Is Fertilizer a Plant Growth Regulator? EPA wants to know!

The Environmental Protection Agency, EPA, issued a “Draft Guidance for Pesticide Registrations on Plant Growth Regulators label claims, Including Plant Bio Stimulants” within the federal register located here: on March 21, 2019, which was updated on March 28thPublic comment must be submitted on or before May 28, 2019, through the link in Docket #

Our comments from within the industry are extremely important. Here is some information you should know.

The 2018 Farm Bill passed by Congress required USDA to come up with a definition for a “plant bio stimulant” or a PBS. The definition “is considered a substance or micro-organism that, when applied to seeds, plants, or rhizosphere, stimulates natural processes to enhance or benefit nutrient uptake, nutrient efficiency, tolerance to abiotic stress, or crop quality and yield”. The definition does not say that a PBS is a fertilizer nor does it say that it is a pesticide. There currently is no applicable definition of PBS under FIFRA.

The EPA has come up with their own definition of a “plant bio stimulant”.  A PBS is 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 soil in order to improve nutrient and/or water use efficiency by plants.

Now that the EPA has its own definition for a PBS, it is reasoning that the products are physiologically influencing the growth and development of plants in such a way as to be considered a plant growth regulator under FIFRA, thereby triggering it to be included in the regulations for pesticides. Spelled out it looks like this: OVER REACH!

The EPA states in its Label Review Manual published in April, 2014 located here: under Section III, a product is a pesticide if it is “intended” to be a pesticide.  Furthermore, they add that it is a product intended for preventing, destroying, repelling, or mitigating a pest or intended for use as a plant regulator, defoliant or desiccant.  Under the publication, same section, subsection D, it states that “a plant growth regulator, through physiological action, is intended to accelerate or retard growth, or alter plant behavior or the produce of the plant. Examples of plant growth regulator claims include: increased blossom set, stimulation of root or plant growth, prevention of sucker growth, delayed onset of sprouting of harvested root crops, abscission stimulation of fruit crops, stimulates plant growth and fruiting, promotes fruit and seed development, increases stem and stalk strength, and increases fruit size.  Whether a product is considered to be a plant growth regulator depends on whether the plant response or mode of action being claimed would go beyond what would be expected from simple nutrition. The composition of the product may aid in making the determination”.

Simple plant nutrition is not defined and thus it is important for the industry to let the EPA know in their comments that Nitrogen, Phosphorus, Potassium, Sulfur and the micronutrients used for agricultural production are not plant growth regulators and therefore are not pesticides and are not to be included as FIFRA products.  By definition, the terminology can be confusing. What is not confusing is that nutrients used for plant production should not be considered plant growth regulators and certainly should not be considered under the regulations governing pesticides.