin proteins, and seaweed extracts. Although the presence of an ingredient on this list may not always mean the product is by definition a plant regulator, it is at a minimum strong evidence of the same.

Determining whether a plant biostimulant product is subject to FIFRA (and thus regulated by EPA) is very important. Products regulated by FIFRA require significant amounts of data that must be submitted to EPA for a review and registration process, and EPA regulates the manufacturing, packaging, labeling, sale and distribution process. Penalties for failure to comply with FIFRA can include fines of nearly $20,000 per violation, which can accumulate quickly when a product is in mass distribution. EPA also has a recent history of enforcing against companies selling unregistered plant regulators. Thus, EPA’s guidance on plant biostimulants is crucial to understanding regulatory risks associated with certain product registration and marketing pathways. Now is the time to provide input to EPA on this Draft Guidance.