Do You Know Your EIQs?
Integrated Pest Management (IPM) is widely accepted as the best way to balance pest control with environmental considerations. Through IPM, pesticides are avoided until monitoring, identification, history, and action thresholds indicate that pest control is required. At that point, a good IPM program evaluates the proper control method both for effectiveness and environmental risk. But while data exists to measure effectiveness, how do you measure risk?
While a wealth of environmental impact data is available for pesticides (largely because of the registration process), for many years it was not organized in a meaningful way. As a result, applicators had very few tools to determine the lowest risk pesticide. They could take note of signal words (Caution, Warning, Danger) to try to make the best decision, but it was not ideal. Yet today, there are methods to help determine the environmental impact of pesticides. One was developed by Cornell University in 1992, yet few landscapers know about it.
The Magic Formula
Nearly three decades ago, in an effort to create a uniform and more user friendly method of risk evaluation, scientists from the New York State Agricultural Experiment Station at Cornell University published “A Method To Measure the Environmental Impact of Pesticides.” In it, they introduced the Environmental Impact Quotient.
The Environmental Impact Quotient is a single number that rates a pesticide’s environmental impact on a scale from 6.7 to 226.7. The lower the number, the lower the environmental impact. As a standard criteria, the Environmental Impact Quotient (EIQ) now allows applicators to compare environmental impacts through a more focused lens.
Yet not everyone supports the idea. “There is a lot of debate among people who study toxicology about synthesizing all this data into one number,” says Carl Schimenti, Cornell turf research program manager. “There are hundreds of these models, each weighting properties of each pesticide differently. There is actually a good bit of literature suggesting the EIQ isn’t great, but no one offers a better alternative.”
To formulate the EIQ, Cornell scientists considered several factors, which can get quite technical, but very basically include: toxicity, soil half-life, systemicity, leaching potential, plant surface half-life, and surface loss potential. These factors are meant to consider the overall effects on the applicator, consumer, and ecology. After data on all these factors are collected, pesticides are grouped by class (insecticides, herbicides, etc.) and calculations are made. The result is the EIQ.
So why don’t most landscapers know about EIQ? Schimenti says it’s likely a combination of factors. For one, EIQ is not a pesticide reporting requirement. Additionally, “many focus… on economics and efficacy. Adding the additional variable of ‘environmental’ can be perceived as [complicating] the decision-making process.” And while extension agents are familiar with EIQ, says Schimenti, they’re generally there to answer questions. If the questions aren’t being asked, it’s difficult to drive education.
EIQ Use In The Field
Of course, different products have different formulations. For this reason, EIQ field use ratings (EIQ-FUR) were developed to gain a more accurate picture. In other words, it’s not just the chemical itself, it’s the amount of chemical used in application. So EIQ-FUR calculations further consider: the formulation (or percentage of active ingredient) and the frequency of application. Simply multiply the EIQ of a specific chemical by the percent active ingredient and by the rate used (usually in pints or pounds of product per acre.) To clarify: EIQ FUR = EIQ x % Active Ingredient x Rate.
Luckily, Cornell has made it easy with an online EIQ-FUR calculator (pictured above). Just plug in answers for three simple steps and it does the math. A link to the online Calculator is provided at the end of the article on this page.
Pesticides should be compared based on the EIQ-FUR of the product only, not by the base EIQ. For instance, a product may have low EIQ compared to others based on its active ingredient, yet when formulations are taken into account, it could rise higher in the ranks, or vice versa. The lower the EIQ-FUR, the lower the environmental impact. As one pesticide educator put it: If a pesticide is needed and all else is equal, picking the least risky pesticide is easy:
- Figure out what the target pest is.
- Determine the products available to control the pest.
- Plug the AI and Rate into the EIQ Calculator.
Small differences in the EIQ-FUR are not meaningful, rather the relative level and ranking are. Cornell provides the following guide for landscape and turfgrass managers:
- <25 very low
- <50 low
- 50-100 moderate
- >100 high
- >150 very high
The EIQ FUR can be used to compare different pest management strategies, and to compare seasonal totals from year to year. To do so, calculate the EIQ-FUR for each application for the season and simply sum them up.
Pesticide products differ in efficacy, mode of action, potential for causing resistance, and cost. A landscaper should consider all these differences when selecting a pesticide and overall management strategy. Adding the environmental impact to these considerations—using the EIQ-FUR model—simply enhances your ability to make well-informed choices.
Want to know the EIQ-FUR of products you use? Or make a product comparison? Visit the Calculator for Field Use EIQ.
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