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Insecticide (Neonics) Harm to Biodiversity

About two-thirds of terrestrial species are insects.[1] Because insecticides are designed to kill insects, they reduce both the number and diversity of all insects – not just those that are targeted. Insect species are in severe decline.[2,3]

Diverse and healthy populations of insects are critical to ecosystems and to life on earth. Insects “create the biological foundation for all terrestrial ecosystems. They cycle nutrients, pollinate plants, disperse seeds, maintain soil structure and fertility, control populations of other organisms, and provide a major food source for other taxa.”[4] Thus, the severe decline of insect populations indirectly impacts all of biodiversity.

The most widely used insecticides, neonicotinoids (aka neonics), accumulate in soils, killing a wide range of invertebrate life; the eventual runoff severely degrades aquatic systems.[5-7] Neonics are pervasive throughout the U.S. environment.

 

  1. Sánchez-Bayo, F. & Wyckhuys, K. A. G. (2019). Worldwide decline of the entomofauna: A review of its drivers. Biological Conservation, 232, 8–27, p. 9.
  2. Sánchez-Bayo, F. & Wyckhuys, K. A. G. (2019), Abstract. [“Our work reveals dramatic rates of decline that may lead to the extinction of 40% of the world’s insect species over the next few decades.”]
  3. Goulson, D. (2019). The insect apocalypse, and why it matters. Current Biology, 29(19), R967-R971, Abtract. [“Recent studies from Germany and Puerto Rico suggest that insects may be in a state of catastrophic population collapse: the German data describe a 76% decline in biomass over 26 years, while the Puerto Rican study estimates a decline of between 75% and 98% over 35 years.” Summarizes results of two highly cited reports.]
  4. Scudder, G. E. (2009). The importance of insects, In Insect biodiversity: science and society, Robert Foottit & Peter Adler (eds.), p. 10.
  5. Gunstone, T., et al., (2021). Pesticides and Soil Invertebrates: A Hazard Assessment. Frontiers in Environmental Science, 9. [“Because 80% or more of the active ingredients from neonicotinoid seed treatments remain in the soil, soil organisms in these systems are likely to be exposed to high doses of these insecticides.”]
  6. Bonmatin, J. M., et al., (2015). Environmental fate and exposure; neonicotinoids and fipronil. Environmental Science and Pollution Research International, 22(1), 35–67, p. 35. […the half-lives of neonicotinoids in soils can exceed 1,000 days, so they can accumulate when used repeatedly.”]
  7.  Sánchez-Bayo, F., et al., (2016). Contamination of the Aquatic Environment with Neonicotinoids and its Implication for Ecosystems. Frontiers in Environmental Science, 4, Abstract. [“The widespread use of systemic neonicotinoid insecticides in agriculture results first in contamination of the soil of the treated crops, and secondly in the transfer of residues to the aquatic environment.”]

According to USGS and EPA scientists, neonicotinoids (neonics) are the most widely used insecticides in the world.[1,2] They are almost certainly the most widely used insecticide in the U.S.[3]

Because neonics are widely used, highly toxic, and uniquely destructive to biodiversity, we focus on them on this page.[4,5]

The great majority of neonics are applied as seed treatments (seeds coated with neonics before planting).[6]

In 2018, the European Union almost completely banned the use of the 3 most common neonics.[7]

 

  1. Hladik, M. L., et al., (2018). Year-round presence of neonicotinoid insecticides in tributaries to the Great Lakes, USA. Environmental Pollution (1987), 235, 1022–1029, p. 1022. 
  2. Barmentlo, S. H., et al., (2021). Experimental evidence for neonicotinoid driven decline in aquatic emerging insects. PNAS, 118(44), e2105692118. p. 1. [“Neonicotinoids were first introduced in 1991 and are currently the most widely used class of insecticides globally.”]
  3. For more details on neonics and their usage, see Insecticides (Neonics) Overview and Neonics Use on Feed Crops
  4. DiBartolomeis, M., et al., (2019). An assessment of acute insecticide toxicity loading (AITL) of chemical pesticides used on agricultural land in the United States. PloS one, 14(8), e0220029, p. 22. [“The neonicotinoid insecticides, in particular imidacloprid, clothianidin, and thiamethoxam, are primarily responsible for this increased toxicity loading, accounting for 61 percent (via contact toxicity) to 99 percent (via oral toxicity) of the total toxicity loading of all insecticides in 2014.”]
  5. John F. Tooker (2022) Farmers are overusing insecticide on seeds, with mounting harmful effects on nature, Louisiana Illuminator. https://lailluminator.com/2022/02/22/farmers-are-overusing-insecticide-on-seeds-with-mounting-harmful-effects-on-nature/ [This entomologist and neonics researcher provides a good overview of the issues.
  6. Douglas, M. R. & Tooker, J. F. (2015). Large-Scale Deployment of Seed Treatments Has Driven Rapid Increase in Use of Neonicotinoid Insecticides and Preemptive Pest Management in U.S. Field Crops. Environmental Science & Technology, 49(8), 5088–5097, p. 5092 [“From 2000 to 2012, virtually all neonicotinoids applied to maize, soybeans, and wheat were applied as seed treatments.”]
  7. European Commission on Food Safety (n.d.) Some facts about neonicotinoids. https://food.ec.europa.eu/plants/pesticides/approval-active-substances/renewal-approval/neonicotinoids_en [“the conditions of approval of the active substances imidacloprid, clothianidin and thiamethoxam have been published in the Official Journal of the European Union on 30 May 2018. As a result, all outdoor uses of the three substances are banned and only the use in permanent greenhouses remains possible.”]

 Neonics are almost certainly the most widely used insecticides in the U.S.
They are far more toxic and persistent than previous types of insecticides, and applied across much more crop acreage.
They are especially damaging to target and non-target insects, birds, bees, soil invertebrates, and aquatic species.
About 75% of neonics are used on corn and soybeans.
About half of all neonic usage goes on that share of crops specifically used for animal feed.
No federal agency tracks total neonic usage.
The EPA has been almost completely ineffective in managing the threats to biodiversity.
Many reports have found neonics provide little to no benefits to farmers.
Farmers have lost control over the decisions to use neonics on their seeds and often don’t know what treatments they are using.
The continued use of neonics, in the face of clear evidence of severe harm, is one of the most destructive practices of industrial animal agriculture.[1]

 

  1. Details and references are provided on this page, as well as Insecticides (Neonics) Overview and Neonics Use on Feed Crops

The share of neonics used for animal feed is likely at 50% or more based on the following:

As a broad estimate based on credible but dated information (due to the cessation of tracking by the USGS), ~75% of total U.S. neonic usage is applied to corn and soybeans, with the vast majority applied as seed treatments.[1,2] Virtually all field corn and more than half of all soybean acres are planted with neonic seeds.[3] 

Therefore, almost half of all neonics are applied to corn and soybeans specifically used for animal feed.[4] Including those portions of secondary crops such as sorghum, wheat, and canola that also go to animal feed and are routinely treated with neonics,[5,6] brings the total of neonics used for animal feed to 50% or more.

 

  1. Tooker, J. F., et al. (2017). Neonicotinoid seed treatments: limitations and compatibility with integrated pest management. Agricultural & Environmental Letters, 2(1), ael2017-08, p. 4. [“Current use of NST (neonic seed treatment) —on nearly 100% of corn acres and >50% of soybean acres—far exceeds historic benchmarks for insecticide use in these crops.”]
  2. Douglas, M. R. & Tooker, J. F. (2015). Large-Scale Deployment of Seed Treatments Has Driven Rapid Increase in Use of Neonicotinoid Insecticides and Preemptive Pest Management in U.S. Field Crops. Environmental Science & Technology, 49(8), 5088–5097, p. 5092. [“From 2000 to 2012, virtually all neonicotinoids applied to maize, soybeans, and wheat were applied as seed treatments.”]
  3. John F. Tooker (2022) Farmers are overusing insecticide on seeds, with mounting harmful effects on nature, Louisiana Illuminator. https://lailluminator.com/2022/02/22/farmers-are-overusing-insecticide-on-seeds-with-mounting-harmful-effects-on-nature/ [“Almost every field corn seed planted this year [2022] in the United States will be coated with neonicotinoids, the most widely used class of insecticides in the world. So will seeds for about half of U.S. soybeans and nearly all cotton, along with other crops.”]
  4. Because of the lack of data from federal agencies, this is necessarily a broad estimate based on dated information. The assumptions are: a) About 75% of neonics are used on corn and soy, b) Corn is ~53% of total neonic applications. c) Soybeans are ~22% of total applications. d) Corn for animal feed is ~64% of total corn. e) Soybeans for animal feed is 58%. (See “Total Feed Crops Share.”) Then (.64 * .53) + (.58 * .22) = 33.9% + 12.8% = 46.7% of all neonic usage is on corn and soy. Adding the many other neonic usages on crops partially used for animal feed including wheat, cotton, and sorghum, among others – together probably brings usage to 50% or more for animal feed. This is a broad estimate based on 2014 USGS data as analyzed by: Tooker, J. F., et al. (2017) and a close evaluation of Fig. 1 from p. 3. For further info, see, Neonics Use on Feed Crops 
  5. U.S. EPA (August 30, 2018) Memorandum: Benefits and Impacts of Potential Mitigation for Neonicotinoid Seed Treatments on Small Grains, Vegetables, and Sugarbeet Crops, p. 6.
  6. U.S. EPA (December 23, 2019) Memorandum: Biological and Economic Analysis Division’s (BEAD) Response to Comments on the Preliminary Risk Assessments and Benefit Assessments for Citrus, Cotton, Soybean Seed Treatment, and Other Crops Not Assessed for Neonicotinoid Insecticides, p. 9.

So-called “conventional” insecticides are usually sprayed on soil or on foliage. Neonics are predominantly applied to seeds before planting.[1] A small amount of neonics, typically less than 10%, gets absorbed into the plant and becomes systemic throughout tissues and foliage. About 90% of the active ingredients is dispersed into the environment.[2,3]

Although the volume by weight is small compared to conventional insecticides, the toxicity and persistence are unusually high.[4,5] Whereas conventional insecticides have half-lives under 30 days, neonic residues may remain in the soil for several years.[6,7]

The use of neonics has, according to some researchers, moved insecticide treatments from a more conventional “as-needed” basis to a full-on, yearly, broad-spectrum approach.[8,9]

 

  1. Douglas, M. R. & Tooker, J. F. (2015). Large-Scale Deployment of Seed Treatments Has Driven Rapid Increase in Use of Neonicotinoid Insecticides and Preemptive Pest Management in U.S. Field Crops. Environmental Science & Technology, 49(8), 5088–5097, p. 5092. https://doi.org/10.1021/es506141g
    [“From 2000 to 2012, virtually all neonicotinoids applied to maize, soybeans, and wheat were applied as seed treatments.”]
  2. Wood, T. J. & Goulson, D. (2017). The environmental risks of neonicotinoid pesticides: a review of the evidence post 2013. Environmental Science and Pollution Research International, 24(21), 17285–17325, p. 17285. [“However, only approximately 5% of the neonicotinoid active ingredient is taken up by crop plants and most instead disperses into the wider environment.”]
    Sánchez-Bayo, F., et al., (2016). Are bee diseases linked to pesticides?—A brief review. Environment international, 89, 7-11, p. 10.
  3. Tooker, J. F. et al., (2017). Neonicotinoid Seed Treatments: Limitations and Compatibility with Integrated Pest Management. Agricultural & Environmental Letters, 2(1), 1–5, p. 4. [“The amount of neonicotinoid applied to seeds that actually gets absorbed by plants is typically about 1 to 10%; the rest remains in soil where it is vulnerable to leaching.”]
  4. DiBartolomeis, M. et al., (2019). An assessment of acute insecticide toxicity loading (AITL) of chemical pesticides used on agricultural land in the United States. PloS one, 14(8), e0220029, p. 5. [“Neonicotinoids are primarily responsible for this increase (in acute toxicity), representing between 61 to nearly 99 percent of the total toxicity loading in 2014.” at p. 1. “…neonicotinoid residues from seed treatments may be found in the soil for months or even years after planting.”]
  5. Douglas, M. R., et al., (2020). County-level analysis reveals a rapidly shifting landscape of insecticide hazard to honey bees (Apis mellifera) on US farmland. Scientific Reports, 10(1), 797, p. 6. [“Neonicotinoids accounted for the overwhelming majority of oral toxic load by 2012.” See also, Figure 5c for comparisons of “overall toxic load” showing neonics contribute the great majority in all agricultural regions of the U.S.]
  6. Bonmatin, J. M. et al., (2015). Environmental fate and exposure; neonicotinoids and fipronil. Environmental Science and Pollution Research International, 22(1), 35–67, p. 35. […the half-lives of neonicotinoids in soils can exceed 1,000 days, so they can accumulate when used repeatedly. Similarly, they can persist in woody plants for periods exceeding 1 year.”]
  7. Ospina, M., et al., (2019). Exposure to neonicotinoid insecticides in the US general population: Data from the 2015–2016 national health and nutrition examination survey. Environmental research, 176, 108555, p. 2. [“…half-lives varied from a few days to several years…”]
  8. Goulson, D. (2013). An overview of the environmental risks posed by neonicotinoid insecticides. The Journal of Applied Ecology, 50(4), 977–987, p. 978. [“The widespread adoption of neonicotinoids as seed dressings has led to a move away from integrated pest management (IPM), a philosophy of pest management predicated on minimizing use of chemical pesticides via monitoring of pest populations, making maximum use of biological and cultural controls, applying chemical pesticides only when needed and avoiding broad-spectrum, persistent compounds.”]
  9. Tooker, J. F. et al. (2017).

Neonics are:
More toxic.[1]
Persistent in the environment for longer periods.[2]
Much more widely applied than previously used insecticides.[3]
More pervasive in waterways.[4]
A product (coated seeds) that is regularly consumed by wildlife.[5]
Controlled by seed companies that encourage their widespread use, with limited input or oversight by farmers.[6]
To date, essentially untracked and unregulated by federal agencies.[7]

 

  1. DiBartolomeis, M., et al., (2019). An assessment of acute insecticide toxicity loading (AITL) of chemical pesticides used on agricultural land in the United States. PloS one, 14(8), e0220029, p. 22. [“The neonicotinoid insecticides, in particular imidacloprid, clothianidin, and thiamethoxam, are primarily responsible for this increased toxicity loading, accounting for 61 percent (via contact toxicity) to 99 percent (via oral toxicity) of the total toxicity loading of all insecticides in 2014.”]
  2. Bonmatin, J. M., et al., (2015). Environmental fate and exposure; neonicotinoids and fipronil. Environmental Science and Pollution Research International, 22(1), 35–67, p. 35. […the half-lives of neonicotinoids in soils can exceed 1,000 days, so they can accumulate when used repeatedly. Similarly, they can persist in woody plants for periods exceeding 1 year.”]
  3. Tooker, J. F., et al., (2017). Neonicotinoid Seed Treatments: Limitations and Compatibility with Integrated Pest Management. Agricultural & Environmental Letters, 2(1), 1–5, p. 4. [“Current use of (neonics)—on nearly 100% of corn acres and >50% of soybean acres—far exceeds historic benchmarks for insecticide use in these crops.”]
  4. Hladik, M. L., et al., (2014). Widespread occurrence of neonicotinoid insecticides in streams in a high corn and soybean producing region, USA. Environmental Pollution (1987), 193, 189–196, p. 195. [“Neonicotinoids were found more frequently and in higher concentrations than historically-used organophosphates and carbamates in previous investigations of similar landuse areas.”]
  5. Roy, C. L., et al., (2019). Multi-scale availability of neonicotinoid-treated seed for wildlife in an agricultural landscape during spring planting. Science of the Total Environment, 682, 271-281. p. 272. [“…ingestion of a single treated corn kernel is lethal to a blue-jay sized (~ 85 g) bird.”]
  6. Tooker, J. F., et al., (2017), p. 4. [“… many growers seem not to know they are using (neonics), probably because these insecticides are usually part of larger, standard packages of products applied by seed suppliers.”]
  7. Hitaj, C., et al., (2020). Sowing Uncertainty: What We Do and Don’t Know about the Planting of Pesticide-Treated Seed. Bioscience, 70(5), 390–403, pp., 390-391. [“The publicly available pesticide use data in the United States do not currently account for pesticides applied as seed treatments.” Researchers include USDA scientists.]

A 2021 USGS nationwide study of 17 pesticides found that imidacloprid (one of the 3 common neonics) “had the most widespread potential toxicity” and “posed the greatest potential threat to aquatic life.”[1]

A nationwide USGS study covering 24 states detected at least one neonic formulation in 63% of sampled streams.[2]

A report by USGS and EPA scientists found that the 3 most common neonics (clothianidin, thiamethoxam, and imidacloprid), “were found to be prevalent throughout the year in sampled tributaries to the Great Lakes, the largest freshwater ecosystem in the world.”[3]

Widespread neonic contamination of drinking water in agricultural areas has been documented.[4,5]

A CDC report estimated that in 2015 about half of Americans had neonics in their urine.[6]

Neonics are regularly detected at low levels in many foods, especially fruits and vegetables.[7,8]

 

  1. Stackpoole, S. M., et al., (2021). Pesticides in US rivers: regional differences in use, occurrence, and environmental toxicity, 2013 to 2017. Science of the Total Environment, 787, 147147. [“Imidacloprid posed the greatest potential threat to aquatic life with a total of 245 benchmark exceedances at 60 of the 74 sites.” See Highlights and Abstract]
  2. Hladik, M. L. & Kolpin, D. W. (2015). First national-scale reconnaissance of neonicotinoid insecticides in streams across the USA. Environmental Chemistry, 13(1), 12-20. Abstract [“Across all study areas, at least one neonicotinoid was detected in 63% of the 48 streams sampled.”]
  3. Hladik, M. L., et al., (2018). Year-round presence of neonicotinoid insecticides in tributaries to the Great Lakes, USA. Environmental pollution, 235, 1022-1029, p. 1028.
  4. Thompson, D. A., et al., (2023). Prevalence of neonicotinoid insecticides in paired private-well tap water and human urine samples in a region of intense agriculture overlying vulnerable aquifers in eastern Iowa. Chemosphere (Oxford), 319, 137904, Abstract. [“Human exposure was ubiquitous in urine samples.”]
  5. Klarich, K. L., et al., (2017). Occurrence of Neonicotinoid Insecticides in Finished Drinking Water and Fate during Drinking Water Treatment. Environmental Science & Technology Letters, 4(5), 168–173, Abstract. [“We report for the first time the presence of three neonicotinoids in finished drinking water and demonstrate their general persistence during conventional water treatment.”]
  6. Ospina, M., et al., (2019). Exposure to neonicotinoid insecticides in the US general population: Data from the 2015–2016 national health and nutrition examination survey. Environmental research, 176, 108555, p. 1. [“The weighted frequency of having detectable concentrations of at least one of the six biomarkers examined was 49.1%.”]
  7. Craddock, H. A., et al., (2019). Trends in neonicotinoid pesticide residues in food and water in the United States, 1999–2015. Environmental Health, 18, 1-16, p. 4. [Neonics detected on more than 20% of samples: apple commodities, cherries, pears, strawberries, cauliflower, celery, cherries, cilantro, grapes, greens-collard, greens-kale, lettuce, potatoes, and spinach.]
  8. Olga V. Naidenko, Ph.D., VP, Science Investigations and Alexis M. Temkin, Ph.D., Toxicologist (March 15, 2023) Three neonic pesticides banned in Europe are common on U.S. produces. https://www.ewg.org/foodnews/neonic-pesticides.php

Yes. The damaging effects of neonics on a range of species are persistent, widespread, and well documented.[1-4]

 

  1. Bonmatin, J. M., et al., (2015). Environmental fate and exposure; neonicotinoids and fipronil. Environmental Science and Pollution Research International, 22(1), 35–67, p. 35. [“…measurements taken from water have been found to exceed ecotoxicological limits on a regular basis around the globe. The presence of these compounds in the environment suggests that all kinds of nontarget organisms will be exposed to them.”]
  2. Goulson, D. (2013). An overview of the environmental risks posed by neonicotinoid insecticides. The Journal of Applied Ecology, 50(4), 977–987, pp. 984-985. [“…UK indices for bees, butterflies, moths, carabid beetles and birds… all show significant overall declines in recent years…. The evidence presented here suggests that the annually increasing use of neonicotinoids may be playing a role in driving these declines.”]
  3. Mamy, L., et al., (2023). Impacts of neonicotinoids on biodiversity: a critical review. Environmental Science and Pollution Research, 1-36. [“…this review showed that these substances have particularly high direct and indirect impacts on terrestrial invertebrates and vertebrates, and on aquatic invertebrates.”]
  4. U.S. EPA (May 1, 2023) Imidacloprid, Thiamethoxam and Clothianidin: Draft Predictions of Likelihood of Jeopardy and Adverse Modification for Federally Listed Endangered and Threatened Species and Designated Critical Habitats, pp. 5-10 and tables E1-E3. [For example, imidacloprid “is classified as very highly toxic to aquatic invertebrates.” “For terrestrial organisms, imidacloprid is characterized as highly toxic to bees, highly toxic to birds and moderately toxic to mammals.” Likelihood of jeopardy: Imidacloprid (199 species); Thiamethoxam (204 species); Clothianidin (166 species)]

Neonics are understood to be highly damaging to:
Bees and many other pollinators.[1-3]
A wide range of non-target insects, especially aquatic species.[4,5]
Birds, especially insectivores.[6,7]

Although neonics are assumed to be less toxic to vertebrate wildlife, there is evidence that mammals and fish are often impacted directly, either by the consumption of seeds or by eating contaminated prey, or indirectly by damage to their food webs.[8-10]

 

  1. Rundlöf, M. et al., (2015). Seed coating with a neonicotinoid insecticide negatively affects wild bees. Nature (London), 521(7550), 77–80.
  2. Sánchez-Bayo, F., et al., (2016). Are bee diseases linked to pesticides? A brief review. Environment international, 89, 7-11, p. 10. [“Therefore, neonicotinoids and interacting pesticides (e.g. EIFs) are important stress factors underpinning colony health decline and eventual collapse, significantly contributing to the spread and abundance of pathogens and parasites, which are the proximate mortality factors.”]
  3. Van der Sluijs, J. P., et al., (2013). Neonicotinoids, bee disorders and the sustainability of pollinator services. Current opinion in environmental sustainability, 5(3-4), 293-305. p. 293. [“The limited available data suggest that they are likely to exhibit similar toxicity to virtually all other wild insect pollinators.” Pollinators include bees, wasps, birds, butterflies, moths, and flies.]
  4. Sánchez-Bayo, F. et al. (2016). Contamination of the Aquatic Environment with Neonicotinoids and its Implication for Ecosystems. Frontiers in Environmental Science, 4, p. 10. [“The decline of many populations of invertebrates, due mostly to the widespread presence of water borne residues and the extreme chronic toxicity of neonicotinoids, is affecting the structure and function of aquatic ecosystems.”]
  5. Barmentlo, S. H., et al., (2021). Experimental evidence for neonicotinoid driven decline in aquatic emerging insects. PNAS, 118(44), e2105692118. p. 1. [“We show that increasing neonicotinoid concentrations strongly decreased the abundance and biomass of five major insect orders that together comprised >99% of the 55,574 collected insects as well as the diversity of the most species-rich freshwater family, thus showing a causal relation between insect decline and neonicotinoids.”]
  6. Molenaar, E., et al., (2024). Neonicotinoids Impact All Aspects of Bird Life: A Meta‐Analysis. Ecology Letters, 27(10), e14534, Abstract. [“…we use a meta-analytical approach synthesising 1612 effect sizes from 49 studies and show that neonicotinoids consistently harm bird health, behaviour, reproduction, and survival.”]
  7. Li, Y., et al., (2020). Neonicotinoids and decline in bird biodiversity in the United States. Nature Sustainability, 3(12), 1027–1035.
  8. Gibbons, D., et al., (2015). A review of the direct and indirect effects of neonicotinoids and fipronil on vertebrate wildlife. Environmental Science and Pollution Research, 22, 103-118. [“Evidence presented here suggests that the systemic insecticides, neonicotinoids and fipronil, are capable of exerting direct and indirect effects on terrestrial and aquatic vertebrate wildlife…”]
  9. Goulson, D. (2013). An overview of the environmental risks posed by neonicotinoid insecticides. The Journal of Applied Ecology, 50(4), 977–987, p. 983. [“Although vertebrates are less susceptible than arthropods, consumption of small numbers of dressed seeds offers a route to direct mortality in birds and mammals…With typical sowing rates… we might expect sufficient seed to be available on the soil surface to deliver an LD50 to 100 partridge or 167 mice for every hectare sown.” LD50 is the dose at which 50% of the animals are expected to die.]
  10. Yamamuro, M., et al., (2019). Neonicotinoids disrupt aquatic food webs and decrease fishery yields. Science (American Association for the Advancement of Science), 366(6465), 620–623.

In the U.S. 37% of bee species are at risk of extinction.[1] The widespread use of neonics is understood to be a central factor in bee colony health decline and collapse.[2] Neonic seed coatings negatively affect the density of bees, along with their nesting, colony growth, and reproduction.[3,4]

In 2023, the EPA noted that the 3 most common neonics are “highly toxic to bees on an acute exposure basis.” And that, “Available data suggest potential effects to honeybee and bumble bee colonies that manifest as impacts to numbers of adults and decreases in brood.”[5]

 

  1. NatureServe (2023) Biodiversity in Focus: United States Edition. NatureServe: Arlington, VA, p. 10, Figure 2.
  2. Sánchez-Bayo, F., et al., (2016). Are bee diseases linked to pesticides? A brief review. Environment international, 89, 7-11, p. 10. [“Therefore, neonicotinoids and interacting pesticides (e.g. EIFs) are important stress factors underpinning colony health decline and eventual collapse, significantly contributing to the spread and abundance of pathogens and parasites, which are the proximate mortality factors.”]
  3. Rundlöf, M. et al., (2015). Seed coating with a neonicotinoid insecticide negatively affects wild bees. Nature (London), 521(7550), 77–80, p. 78. 
  4. Xerces Society for Invertebrate Conservation IPI Database, Neonicotinoids. https://www.pesticideimpacts.org/neonicotinoids [This database has an extensive, though dated, listing of scientific reports documenting the impacts to bees.]
  5. U.S. EPA (May 1, 2023) Imidacloprid, Thiamethoxam and Clothianidin: Draft Predictions of Likelihood of Jeopardy and Adverse Modification for Federally Listed Endangered and Threatened Species and Designated Critical Habitats, pp. 5-6.

Butterflies: A recent report documented a 22% decline in total butterfly abundance in the last two decades.[1] Neonics are a leading cause, with monarch butterflies severely affected.[2] Butterflies, like bees, are pollinators.

Birds: The decline in bird biodiversity has been directly linked to neonics.[3] Birds are harmed by eating seeds or contaminated plant material, by the decrease in insect food supply, and by residues in their food and water.[4] The ingestion of deadly neonic-treated seeds is common, calculable, and expected, given the huge numbers of planted seeds and normal spillage rates.[5] A single treated corn kernel is lethal to a blue-jay sized bird. A detailed non-profit report documents the impacts of neonics on birds and other wildlife, calling out the damage as “a predictable environmental disaster.”[6]

Aquatic life: In the U.S., freshwater species have the highest number of at-risk species.[7] Reports have identified significant lethal and sublethal effects of neonics on both aquatic insects and invertebrates that feed on them.[8,9] “The decline of many populations of invertebrates, due mostly to the widespread presence of waterborne residues and the extreme chronic toxicity of neonicotinoids, is affecting the structure and function of aquatic ecosystems. Consequently, invertebrates that depend on insects and other aquatic invertebrates as their sole or main food resource are being affected.”[10]

 

  1. Edwards, C.B., et al., (2025) Rapid butterfly declines across the United States during the 21st century. Science 387, 1090-1094, p. 4 [“Insecticides have been identified as leading causes of butterfly declines in recent analyses in the midwestern US and California.”]
  2. Van Deynze, B., et al., (2024). Insecticides, more than herbicides, land use, and climate, are associated with declines in butterfly species richness and abundance in the American Midwest. Plos one, 19(6), e0304319. p. 1 and p. 11 Figure 3. [“We find community-wide declines in total butterfly abundance and species richness to be most strongly associated with insecticides in general, and for butterfly species richness the use of neonicotinoid-treated seeds in particular.”]
  3. Li, Y., et al., (2020). Neonicotinoids and decline in bird biodiversity in the United States. Nature Sustainability, 3(12), 1027, p. 1032, Abstract. [“…the increase in neonicotinoid use led to statistically significant reductions in bird biodiversity between 2008 and 2014 relative to a counterfactual without neonicotinoid use, particularly for grassland and insectivorous birds, with average annual rates of reduction of 4% and 3%, respectively.”] 
  4. Molenaar, E., et al., (2024). Neonicotinoids Impact All Aspects of Bird Life: A Meta‐Analysis. Ecology Letters, 27(10), e14534-n/a, p. 2. [“…population declines are also common in a number of granivorous, frugivorous, and carnivorous bird species. This suggests that neonicotinoids may—despite initial arguments against this possibility— directly affect the health of birds exposed to polluted food, water, air, or soil, thereby impacting their behaviour, reproduction, and survival, and thus, ultimately, population persistence regardless of diet…”]
  5. Roy, C. L., et al., (2019). Multi-scale availability of neonicotinoid-treated seed for wildlife in an agricultural landscape during spring planting. Science of the Total Environment, 682, 271-281. p. 272 [“…ingestion of a single treated corn kernel is lethal to a blue-jay sized (~ 85 g) bird.”]
  6.  Pierre Mineau & Hardy Kern (2023) Neonicotinoid insecticides: Failing to come to grips with a predictable environmental disaster, American Bird Conservancy, https://abcbirds.org/wp-content/uploads/2023/07/2023-Neonic-Report.pdf
  7. NatureServe (2023) Biodiversity in Focus: United States Edition, p. 11. [“As a group, species associated with fresh water, including amphibians, snails, mussels, crayfish, and many aquatic insects, have the highest percentage of at-risk species, highlighting the importance of conservation strategies to protect freshwater ecosystems.”]
  8. Mandal, A. H., et al., (2025). Evaluating the impact of neonicotinoids on aquatic non-target species: A comprehensive review. Environmental Toxicology and Pharmacology, 113, 104606, Abstract. [“However, due to their water solubility, mobility, and moderate persistence, NNIs easily contaminate adjacent aquatic environments via runoff, leaching, or spray drift. While less toxic to vertebrates, their widespread use poses threats to aquatic and terrestrial organisms, causing neurotoxicity, nephrotoxicity, cytotoxicity, genotoxicity, immunotoxicity, hepatotoxicity, endocrine disruption, and reproductive malformations.”]
  9. Morrissey, C. A., et al., (2015) Neonicotinoid contamination of global surface waters and associated risk to aquatic invertebrates: A review. Environment International, 74, 291–303, p. 295.
  10. Sánchez-Bayo, F. et al. (2016). Contamination of the Aquatic Environment with Neonicotinoids and its Implication for Ecosystems. Frontiers in Environmental Science, 4, p. 10.

Since most neonics are applied to corn and soybean crops, those agricultural areas are associated with unusually high levels of accumulated toxicity and therefore the greatest threats to biodiversity.[1,2]

Regional studies show higher risks for bee populations in areas with expanding corn and soybean crops.[3,4] Similarly, declines in bird populations and diversity are especially prevalent in areas growing corn and soybeans.[5,6]

 

  1. DiBartolomeis, M., et al., (2019). An assessment of acute insecticide toxicity loading (AITL) of chemical pesticides used on agricultural land in the United States. PloS one, 14(8), e0220029, p. 22. [“The crops most responsible for the increase in AITL (Acute Insecticide Toxicity Loading) are corn and soybeans.”]
  2. Douglas, M. R., et al., (2020). County-level analysis reveals a rapidly shifting landscape of insecticide hazard to honey bees (Apis mellifera) on US farmland. Scientific Reports, 10(1), 797–11, p. 6. [“We found that the increase in oral toxic load was particularly acute in the Heartland and Northern Great Plains regions, which showed a 121-fold and 53-fold increase, respectively. We attribute this pattern to the increasing use of neonicotinoid seed treatments in corn and soybean.”]
  3. Krupke, C. H., et al., (2017). Planting of neonicotinoid-treated maize poses risks for honey bees and other non-target organisms over a wide area without consistent crop yield benefit. The Journal of Applied Ecology, 54(5), 1449–1458, p. 1449. [“Our results indicate that over 94% of honey bee foragers throughout the state of Indiana are at risk of exposure to varying levels of neonicotinoid insecticides, including lethal levels, during sowing of maize.”]
  4. Sánchez-Bayo, F. & Wyckhuys, K. A. G. (2019). Worldwide decline of the entomofauna: A review of its drivers. Biological Conservation, 232, 8–27, p. 12. [“Wild bees were declining in 23% of the country between 2008 and 2013, mainly in the Midwest, Great Plains and the Mississippi valley, where grain production – particularly corn for biofuels production – has almost doubled during that period.”]
  5. Li, Y., et al., (2020). Neonicotinoids and decline in bird biodiversity in the United States. Nature Sustainability, 3(12), 1027, p. 1030. [“Our finding of the effects of land cover on species richness is comparable to some previous results that also show that a 1% increase in high-input but low-diversity crops (corn and soybeans) in the Midwest contributes to a decline of 0.55% to 0.77% in total avian species richness.”]
  6. van der Burg, M. P., et al., (2023). Trending against the grain: Bird population responses to expanding energy portfolios in the US Northern Great Plains, U.S. Geological Survey, Ecological Applications, 33(7), e2904, p. 10. [“Our analysis showed that grassland birds responded more negatively to biofuel feedstocks (i.e., corn and soybeans) on the landscape compared with oil and gas development.”]

No, not the seed treatments. Pesticide-treated seeds are currently exempt from pesticide registration requirements under federal law. The EPA has maintained that, because it has already assessed neonicotinoid chemicals, no new assessment or risk finding is necessary for the treated article (the seeds). This is known as the Treated Article Exemption.[1]

“In a nutshell, this means that the EPA does not regulate, track, or report on the use of treated seeds as it does other pesticides.”[2]

States may impose different regulations. For instance, New York became the first state to pass legislation restricting the use of neonic seeds (taking effect 2029).[3]

 

  1. 88 Fed Reg. 70625, 70627 (October 2023) Pesticides; Review of Requirements Applicable to Treated Seed and Treated Paint Products; Request for Information and Comments. [“It has been EPA’s longstanding position that FIFRA section 25(b)(2) authorized the 1988 final rule exempting pesticide-treated articles or substances because EPA’s assessment of the treating pesticide comprehensively addresses the use of and exposure to the treating pesticide and to the article or substance that is permissibly treated.”]
  2. Rosemary Malfi (November 2023) Tell the EPA: Overuse of Pesticide-Treated Seed is a Threat to Waterways and Wildlife. Xerces Society https://www.xerces.org/blog/EPA-comments-treated-seed
  3. Bio.News (January 2024) New York passes law restricting use of neonicotinoids in seeds. https://bio.news/agriculture/new-york-law-neonicotinoids-neonic-treated-seeds/ [ “The law would make it illegal to use neonicotinoid pesticide (neonics) treated seeds for corn, soybean, or wheat as of 2029 without a waiver. To continue using neonic-treated seeds after the 2029 planting season, farmers will need to present an evaluation showing that their fields are under threat from pests. They would also be required to take integrated pest management training.”]

In 2023 the EPA completed “draft predictions” for neonics that documented many threats to those species currently listed as endangered under the Endangered Species Act.[1] As of April 2025, the agency’s website indicates that it plans to review and possibly amend registrations for these insecticides in 2025.[2]

It has taken lawsuits by the NRDC and Center for Food Safety to prompt the EPA’s actions.[3] The long history of the EPA’s wholly ineffective response to a “predictable environmental disaster” has been well documented.[4]

An important step beyond a proper assessment of the toxicity to species would be to re-classify neonic-treated seeds as “pesticides,” since the majority of neonics are applied as seed treatments.[5] Currently, neither the EPA nor the USDA tracks the amount of neonics used as seed treatments (see above question). And as one researcher with over 40 years of experience assessing the environmental risk of pesticides asks, if the EPA does not “quantitatively account for most of that pesticide’s use, how can it possibly arrive at the correct conclusions?”[6]

The European Union has almost completely banned the use of neonics since 2018.[7]

 

  1. U.S. EPA (May 1, 2023) Imidacloprid, Thiamethoxam and Clothianidin: Draft Predictions of Likelihood of Jeopardy and Adverse Modification for Federally Listed Endangered and Threatened Species and Designated Critical Habitats, p. 5. [“The purpose of this assessment is to assess effects at the population level and then make predictions whether there is a likelihood that the neonicotinoid insecticides imidacloprid, thiamethoxam and clothianidin registrations have the potential to lead to jeopardy of federally listed endangered and threatened (“listed”) or adverse modification of designated critical habitat.”] 
  2. U.S. EPA (July 26, 2024) Schedule for Review of Neonicotinoid Pesticides. https://www.epa.gov/pollinator-protection/schedule-review-neonicotinoid-pesticides
  3. see, National Resources Defense Council (January 28, 2021) Court Settlement: EPA Must Evaluate Impacts of Harmful Pesticide on Imperiled Species, and Center for Food Safety (December 15, 2021) EPA Sued Over Failure to Close Pesticide-Coated Seed Loophole Killing Bees and Endangered Species.
  4. Pierre Mineau & Hardy Kern (2023) Neonicotinoid insecticides: Failing to come to grips with a predictable environmental disaster, American Bird Conservancy.
  5. Douglas, M. R., & Tooker, J. F. (2015). Large-Scale Deployment of Seed Treatments Has Driven Rapid Increase in Use of Neonicotinoid Insecticides and Preemptive Pest Management in U.S. Field Crops. Environmental Science & Technology, 49(8), 5088–5097, p. 5092.
  6. Pierre Mineau & Hardy Kern (2023), p. 8.
  7. European Commission on Food Safety, Neonicotinoids. https://food.ec.europa.eu/plants/pesticides/approval-active-substances/renewal-approval/neonicotinoids_en

Drivers of Biodiversity Loss