Putting the Brakes on Neonicotinoid Pesticide Use
By Joanna Voigt
Since the mid-2000s, there has been a dramatic change in pesticide use in agricultural fields in the US and around the world due to a class of pesticides called neonicotinoids. Currently, over 100 million acres of farmland in the US are planted with neonicotinoid-coated seeds each year. Research has shown that neonicotinoids are being greatly over-used in agricultural fields, with few or no benefits to the farmer in many cases. On the other hand, neonicotinoids are wreaking havoc on pollinators, beneficial insects and other wildlife.
Neonicotinoids, or neonics for short, are systemic pesticides that target sucking insects such as fleas and aphids, and are applied as foliar sprays, soil drenches, and seed coatings. The most prevalent use of neonicotinoids is as a seed coating for corn, soybeans, wheat, canola, cotton, and sugar beets (with corn and soybeans comprising a large majority of crop acres).
The use of neonics as a seed coating has led to unprecedented levels of pesticides being applied to agricultural fields because the seeds are coated with neonicotinoid pesticides prior to planting. This creates a shift from reactive pesticide use (applying pesticides only when and if a problem is detected) to prophylactic, nearly ubiquitous pesticide use in many cases. At least 94% of corn seed planted in the US is coated with neonics, and between 34 – 44% of soybean seed is coated.
Numerous studies have shown that neonicotinoids have very little, if any, impact on yields for many crops. Dr. Christian Krupke, Purdue University, who has done extensive research on neonicotinoids, concludes, “We have not demonstrated a consistent yield benefit of neonicotinoid seed treatments in either case [corn or soybeans] over many sites and many years.” (Kleinschmit 2015) Other studies posit similar conclusions:
- In October 2014, the EPA published a study that analyzed the effectiveness of neonicotinoids in soybean production and found that neonicotinoids “provide little or no benefit for soybean production in almost all cases.” (Kleinschmit 2015)
- In December 2015, 12 universities, including Kansas State University, jointly published a report, “The Effectiveness of Neonicotinoid Seed Treatments in Soybean.” The report states that, “Neonicotinoid seed treatments offer soybean plants a narrow window of protection…against early pests, in targeted high-risk situations.” The report points out that this scenario is almost never present in northern states, and that, “The current use of neonicotinoid seed treatments in soybean and other crops far exceeds pest pressures.”
- In May 2017, the Center for Food Safety released a report detailing lack of evidence of neonicotinoid efficacy in corn. The report states that, “It is uncommon for neonic seed coatings to increase corn yield.” The report goes on to say, “Some research suggests that neonic seed coatings may sometimes actually decrease yields or reduce profit. This may occur because neonics may reduce the populations of organisms that normally help keep pest insects in check.”
As the 12-university study above points out, it is not because neonicotinoids are not toxic enough that there are few benefits to using them, but rather that the timing of their efficacy does not coincide with incidence of target pests, or because the pressure from targeted pests is negligible enough that yield is not impacted by use of the pesticide. On the other hand, these pesticides are hitting pollinators and other beneficial insects hard.
While planting neonic-coated seeds was originally touted as being environmentally superior to spraying pesticides, deemed a more targeted and self-contained approach, this has not turned out to be the case. Neonicotinoid-laden dust is kicked up and dispersed through the air during the planting of neonicotinoid-treated seeds. Once the seed is in the ground, only 2 – 20% of the pesticide is taken up by the plant, leaving a large quantity of the pesticide to work its way into the surrounding environment. Neonicotinoids are water soluble, allowing for easy dispersal to new locations, and they are highly persistent, remaining viable for weeks to years. As a result, neonics are turning up and accumulating in all kinds of places, including soil, non-target vegetation, surface water, beehives, and our food supply.
- A 2012 Purdue University study found neonics not only “…in the soil in the fields that were planted [with neonic-coated seeds], but more worryingly also in fields that weren’t planted.” (Kleinschmit 2015)
- A 2015 US Geological Survey found neonicotinoids in more than half the water samples collected from streams throughout the US. Prevalence of neonics in streams in the Midwest is even greater, owing to large acreages of corn and soybeans. (Kleinschmit 2015)
- A 2016 study published in Scientific Reports detailed finding neonics in vegetation in pollinator strips that had been planted on organic farms with the specific intention of providing neonicotinoid-free habitat and resources for bees and pollinators.
The pollinator strips had been planted more than 140 meters from fields where neonic-coated seeds were planted, which is the recommended buffer zone. Nevertheless, neonics were found in the vegetation in the pollinator strips as well as in honey bees and hive products from hives located on the organic farms.
In addition to finding their way into the environment surrounding agricultural fields, neonics are winding up in the human food and water supply.
- A 2015 study at the Harvard T.H. Chan School of Health found that “…more than 70 percent of pollen and honey samples collected from foraging bees in Massachusetts contain at least one neonicotinoid.”
- In April 2017, a team of chemists and engineers from the USGS and the University of Iowa reported that they had found neonicotinoids in the drinking water supply in Iowa City, Iowa. (Guarino 2017)
- A 2015 study by the American Bird Conservancy (ABC) and the Harvard T.H. Chan School of Public Health found neonicotinoids in “…nearly every food eaten by the nation’s Senators, Representatives, and others who dine in the cafeterias of the United States Congress.” The study found that, “In two rounds of testing – the first in January and the second in May of 2015 – nearly all Congressional cafeteria food tested positive for one or more neonicotinoid insecticide residues.
Sixty out of a total of 66 food samples, or 91%, tested positive for the chemicals. Forty-seven (or 71%) of the foods had two or more neonicotinoids.” (ABC 2015)
While studies on the impacts of neonicotinoids on human health are scarce as yet, the impacts of neonicotinoids on pollinators, birds, invertebrates and other wildlife have been well-documented.
Neonicotinoids are highly toxic to bees and many other pollinators and beneficial insects. Both acute exposure to neonicotinoids and chronic exposure to neonicotinoids at low levels are harmful and can be lethal to many pollinators. US beekeepers are reporting hive losses of greater than 50% per year, causing many beekeepers to close up shop and creating a shortage of bees to pollinate crops such as almonds and blueberries, which are highly pollinator-dependent. While measuring the impacts of neonicotinoids on native bees is challenging since native bees are not generally in managed colonies, studies have shown that neonicotinoids are highly toxic to bumble bees at acute levels of exposure, and have debilitating impacts at low levels of exposure, over time.
There are a number of avenues through which pollinators can be exposed to neonicotinoids in the agricultural setting. During the planting of neonicotinoid-coated seeds, when pesticide-laden dust is kicked up, pollinators that encounter the dust often experience immediate and devastating impacts, with large numbers of bees dying or becoming disoriented.
Sub-lethal amounts of neonicotinoids are encountered when bees and pollinators utilize the pollen, nectar or guttation fluid of plants grown from neonic-coated seeds, or through off-target vegetation and water sources that have been contaminated with neonics.
Even at very low levels, chronic exposure to neonicotinoids has been shown to cause changes in foraging behavior, reduced predator avoidance, delayed development and reduced reproductive success in honey bees, and leads to declining health and reproductive success in bumblebees.
Studies have shown that ingestion of even one neonicotinoid-coated seed is enough to kill a songbird, and that ingestion of as few as five coated seeds can kill a turkey. A study by Dr. Jonathan Lundgren, former USDA-ARS entomologist who studied neonicotinoids extensively, found neonicotinoids in the livers of 50% of deer analyzed in the study.
So Why Do Farmers Use Neonics?
With all these negative impacts, and so few benefits, why do farmers continue to use neonicotinoids? There are a number of reasons:
- Farmers are accustomed to planting coated seeds. Seed treatments have been around for years and unless a farmer grows organically, she or he may never have planted a seed that wasn’t coated with something. Many seeds are coated with a number of treatments, including fungicides, plant growth regulators, and nematicides, in addition to pesticides. The cocktail of treatments is often applied to seeds long before the farmer makes the purchase, with the seed dealer or co-op making the choice and simply relaying the intended benefits to the farmer. Unless a farmer really digs into it, he or she might not know exactly which coatings are on the seed, let alone the impacts that the coatings have on the surrounding environment and organisms.
- Seeds are a major investment, and neonicotinoids have been intensively marketed as a cheap insurance policy. In recent decades, seed technology has become increasingly complex, commodity crop prices rose to record highs (for a time), and farms have multiplied in size, making seed purchase a major investment for a farmer. Neonicotinoids have been touted as an inexpensive insurance for these seeds. Because of the prophylactic nature of application, there is little way for a farmer to judge efficacy, and the risk of not doing what the seed company recommends can be daunting.
- Access to non-coated seeds is limited. Because of the structure for purchasing agricultural seed in the US, it can be difficult or nearly impossible for farmers to purchase conventional seeds that have not been treated with neonicotinoids. Corn is coated with neonicotinoids long before it gets to the point of purchase, making purchasing non-coated corn seed challenging. Soybeans are treated “downstream,” at the co-op or seed dealer, and so access to non-coated soy should be somewhat easier. However, there may be significant pressure from the seed company, dealer or co-op, or a perception of risk, or fear of going against the grain that steers farmers towards purchasing coated seeds.
- Information about the lack of efficacy and negative impacts of neonicotinoids is lacking. Only recently have studies on the lack of efficacy been published, and the information has not been widely distributed to farmers. On the other hand, farmers are bombarded with information and sales pitches for the various seed coatings and their intended benefits. Likewise, studies concretely tying pollinator decline to neonicotinoids have only recently begun to have traction in mainstream media and farm press.
Because of the lack of benefits to farmers and the widespread negative impacts neonicotinoids have on pollinators, other insects and wildlife, and the environment, it would behoove us to move away from the use of neonicotinoid pesticides. This should not be a move towards other pesticides, which inevitably have their own set of issues, but a move towards diverse, healthy farming systems that do not depend on synthetic pesticides in order to keep pest pressures at reasonable levels.
As Dr. Jonathan Lundgren, entomologist and agro-ecologist, pointed out in his keynote address at KRC’s 2016 Farm & Food Conference, “The problem isn’t pests, but a lack of diversity and too much disturbance. If you have a pest problem in your field, it’s because something in your field is out of whack.”
In order to bring fields back into “whack,” diversified farming systems can be utilized. Such systems “…intentionally include functional biodiversity at multiple spatial and/or temporal scales in order to maintain ecosystem services that provide critical inputs to agriculture, such as soil fertility, pest and disease control, water use efficiency, and pollination.” (Kremen 2012) That means use of complex crop rotations, mixed species cover crops, and mixes of annuals and perennials in the rotation which all increase beneficial insects and soil microorganisms. These systems are being utilized successfully by farmers in Kansas and across the US. Focusing on increasing diversity, building soil health, and reducing disturbance will reduce the need for pesticides.
Putting the brakes on neonicotinoid use and aiming for a farm and food system that supports healthy, functioning ecosystems also helps the farmer as he or she takes back control of or eliminates their inputs. Ultimately, these decisions enhance economic and human health, too.
American Bird Conservancy, and Harvard T.H. Chan School of Public Health. “Members Of Congress Dining On Food Contaminated With Bird- And Bee-Killing Insecticides Chemicals Found in Dining Hall Food Have Been Restricted by the European Union due to Deadly Impacts on Pollinators.” https://abcbirds.org/article/members-of-congress-dining-on-food-contaminated-with-bird-and-bee-killing-insecticides/.
Center for Food Safety. “Alternatives to Neonicotinoid Insecticide-Coated Corn Seed: Agroecological Methods are Better for Farmers and the Environment.” May 2017.
Guarino, Ben. “First evidence found of popular farm pesticides in drinking water.” The Washington Post. April 5, 2017.
Kleinschmit, Jim, and Ben Lilliston. “Unknown Benefits, Hidden Costs: Neonicotinoid Seed Coatings, Crop Yields and Pollinators.” Institute for Agriculture and Trade Policy, August 2015.
Kremen , Claire, Alastair Iles, and Christopher Bacon . “Diversified Farming Systems: An Agroecological, Systems-based Alternative to Modern Industrial Agriculture.” Ecology and Society. Vol. 17. No 4. 2012.
Krupke, et al. “The Effectiveness of Neoniotoinoid Seed Treatments in Soybean.” Purdue Extension. December 2016.
Mogren, Christina L., and Jonathan G. Lundgren. “Neonicotinoid-contaminated pollinator strips adjacent to cropland reduce honey bee nutritional status.” Scientific Reports. July 2016.
This article was produced with funding from Ceres Trust.
Contact Joanna Voigt at email@example.com