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This post is a continuation of my previous article on the topic of natural vs. synthetic. Today, we are going to examine how to select pesticides that pose a low risk to humans and the environment. You can find the first article HERE.

In today's world, the American consumer often relates the terms "natural" or "organic" to "safe." In the world of horticulture, this poor distinction is often made when discussing pesticides.

First, some clarifying statements:

  • Pesticides are products made to kill living organisms
  • Pesticides are regulated by the federal government
  • Pesticides can be synthetic or organic
  • An ornamental or food crop labeled as "organic" does not mean pesticide free. Instead, these growers may use organic pesticides
  • There are many levels of the term organic. USDA Certified Organic is a term defined by the government that specifies what may be used on/in the product.

There is one way the government indicates the acute (immediate) toxicity of a pesticide to humans. On each pesticide container, you will see one of three signal words: Caution – least toxic, Warning – mildly toxic, and Danger – highly toxic. Usually, skull and crossbones accompany the signal word Danger. As if Danger wasn't enough of a clue, hopefully, the skull and crossbones get the point across that this category of pesticides has no place in the home landscape.

Another way to measure the risk of using a pesticide is with the Environmental Impact Quotient (EIQ). The EIQ examines three parts 1) Risk to the applicator, 2) Risk to the consumer of the product, and 3) Risk to the environment. These three categories are scored and then averaged to come up with one EIQ number. The higher EIQ means greater chances for a negative impact on people and the environment. Low EIQ means a lower chance for negative impact. Companies are not required to list a product's EIQ, but these are easily found online. Cornell Extension has a spreadsheet on their website listing every active ingredient found in regulated synthetic and organic pesticides and their corresponding EIQ.

When having to decide on what pesticide to use, I use Cornell's EIQ spreadsheet to identify those that pose the lowest risk to me and the environment. For instance, the synthetic herbicide glyphosate (RoundUp) has an EIQ of 15, which is pretty good and poses a lower risk than many other herbicides. The organic insecticide Bacillus thuringiensis (Bt) has a very low EIQ of 7.9. Conversely, the organic fungicide copper sulfate has an EIQ of 61.9. That is really high!

Some EIQ numbers are higher not because they harm humans, but they pose a high risk to the environment. That is why I like the EIQ system as it takes into account the risks to me and the environment. But keep in mind the EIQ scores are not perfect. There are a few that could be ranked higher. Ideally, I try to stick to products with an EIQ under 20.

Hopefully, this article shines some light on the organic vs. synthetic debate, and that "natural" does not indicate "safe." Evaluating pesticides needs to be on a case-by-case basis. Reduce the amount of pesticides, no matter what type you use. When turning to pesticides evaluate them based on their effectiveness and safety, not organic vs. synthetic. And always read and follow pesticide labels.