Pesticide law defines a “pesticide” (with certain minor exceptions) as:

• Any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest.
• Any substance or mixture of substances intended for use as a plant regulator, defoliant, or desiccant.
• Any nitrogen stabilizer.

See the definition in Section 2(u) of the Federal Insecticide, Fungicide, and Rodenticide Act. (Also referred to as U.S. Code Title 7, Chapter 6, Subchapter II, Section 136 - Definitions)

Read more about ingredients used in pesticide products.

EPA’s regulations (see 40 CFR 152.6 –152.15) provide additional clarification. Thus the intent of the product is important in determining if a specific product is a pesticide. The intent of the product can be determined by examining the:

• claims on the label and advertising;
• composition;
• use; and
• mode of action of the product as distributed or sold.

A product is likely to be a pesticide if the labeling or advertising:

• Makes a claim to prevent, kill, destroy, mitigate, remove, repel or any other similar action against any pest.
• Indirectly states or implies an action against a pest.
• Draws a comparison to a pesticide.
• Pictures a pest on the label.

Except in limited circumstances, any substance falling within this definition of a pesticide must be registered by the EPA before it can be legally sold or distributed in the United States. One such exception to the registration requirement is for those pesticides that the Administrator, under section 25(b) of FIFRA, has determined “to be of a character which is unnecessary to be subject to this Act,” and that have been exempted from the requirements of FIFRA by regulation.