03
Sep
Pesticide Drift from Farms Turns Habitat and Open Space into Killing Fields for Bees and Biodiversity, Study Finds
(Beyond Pesticides, September 3, 2025) A study in Environmental Entomology shows that habitat and open space near agricultural fields become a killing field of pesticides, threatening biodiversity due to contamination from toxic drift. The study detected 42 pesticides, including several neonicotinoids, which are among the most lethal threats to pollinators. The research reveals the complexity of pesticide flow through the environment and the inadequacy of current methods of protecting nontarget organisms, including honey bees, bumblebees, and hundreds of other species of native bees worldwide. Their catastrophic declines is tied to pesticides in large part and highlights the inadequacy of current pesticide reduction strategies, such as integrated pest management (IPM) and now other loosely defined concepts like “regenerative,†in an attempt to protect the environment and nontarget organisms in chemical-dependent land management and agriculture. (See What the Science Shows on Biodiversity.)
The researchers on the study, from the U.S. Department of Agriculture, Cornell University and Michigan State University, put silicone bands on fence posts in open areas adjacent to highbush blueberry fields on 15 farms in western Michigan. Silicone takes up chemicals in the atmosphere which can then be extracted and analyzed. The fence posts were placed at seven intervals ranging from zero to 32 meters from the blueberry field edges. They were left in place for three weeks in July 2020.
A total of 104 samples from the 15 sites, one for each distance interval, were analyzed. Forty-two pesticides were detected altogether, including several neonicotinoids, which are among the most lethal threats to pollinators. Among the 42 pesticides detected, the herbicide metolachlor is found in all samples, followed by the fungicides azoxystrobin and trifloxystrobin and the herbicide atrazine. Active ingredients detected at the highest concentrations are the insecticides acetamiprid (a neonicotinoid), bendiocarb (a carbamate), malaoxon (a degradate of the organophosphate malathion) and phosmet (an organophosphate). These are found at levels above the upper limit of quantification, that is, higher than the maximum the detection method can confidently identify. The neonicotinoid imidacloprid is also found at very high concentrations. Several fungicides are also detected near or above the upper limit of quantification. Quantification of levels is not always an effective method for determining harm because of the failure of ecosystem studies to fully evaluate mixtures, synergistic effects, nondisclosed “inert,†but chemically and biologically active, ingredients, contaminants in pesticide formulations (including per- and polyfluoroalkyl substances (PFAS), among other hazardous complexities.
One very significant result of the study is the finding that distance has no effect on the number of active ingredients detected—in other words, just as many active ingredients are found at 32 meters from the field as at two meters. There are significant differences in the average concentrations of all pesticides at different distances, with longer distance corresponding to lower concentrations, but this is mostly due to the influence of fungicides in the dataset. For the seven insecticides with high concentrations or frequent detections, there is no difference between distances. The organophosphate phosmet, used primarily on orchard fruits and considered the greatest risk to honeybees during fruit ripening, is also found at similar concentrations at every distance measured.
Efforts to reduce pesticide drift are cited as a mitigation measure. The authors write: using different spray nozzles and spray pressure, reducing the volume of the active ingredient, and slowing tractor speed, for example. However, the researchers write, “[A]doption of drift-reducing practices remains limited across most cropping systems.†(The adverse effect of pesticide drift on biodiversity has been widely studied.) Another way pesticides often migrate in air is through volatilization—that is, after application as a liquid they vaporize and travel in the atmosphere. In this study, the highest concentrations of pesticides found away from the target crop were of low volatility, suggesting that any drift that occurred probably did so during initial application and be captured in sizable buffer zones that would still attract and potentially harm biodiversity. (In a related story, see EPA To Allow Dicamba Herbicide Used in Genetically Engineered Crops, Prone to Drift and Weed Resistance.)
Pesticides are also not the only things that drift. Pollen itself, principally from wind-pollinated plants like corn, drifts for long distances. While pollen drift is not so much an issue for insect and bird-pollinated plants, the advent of genetically modified corn (GMO) varieties has nonetheless created problems for pollinating insects: the genetic modifications enable explosive use of pesticides, as the GMO varieties are tolerant of certain herbicides and insecticides and may be resistant to insects and viruses. These pesticides in turn decimate pollinators.
Pollinators collect both nectar and pollen from flowering plants and transport them back to their nests. These are distributed to all members of a social insect colony, and in both social and solitary pollinators the larvae are exposed. The widespread assumption has been that it is mostly pollen, and secondarily nectar, from treated crops that are the source of the pesticide exposures. There has also been an assumption that pollinators’ pesticide exposure from agricultural applications is diluted by the pollen collected from untreated wildflowers. But strikingly, in a 2015 British study of canola fields treated with neonicotinoids, the total concentration of these insecticides in wildflower pollen from field margins was higher than in the pollen from the crop plants. This was not the case for the nectar samples, and the British researchers suggested that the neonicotinoids in the nectar arrived there via soil contamination. Neonicotinoids are highly water soluble and easily make their way into an entire plant through roots, leaves and the plants’ circulatory mechanisms.
From a larger perspective, it is clear that pesticides, including those that directly affect vital pollinators, do not stay put. A study analyzed by Beyond Pesticides last March found that pesticides drifted all the way from the Rhine Valley floor to the tops of surrounding mountains—distances of up to “multiple hundred meters,†according to the authors. Unfortunately, spray drift is only one of the ways that pesticides migrate around landscapes. According to a recent scientific review, neonicotinoids are applied by soil drenching, root irrigation, foliage spray, injection and seed treatment. The British study also found that crops that had been treated with fungicides but not neonicotinoids contained residues of neonicotinoid mixtures, possibly from contaminated machinery used to process treated seeds or their parent crops.
The Michigan blueberry study adds to the growing evidence that the current norms for protective buffers are wholly inadequate. In western Michigan blueberry fields, a typical width is 16 to 20 meters. “Given this, for the majority of wildflower plantings in this region, the entire planting is likely to be within the area where we found no significant reduction in pesticide concentration with distance from the crop field edge,†the authors write. A frequently suggested optimal buffer size to minimize drift is approximately 10-20 meters and based on wind speed at the time of application. The Michigan authors suggest that the few existing wildflower plantings ranging from two to 10 acres near blueberry fields may provide far better protection than small 32-meter strips along field margins.
Beyond Pesticides has a deep archive of information on pollinators, neonicotinoids, spray drift, and hundreds of pesticides. See the report, “No Longer a BIG Mystery: Recent scientific research confirms the role of pesticides in pollinator decline†and our BEE Protective resource for information on stopping the pollinator carnage.
In 2014 a panel of scientists from Britain and The Netherlands published a paper in the Royal Society Proceedings B entitled “A restatement of the natural science evidence base concerning neonicotinoid insecticides and insect pollinators.†In it, the authors wrote:
There is clear evidence of the great value of neonicotinoids in agriculture as well as the importance of the ecosystem services provided to agriculture by managed and wild pollinators. Pollinators also have intrinsic importance as components of natural biodiversity that cannot, or can only inexactly, be accorded economic value. In some cases, intelligent regulation of insecticide use can provide ‘win-wins’ that improve both agricultural and biodiversity outcomes but in other cases there will be trade-offs, both within and between different agricultural and environmental objectives.
What is clear a decade later is that there are no “win-wins†and the “trade-offs†are so unbalanced as to threaten the entire world’s food supply and the stability of its large-scale ecological balance.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Sources:
Pesticide drift into field margins threatens bee pollinators and other beneficial insects Free
Graham et al.
Environmental Entomology 2025
https://academic.oup.com/ee/article/54/4/835/8161150?login=false
Study Finds High Pesticide Drift Into Wildflower Buffer Zones Near Crop Fields
Andrew Porterfield
Entomology Today 2025
https://entomologytoday.org/2025/08/19/study-high-pesticide-drift-wildflower-buffer-zones-near-crop-fields/
Sampling Finds Pesticides Throughout Environment with Toxic Mixtures from Agricultural Use
Beyond Pesticides, March 28, 2025
https://beyondpesticides.org/dailynewsblog/2025/03/sampling-finds-pesticides-throughout-environment-with-toxic-mixtures-from-agricultural-use/
Neonicotinoid Residues in Wildflowers, a Potential Route of Chronic Exposure for Bees
BotÃas et al.
Environmental Science & Technology 2015
https://pubs.acs.org/doi/pdf/10.1021/acs.est.5b03459?ref=article_openPDF
A restatement of the natural science evidence base concerning neonicotinoid insecticides and insect pollinators
Godfray et al.
The Royal Society Publishing Proceedings B 2014
Proceedings Biological Science
https://pmc.ncbi.nlm.nih.gov/articles/PMC4046413/#s4
Pollinators and Pesticides: Protecting honeybees and wild pollinators
Beyond Pesticides
https://www.beyondpesticides.org/assets/media/documents/pollinators/pollinators.pdf
