Reducing Pesticide Use On Farms

Dr. Paul Jepson is an ecologist and professor at Oregon State University, whose work on integrated pest man­agement (IPM) and pesticide risk assessment spans more than three decades and has taken him across the globe. Dr. Jepson helped revise the 2010 Sustainable Agriculture Network Standard, used by the Rainforest Alliance. In this capacity, his particular focus was on helping to develop the approach to IPM and the new pesticide hazard elimination and risk mit­igation framework that is used in the 2017 Rainforest Alliance Sustainable Agriculture Standard. Rainforest Alliance scientist Deanna Newsom spoke with Dr. Jepson to discuss his work on IPM and pesticide risk management.

Deanna Newsom: The new standard not only expands the list of prohibited pesticides from 100 to 150 substances, but it also requires farmers to undertake risk mitigation practices for an additional 170 permitted pesticides. Why are these new requirements necessary?

Paul Jepson

Paul Jepson

Photo credit: Oregon State University

Paul Jepson: Imagine you’re a farmer, and you’re using three different chemicals out in the field. One might be a herbicide that you apply before you plant so that the young crop isn’t outcompeted by weeds. Then maybe there’s a disease that threatens your crop, so you apply a fungicide. And later in the season, you use an insecticide to kill off a pest. Under both the 2010 and 2017 standards, if any of these chemicals is on the prohibited list, you must stop using it and find an alternative. But the reality is that many of the alternative pesticides also pose a risk to the environment and human health if used incorrectly. That’s why we developed the risk mitigation framework—to address those cases. I should add that these uses for pesticides must also now be justified as part of an integrated pest management (IPM) program. This encourages farmers to identify alternative pest control measures and thereby reduce pesticide use.

DN: How does the new risk mitigation approach work?

PJ: If you’re the farmer above, it’s possible that the insecticide you’re using is permitted but is especially toxic to fish. However, this risk can be substantially mitigated if you apply some simple practices. For instance, maybe you will need to avoid spraying it within a certain distance of a stream. Maybe you will need to use a certain application nozzle on your sprayer that minimizes drift. Or perhaps you will need to delay spraying if the wind is blowing in a certain direction. All of these risk mitigation measures are scientifically based, tried and tested, and are not particularly onerous for farmers. And most of these mitigation measures can be found right there on the label of the products sold in the USA or Europe, but they’re missing from the labels of the same products when they are sold in developing countries. With the new standard, we’ve simply codified this risk management approach to make it easy for farmers to know which practices to apply, and when they need to apply them, to mitigate the most significant environmental and health risks.

DN: Your team has already tested this approach in West Africa. How have farmers there responded?

PJ: We were really impressed by the degree to which farmers complied with risk-based information once they understood the basis for it. But it’s also clear that farmers need knowledge about the basic concepts, such as the health risks associated with dermal exposure, in order to believe what we’re telling them. We must help farmers understand that a leaf can look green and healthy but actually poses a huge health risk to them and their family if an invisible spray deposit is present. That’s difficult. There’s a lack of translation of science into the public domain. We’ve found that pictograms and other symbol-based training materials, when used within participatory education programs, have been very effective in West Africa. And when we show these same training materials to farmers in Oregon, they say, “Wow, that is so much easier for me, too.”

"The new standard adds much more structure and science to the process, which increases the likelihood that changes made by farmers will benefit their productivity, as well as protecting their families and wildlife."

Paul Jepson, Oregon State University

DN: It’s good to hear that farmers are receptive, but what are the implications of these risk mitigation practices for farm management? Are farmers able to combat pests effectively and maintain farm productivity?

PJ: We often refer to the “pesticide treadmill,” which still runs in many crops globally, even in the U.S. This treadmill of use often occurs when farmers apply pesticides more and more frequently because the naturally occurring predators of pests are gone, usually killed by broad-spectrum pesticides. We’re trying to pull away from this phenomenon by creating a tool that certification programs can use to help farmers reduce pesticide dependency. But until farmers see that they can maintain productivity with much lower pesticide use, it can feel to them like a risky thing to try. The transition needs to happen gradually, and it can take two or three years, during which time predator populations can recover, if the conditions are right.

DN: You’ve sat on international advisory councils before. What was it like working on a certification standard?

PJ: I really believe in certification and what the Rainforest Alliance is doing. When you work on non-certified farms in the developing world, farmers say, “Yes, I feel sick; yes, I’m noticing that this chemical is toxic; yes, I’ll do what I can to minimize my exposure. But I have no choice—I have to use it.” The Rainforest Alliance is helping to provide farmers with an alternative. The new standard adds much more structure and science to the process, which increases the likelihood that changes made by farmers will benefit their productivity, as well as protecting their families and wildlife. It’s like the layers within an onion—we’ve added more layers of protection. One could always go further, but with the new standard, we’ve built in the key elements of IPM and the mitigation of environmental and health risks. And we’ve done this in a way that I think farmers can actually adopt.

Pesticide safety sign

At Falcon Farms, a Rainforest Alliance Certified flower farm in Colombia, a sign informs workers when an area has been treated with pesticide, and when it will be safe to re-enter.

DN: Can you tell us what’s next for your research program?

PJ: In west and southern Africa, we’re working on a risk index that is specific to knapsack sprayer applicators. We’re also quantifying the amount of time that people should wait before entering fields that have been sprayed. Pesticide labels often recommend waiting one day, or until the chemical deposits are dry, but with some pesticides we are finding that people actually need to wait a number of weeks to be safe.


Forest canopy - photo by Sergio Izquierdo

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