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Regulatory Entomology


In the United States, the manufacture, sale, and use of pesticides is heavily regulated by state and federal governments.  Federal jurisdiction over pesticides began in 1906 with the Pure Food and Drug Act and the Federal Insecticide Act of 1910.  These rather loosely written laws were superceded by the Food, Drug, and Cosmetics Act of 1938 that gave the Food and Drug Administration (FDA) a mandate to insure the safety of all commercial products intended for human consumption.  More comprehensive legislation, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was passed in 1947 with regulatory powers split between the FDA and the United States Department of Agriculture (USDA).  In 1972, the Federal Environmental Pesticide Control Act amended FIFRA and transferred oversight of all pesticide regulation to the newly formed Environmental Protection Agency (EPA).  Additional changes and amendments were added under the Food Quality Protection Act (FQPA) of 1996.  Today there are at least 14 separate pieces of federal legislation that govern the manufacture, registration, distribution, use, consumption, and disposal of pesticides.

The major provisions of FIFRA (as amended) include:
  • Specifies registration procedures for all pesticide manufacturers
  • Prohibits all use of pesticides not explicitly stated on the label
  • Establishes a special category for “restricted use” pesticides
  • Requires state certification for all users of “restricted use” pesticides
  • Allows for emergency exemptions and special local needs
  • Establishes inspection procedures to ensure compliance

Insecticide Registration

In order to legally sell a pesticide in the United States, a manufacturer must first obtain a registration for the active ingredient(s).  The registration process involves a careful review of the environmental and health impacts of a pesticide.  This “risk assessment” is a four-step process:

  1. Hazard Identification – acute and chronic toxicity studies More about Toxicity are conducted on animal subjects to determine the potential for adverse effects such as irritation to eyes and skin, occurrence of cancer or birth defects, respiratory problems, etc.
  2. Dose-response Assessment – the dosage levels at which adverse effects occur in surrogate test animals (e.g. rats, mice, rabbits, etc.) are used to calculate an equivalent dose for humans.
  3. Exposure Assessment – people may come into contact with pesticides on the food they eat, in the water they drink, on the job as a pest control applicator or agricultural worker, and around the home or garden where chemicals are used as insect repellents and to control insects, weeds, mold, mildew, bacteria, etc.
  4. Risk Characterization – the risk to human health from pesticides depends on both toxicity of the chemical and the likelihood of exposure.  Simply put:


A chemical company must submit a package to the EPA containing all of the required data from toxicity studies, residue analysis, exposure assessment, and long-term scrutiny of the chemical and its breakdown products (environmental fate).  As part of its review, the EPA groups each pesticide into one of the following categories based on estimates of the toxicity and risk profile:

LD50 Range
Restricted Use
<50 mg/kg
50-500 mg/kg
500-5000 mg/kg
>5000 mg/kg

All category I and II pesticides (as well as some category III pesticides) are designated as “restricted use” chemicals.  These compounds may only be sold to (and used by) people who have been “certified” by an agency of their state government and received a pesticide applicator’s license.  This certification process usually involves special training and a written examination.  Only “general use” chemicals may be purchased by the public without a pesticide applicator’s license.

The EPA regulates the safety of our food supply by limiting the residual amount of pesticide (residue) that legally may be present on each agricultural product at harvest.  This maximum limit, called a tolerance, is established through the above process of risk assessment.  Using the dose-response curves found during animal studies of acute and chronic exposure to a pesticide, the EPA determines a level of exposure that should have no observable effect in humans (NOEL = No Observable Effect Level).  To insure a significant margin of safety, the NOEL value is further divided by an “uncertainty factor” (usually about 100) to give a Reference Dose (RfD).  The uncertainty factor is usually higher for pesticides that are more hazardous or may be applied to foods that are consumed in greater quantities by children, older adults, or other “at-risk” populations.  For each agricultural product that will be treated with the insecticide, EPA sets a tolerance (well below the reference dose) based on an ongoing “market basket survey” by the FDA that estimates the types and amounts of foods consumed in the typical American diet.  This process insures that no matter what combination of treated produce is consumed, the intake of a pesticide will never exceed its reference dose.

Once a tolerance has been issued, the chemical company must submit a label for approval both by the EPA and by state governments where the pesticide will be sold.  The label specifies the commodities on which the pesticide may be used and limits the application rate so residues will not exceed the tolerance.

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Labels and Rates
Chemical companies must spend millions of dollars in research and development costs to shepherd each new pesticide through the regulatory jungle.  In order for companies to make any money, they must recoup their expenses and return a profit to shareholders before the chemical’s patent expires in 17 years.  As a result, there is no incentive to develop products for minor crops or niche markets because the financial return is just too small.  If a pesticide cannot be used on a major crop like corn, wheat, soybeans, or cotton, it will probably never become registered.  Two legislative provisions help to counteract this problem:

  1. Under authority of Section 24(c) of the Federal Insecticide, Fungicide, and Rodenticide Act, state governments may register additional uses of a federally registered pesticide to meet a “special local need”.  Such state registrations cut the time, expense, and red tape needed to get a pesticide approved for a regional crop or a local pest problem.  One caveat, however, is that the pesticide must already have a federal label for some other use.
  2. Interregional Research Project No. 4 (the IR-4 Project) is a “minor use pesticides” program.  It is a partnership, established in 1963, between the USDA and the land grant university system to help farmers, agriculture scientists, and Extension personnel conduct research and obtain tolerances for specific pesticide uses on specialty food crops (such as fruits, vegetables, and herbs) and other minor uses (such as floral, nursery, or turf crops).

Although each “minor crop” is only a small percentage of U.S. agriculture, as a group they represent about 40% of the agricultural acreage and more than $40 billion in annual farm revenue.  That’s no small potatoes!