JoAnne Skelly: Understanding pesticides

JoAnne Skelly

JoAnne Skelly

I was listening to National Public Radio recently on the most recent data about the “Dirty Dozen” vegetables and fruits with the most pesticide residue as well as those with the least.
The interviewer asked the researcher, “So we should avoid vegetables and fruits on which pesticides have been used?” He made it sound as if organic food was pesticide-free, which is not the case. Let me explain.
A pesticide is “any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest and any substance or mixture of substances intended for use as a plant regulator, defoliant, or desiccant,” (
Usually, commercial agriculture uses synthetic, non-organic pesticides while organic producers generally use non-synthetic ones. Non-synthetic pesticides are substances “that are derived from mineral, plant, or animal matter and do not undergo a synthetic process (USDA). Many things are pesticides such as herbicides (weed-killers), insecticides, fungicides, anti-biotics (kills bacteria), miticides (mite killers), and rodenticides (kills rodents) to name a few. Even things like dish soap, vinegar and bleach can be pesticides.
“The pesticides that are allowed for organic food production are typically not manmade. They tend to have natural substances like soaps, lime sulfur and hydrogen peroxide as ingredients. However, not all natural substances are allowed in organic agriculture; some chemicals like arsenic, strychnine and tobacco dust (nicotine sulfate) are prohibited (National Pesticide Information Center,
Rotenone, a plant-based insecticide is also prohibited due to its toxicity and potential damage to the environment. This is an example of a non-synthetic pesticide that is as or more toxic and damaging than a synthetic counterpart. Just because a product is natural or organic doesn’t always equate to safe, particularly if the dose is too high or it’s applied too often.
The Rodale Institute blog states “Almost all natural materials are approved for use in organic. Take, for example, neem oil. Neem oil is derived from the seeds of the neem tree. It has been used for hundreds of years to minimize pests and plant diseases. Neem oil is natural and approved for use in organic” (
Diatomaceous earth, non-detergent insecticidal soaps, sticky traps, pheromone traps, horticulture oils and corn gluten are additional examples of allowed organic pesticides. They point out that there are some synthetic substances allowed in organic farming, if there are no naturally occurring alternatives. Copper is an example.
No matter whether a pesticide is synthetic or non-synthetic, always read the label and use properly with the correct protective gear, at the right time of day or season and for the targeted pest.
For a detailed list of pesticides allowed in organic food production:


Use the comment form below to begin a discussion about this content.

Sign in to comment