[9][11][12] A 2018 review by the European Food Safety Authority (EFSA) concluded that most uses of neonicotinoid pesticides represent a risk to wild bees and honeybees.
[11][13] In 2022 the United States Environmental Protection Agency (EPA) concluded that neonicotinoids are likely to adversely affect the majority of federally listed endangered or threatened species and of critical habitats.
As of 2013[update] neonicotinoids were used in the U.S. on about 95 percent of corn and canola crops, the majority of cotton, sorghum, and sugar beets and about half of all soybeans.
They have been used on the vast majority of fruit and vegetables, including apples, cherries, peaches, oranges, berries, leafy greens, tomatoes, and potatoes, to cereal grains, rice, nuts, and wine grapes.
[38][39][40] Neonicotinoid seed treatments can protect yield in individual cases such as late-planted fields or in areas with large infestations much earlier in the growing season.
To best take advantage of new research as it becomes available, the EPA moved ahead the docket openings for the remaining neonicotinoids on the registration review schedule (acetamiprid, clothianidin, dinotefuran, thiacloprid, and thiamethoxam) to FY 2012.
The Act called for the suspension of the use of four neonicotinoids, including the three recently suspended by the European Union, until their review is complete, and for a joint Interior Department and EPA study of bee populations and the possible reasons for their decline.
[53] In 2014, under the Obama administration, a blanket ban was issued against the use of neonicotinoids on National Wildlife Refuges in response to concerns about off-target effects of the pesticide, and a lawsuit from environmental groups.
[56] In 2008, Germany revoked the registration of clothianidin for use on seed corn after an incident that resulted in the death of millions of nearby honey bees.
The study was published in January 2013, stating that neonicotinoids pose an unacceptably high risk to bees and that the industry-sponsored science upon which regulatory agencies' claims of safety have relied may be flawed and contain data gaps not previously considered.
Their review concluded, "A high acute risk to honey bees was identified from exposure via dust drift for the seed treatment uses in maize, rapeseed, and cereals.
[68] In Switzerland, where neonicotinoids were never used in alpine areas, neonics were banned because of accidental poisonings of bee populations and the relatively low safety margin for other beneficial insects.
[69] Environmentalists called the move "a significant victory for common sense and our beleaguered bee populations" and said it is "crystal clear that there is overwhelming scientific, political, and public support for a ban.
In March 2017, The Guardian printed an article that claimed that they had obtained information that indicated that the European Commission wanted a complete ban and cited "high acute risks to bees".
[70][71][72] On 27 April 2018, member states of the European Union agreed upon a total ban on neonicotinoid insecticide use, except within closed greenhouses, to be imposed from the end of 2018.
[75] The vote on the proposed ban followed a February 2018 report from the European Food Safety Authority which concluded that neonicotinoids posed a high risk to both domestic and wild bees.
The report looked at the short- and medium-term impacts of a complete ban of all neonicotinoids on agricultural and total value added (VA) and employment, global prices, land use, and greenhouse gas (GHG) emissions.
[82] On 10 December 2015, Montreal banned all neonicotinoids – without exception – on all properties within the city limits, including the Botanical Garden, all agricultural areas, and all golf courses.
[95][96] Many biological factors influence colony collapse disorder, including varroa mite infestation and Israeli acute paralysis virus (IAPV).
[100] In 2017, researchers demonstrated the combined effects of nutritional stress and low doses of common, widely used neonicotinoid pesticides (clothianidin, thiamethoxam) found in nectar and pollen.
[101] Declines in managed and wild bee populations have been attributed, in part, to the combination of direct and indirect effects of neonicotinoids that render them vulnerable to pathogens.
[8] Research suggests potential toxicity to honey bees and other beneficial insects even with low levels of exposure, with sublethal effects that negatively impact the survival of colonies.
In lab studies, neonicotinoids were shown to increase mortality rates[103] and negatively affect the ability to fly[104] and forage in exposed bees.
[103][100] Studies have shown a variety of sublethal effects of neonicotinoids on bumblebees, including lower reproduction rates, production of fewer workers and queens, and numerous behavioral changes.
[9] In April 2015 EASAC conducted a study of the potential effects on organisms providing a range of ecosystem services like pollination and natural pest control which are critical to sustainable agriculture.
The resulting report concludes "there is an increasing body of evidence that the widespread prophylactic use of neonicotinoids has severe negative effects on non-target organisms that provide ecosystem services including pollination and natural pest control.
[109] A 2017 survey covering every continent with honeybees found neonicotinoids in three-fourths of honey samples, albeit in every case at levels considered safe for human consumption.
[114] There have been reports of developmental abnormalities and reduced eggshell thickness, fertilization success, and embryo size with direct exposure to pesticides including neonicotinoids.
[118] A 2014 observational study conducted in the Netherlands correlated declines in some bird populations with environmental imidacloprid residues, although it stopped short of concluding that the association was causal.
[9] Rodents exposed chronically or acutely to neonicotinoids suffer major damage to their nervous systems, likely due to impairment of their neurotransmitter mechanisms.