Stonyfield Organic

Pesticides 101

Learn About Pesticides, Herbicides and Insecticides

what is a pesticide?

A pesticide is any substance used to kill or control insects, weeds, fungi, rodents, bacteria, or other unwanted organisms. The term pesticide also applies to herbicides, fungicides, and various other substances used to control pests.

Herbicides are, by far, the most commonly applied pesticide followed by insecticides, fungicides, and rodenticides.

are pesticides used in organic land management?

Non-organic farms spray toxic persistent pesticides and herbicides to keep pests at bay, and many of these chemicals are proving to be harmful to pollinators and other wildlife, as well as to human health. They break down very slowly, remaining in our soil, water and air. Some can continue to cause damage for decades after they are first used.

Organic practices strictly forbid the use of toxic persistent pesticides. Organic farmers rely on techniques that promote ecological balance on the farm, such as cover cropping, crop rotations, planting buffers and hedgerows, and building soil health, to keep pests and diseases in check. Organic farmers can only use approved pesticides as part of an organic ecological systems approach. They are limited to a small number of pesticides that have been reviewed by the National Organic Standards Board and been found to have little to no risk to human health or the environment. Conventional farmers have access to roughly 900 different synthetic pesticides, whereas organic farmers are permitted to use 25. Organic farmers are also allowed to use naturally occurring (non-synthetic) pesticides, but again only if these materials are confirmed to be low-risk for human health or the environment.

Toxic persistent pesticides are not used in any of the StonyFIELDS Initiative Fields.

types of pesticides


for weed control are the most widely used pesticides nationwide. While the mix of weeds vary across the country, spraying herbicides remains, in most regions, the “go to” response for when weeds need managing.


are applied to kill a variety of bugs and grubs.


are periodically used, especially in humid regions, to control fungal pathogens, or other pathogens.

Across the U.S., herbicide use and risks are rising the fastest, as a result of the spread of weeds now resistant to several, if not most, herbicides registered for their control.

about herbicides

Which herbicides are most commonly applied on playing ground fields?

• Glyphosate
• 2,4-D
• Dicamba

About Herbicides

All herbicide products contain one or more active ingredient, plus several so-called “inert ingredients.” Read the EPA overview of inert ingredients here.

Risks can be caused solely or largely by an herbicide’s active ingredient – the chemical in the formulated, herbicide product that delivers the weed-control punch.  However, as the EPA clearly states on its website, “inert does not mean non-toxic. These inert ingredients span a vast array of chemicals, and are often present at equal or higher concentrations than the active ingredient in an off-the-shelf herbicide. By law, manufacturers are not required to identify what these ‘inert ingredients’ are. But some are known endocrine disruptors.

How do inert ingredients alter the toxicity for plants-and more importantly for people?

The ‘inert ingredients’ can alter how an herbicide acts on plants which has implications for peoples’ health in 3 ways:

  • Some inert ingredients alter the “stickiness” of the herbicide on plant tissues, reducing the chances an untimely rain will wash an herbicide off the weed before it has been absorbed. Increased herbicide ‘stickiness’ prolongs and increases human exposures when children, or adults, play on fields sprayed in the recent past.
  • Some inert ingredients are more toxic to certain organisms, including mammals, than the herbicide active ingredient they are mixed into.
  • Many common ‘inerts’ are designed to rapidly move the herbicide from the outside of the weed (i.e., a leaf surface) to inside the weed. The quicker that happens, the more effective it will be. And now the herbicide can no longer be washed off or broken down by sunlight. It can work the same way when people are exposed. Several common inert ingredients also increase the likelihood that an herbicide’s active ingredient will penetrate human skin and find its way into our cells.

what about insecticides?

The two most widely applied classes of insecticides on turf and playing fields are the synthetic pyrethroids and neonicotinoids.
Most widely applied synthetic Pyrethroids include:

• Permethrin (Astro)
• Bifenthrin (Allectus, Talstar)
• Cyfluthrin (Tempo)
• Cypermethrin (Demon)

Currently registered Neonicotinoids include:


• Thiamethoxam (Meridian)
• Imidacloprid (Merit, Lallet)
• Dinotefuran (Zylam)
• Dlothianidin (Arena, Aloft)

In some regions of the country, these higher risk insecticides are still used:

• Organophosphate (OP) (e.g., acephate [Orthene]
• Chlorpyrifos [Dursban]
• Trichlorfon [Dylox]
• Carbamate insecticides carbaryl [Sevin]
• Methiocarb [Mesurol]

If you want to learn more, the EPA lists 24 different types of pesticides on its website and provides clear explanations of the different, major categories.