Bees and Neonicotinoids

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There is growing global alarm over declining populations of honey bees and other pollinators. While it is uncertain whether these declines constitute a "pollinator crisis," they cannot be taken lightly. Pollinators are integral to our environmental and socio-economic welfare, and their loss would be nothing short of catastrophic.

In Ontario, most fruits, vegetables, forages (e.g., alfalfa, clover) and oilseeds (e.g., canola, sunflower) rely on animal pollination. Globally, pollinators are involved in an estimated 35 per cent of food production, and 87 of the world’s major food crops depend on pollinators to some extent. Over the last half century, pollinator-dependent agricultural production has increased by more than 300 per cent, and the total economic value of pollination in agricultural production has been estimated at $213 billion.

Pollinators of all kinds – not just honey bees – play a vital role in maintaining biodiversity and ecosystem stability. Wild pollinators, including bees and other invertebrates (e.g., moths, flies, wasps, beetles, butterflies), as well as vertebrate pollinators (e.g., bats, birds), have a key function in the fertilization of both crops and non-crop flowering plants. By one estimate, 87.5 per cent of the world’s flowering plants rely on pollinators for reproduction. Losing a species within a pollination network may trigger further reductions in biodiversity that cascade throughout the food chain.

Pollinator Populations are Declining

In recent years, substantial abnormal declines in honey bee (Apis mellifera) populations have been observed, notably in North America and Europe. These observations include above-average colony losses in Ontario: over the last eight years, the average overwintering loss of bee colonies in Ontario has been approximately 34 per cent – more than double the 15 per cent winter loss rate that is considered to be acceptable by apiculturists (see Figure 2.2.1).

Figure 2.2.1 Overwintering bee losses in Ontario and Canada.JPG

In addition to these overwintering losses, a number of other large-scale bee deaths have been reported in Canada in recent years. In the spring and summer of 2012 and 2013, Canada’s Pest Management Regulatory Agency (PMRA) received numerous reports of honey bee mortalities from beekeepers in Ontario, Quebec and Manitoba.

Assessment of the health and abundance of wild pollinator populations is hampered by an absence of monitoring and data collection. However, evidence is emerging that many wild pollinators, particularly bumble bees, are in decline. The Committee on the Status of Pollinators in North America has stated that long-term population trends are demonstrably tipping downward for several wild bee species, as well as for some butterflies, bats and hummingbirds. Evidence of declines among insectivorous birds may also suggest broader negative trends in insect populations.

A number of factors are believed to be at play in driving pollinator declines, including pathogens, parasites, agrochemicals, habitat degradation and loss, decreased resource diversity, climate change and invasive species. Researchers have determined that honey bee losses are likely the result of several of these factors interacting to make colonies more susceptible to disease.

Lately, however, the role of pesticides in pollinator decline is receiving increasing attention. The ECO first highlighted the emerging connection between pollinator declines and pesticide use in Part 4.6 of our 2008/2009 Annual Report. In recent years, particular scrutiny has fallen on a class of pesticides called neonicotinoids.

Growing Concern about Neonicotinoids

Neonicotinoids are a class of insecticides that includes such products as imidacloprid, clothianidin, thiamethoxam, thiacloprid and acetamiprid. The use of neonicotinoids has increased significantly since their introduction in the 1990s. They are now the most widely used insecticides in the world, representing more than a quarter of the global market share. In Ontario, neonicotinoids are registered (i.e., permitted) for use on all field crops except forages, and are frequently used on corn, canola, dry beans and soybeans.

Neonicotinoids act systemically, meaning that they diffuse throughout the tissues and sap of treated plants, and are found in pollen, nectar and guttation droplets (i.e., small drops of liquid exuded by some plants). They are most commonly used as seed treatments, although they may be applied in other ways, such as foliar sprays and soil additions. Pollinators are primarily exposed to neonicotinoids through nectar, pollen and, notably, contaminated dust generated during the planting of treated seeds. Pollinators may also transport pollen or other materials containing neonicotinoids back to the hive, allowing for continued exposure.

These pesticides act as neurotoxins in the insect nervous system and are toxic in very small quantities relative to other types of pesticides. Exposure to neonicotinoids has been linked to both lethal and sublethal effects on pollinators. For example, there is now clear evidence that acute exposure to neonicotinoid-contaminated dust is linked to mass bee deaths observed during the planting of seed-treated crops. The PMRA’s investigation into the 2012 and 2013 bee kills in Canada concluded that neonicotinoids were a contributing factor in many cases. Accordingly, in 2013, the PMRA declared that “current agricultural practices related to the use of neonicotinoid-treated corn and soybean seed are not sustainable.”

A number of studies have also concluded that neonicotinoids can cause adverse sublethal effects on honey and bumble bees, such as: impaired memory and learning; interference with orientation, homing, mobility and other foraging behaviours; reduced development, reproduction and queen production; and impaired immune function and increased susceptibility to pathogens. However, further research is needed to ascertain whether these effects are expected at the exposure concentrations that are experienced by pollinators in the field. Even with lower concentrations, cumulative and/or synergistic effects may cause impaired colony function or even failure. For example, one recent study concluded that chronic sublethal stress can be a cause of honey bee colony failure, noting that if many bees in a colony become impaired, it may lead to a cumulative effect on normal colony function.

While the impact of neonicotinoids on bees has received a great deal of attention, honey bee declines may be a warning sign of a larger ecological problem. Troubling questions are being raised about the broader environmental effects of these pesticides. Only a small portion of the active substance is taken up by plants in seed-treated crops, and the rest enters the environment. This is of concern because neonicotinoids are not only persistent in soil and water, but are also water soluble and highly mobile within ecosystems.

As a result, neonicotinoids may accumulate in soil, potentially having adverse effects on soil ecosystems and creating a likelihood of uptake by subsequently planted crops and wild plants. They may also migrate into ground and surface water. Runoff and spray drift can have an impact on aquatic invertebrates in streams and ponds. In one California study, imidacloprid was detected in 89 per cent of surface water samples – with 19 per cent of samples exceeding aquatic invertebrate toxicity guidelines. A recent study in the Netherlands demonstrated that aquatic macro-invertebrates are less abundant in surface water with higher imidacloprid concentrations, suggesting potential consequences for the food chain and ecosystem functions. Finally, neonicotinoids can pose serious risks to birds and mammals that consume treated seeds.

Action to Protect Pollinators from Neonicotinoids

In September 2013, the PMRA issued a Notice of Intent that outlined a series of proposed federal actions in response to the agency’s determination that the current neonicotinoid practices are not sustainable. The PMRA announced that for the 2014 planting season, it would implement additional protective measures, such as: requiring the use of dust-reducing seed flow lubricants; setting safer seed planting practices; and placing warnings on pesticide and seed package labels. It will also require industry to provide additional information to support the position that continued neonicotinoid treatment is necessary on up to 100 per cent of corn and 50 per cent of soybean seed. The PMRA is in the process of re-evaluating three neonicotinoid insecticides (clothianidin, thiamethoxam and imidacloprid), and states that it will take action if there are reasonable grounds to believe that the health and environmental risks are unacceptable. An interim report is expected by 2015.

Ontario has started to take note of this issue as well. In March 2013, the Ministry of Agriculture and Food (OMAF) issued a document that included a series of suggested best practices to help reduce the risk of bee kills when planting (e.g., limiting the amount of seed lubricant used, altering the timing of planting, etc.). The ministry document also stated that “it is time to get back to integrated pest management” (see box, "What is Integrated Pest Management?").

In March 2014, OMAF released detailed direction on the use of planter deflectors to mitigate dust drift.

What is Integrated Pest Management?
Integrated pest management (IPM) is an ecological approach to pest control that uses a variety of management measures to prevent economic loss. The foundation of IPM is the identification and ongoing monitoring of pests and beneficial species.

IPM emphasizes preventing pests from becoming a threat through cultural control methods, including crop rotation, the selection of proper planting sites, and the cultivation of pest resistant crop varieties. If monitoring reveals that preventative measures are ineffective and pest populations reach a threshold at which they become an economic threat, then a variety of additional management options can be undertaken, including biological, mechanical and chemical controls. Control techniques with high environmental impact, such as the wide application of non-specific pesticides, are only employed as a last resort.

Ultimately, IPM encourages the more efficient use of agrochemicals and other inputs – which maintains economic returns – while minimizing the adverse effects of pesticide use.

In July 2013, the Ontario government announced that it would be establishing a Bee Health Working Group with a mandate to develop and support strategies to mitigate the risk of exposure to neonicotinoid seed treatments on corn and soybeans. The group’s report was released in March 2014, and included a series of 13 “options for action,” along with benefits and considerations. The options identified by the working group are primarily focused on improvements to growing practices, technical options to reduce the production of and exposure to contaminated dust, and improved training for users of seed treated crops. The report’s recommendations also include developing a strategy on pollinator friendly habitats. The working group’s report states that some members of the group endorsed a temporary ban on the use of neonicotinoids, noting that this course of action would be consistent with the precautionary approach and action taken by other jurisdictions. However, OMAF stated that it would “continue to look to the federal government, the regulator of pesticides in Canada, to provide evidence-based direction on a national approach to neonicotinoid use.”

Following the release of the working group’s report, the Ontario government stated that it is addressing pollinator health issues through a range of actions, including committing more than $1.2 million to research bee health and best management practices in field crop production, and establishing a new Ontario Pollinator Health Working Group to address concerns regarding all pollinators in the province.

Other jurisdictions are taking more aggressive action on neonicotinoids. Following earlier restrictions on neonicotinoids in Germany, France, Italy and Slovenia, the European Union adopted a proposal to restrict certain uses of clothianidin, imidacloprid and thiamethoxam for a period of two years beginning December 1, 2013. This decision was made in response to a report by the European Food Safety Authority, which identified a number of “high acute risks” for bees with respect to the three pesticides.

In the United States, legislation has been introduced in Congress that would suspend the registrations of neonicotinoids and ban new registrations of any pesticide for use on bee- attractive plants until the U.S. Environmental Protection Agency determines that the insecticide will not cause “unreasonable adverse effects” on pollinators, including native bees, honey bees, and other beneficial insects, as well as birds and bats. The proposed law would require a monitoring program for native bees, with annual reporting obligations. In addition, in August 2013, the U.S. Environmental Protection Agency announced new labelling requirements for neonicotinoids, including a bee advisory that prohibits use of some neonicotinoid pesticides where bees are present.

The Regulation of Pesticides in Ontario
Pesticides are regulated by both the federal and provincial governments. Pesticides are registered federally under the Pest Control Products Act (PCPA) after being evaluated by the Pest Management Regulatory Agency (PMRA) of Health Canada, which assesses possible health and environmental effects. As is the case with several neonicotinoids, the PMRA may grant conditional registration of pesticides (allowing the pesticide to be used for a limited period of time), with the potential for full registration once additional data requirements are met.

The Ontario government classifies federally registered pesticides for sale and use in the province. Ontario is able to regulate the sale, use, storage, transportation and disposal of pesticides under the Pesticides Act and O. Reg. 63/09. The Ontario government has the ability to prohibit the use of a registered pesticide within the province or impose more restrictive conditions on the use of the product than those under the PCPA. For example, in 2009, Ontario enacted a ban on the sale and use of pesticides for cosmetic purposes (see Part 4.6 of our 2008/2009 Annual Report).


The ECO is encouraged that the Ontario government is recognizing the importance of pollinators and the serious nature of the threats they face. Recognition of the problem, however, is only the beginning. The Ontario government needs to take swift action and commit dedicated resources in order to avert a potential ecological and economic crisis. The steps taken today to protect pollinators will determine the state of our biodiversity and food security for years to come.

There is now abundant evidence linking bee kills to neonicotinoid-contaminated dust generated during the planting of seed-treated crops. The ECO is hopeful that the federal government’s new dust mitigation requirements that apply to the use of neonicotinoid-treated seed will be effective. However, if these measures prove to be insufficient, restrictions on seed treatment with neonicotinoids should be considered by the Ontario government for the 2015 planting season.

The Ontario government’s commitment of funds for research on bee health is commendable. However, the government should clarify whether it will provide ongoing funding, and it should publicly articulate its research priorities. In particular, further research is needed with respect to the risks posed to all pollinators by field-realistic exposure levels of neonicotinoids.

While these first steps are encouraging, the Ontario government’s relatively narrow focus on pollinators fails to address the broader effects of neonicotinoids in the environment. Questions about the wide-ranging ecosystem impacts of neonicotinoids warrant immediate attention. The ECO strongly urges OMAF and the Ministry of the Environment to undertake environmental monitoring to determine the prevalence and effects of neonicotinoids in soil, waterways and wild plants.

The ECO commends OMAF for acknowledging the importance of protecting all pollinators in the province. There is a pressing need for monitoring wild pollinators, such as butterflies, moths, wild bees and bats. Without this knowledge the Ontario government will not have the ability to recognize, let alone prevent or mitigate, a pollinator crisis. The ECO urges OMAF and the Ministry of Natural Resources to commit to a broad-scale monitoring program for wild pollinators, and ensure adequate funding. Such a program could also be implemented as a component of a larger provincial biodiversity monitoring initiative; the ECO has repeatedly advocated for the government to undertake biodiversity monitoring (see Part 4.1 of the ECO’s 2012/2013 Annual Report). This work is also an important component in meeting Canada’s commitment to the international Aichi Biodiversity Targets, which are to be achieved by 2020. The ECO also reminds the government that any future strategy for pollinator health should be posted on the Environmental Registry for public notice and consultation, as this would clearly constitute an environmentally significant policy.

Although reducing exposure to neonicotinoids presents an immediate challenge, fully protecting our pollinators requires a more comprehensive and long-term approach that accounts for the influence of additional contributing factors, such as habitat loss, nutrition, pathogens, exposure to other agrochemicals, etc. Focused research, along with ongoing monitoring of pollinator populations, should provide the baseline data necessary to develop an effective action plan. Since agricultural management practices are bound to be a crucial element of such a strategy, the ECO is encouraged to see OMAF’s apparent renewed interest

in integrated pest management. The ECO hopes that the ministry will continue to build on and actively promote the integrated pest management concept and to discourage (and control, if necessary) the broad-scale prophylactic use of pesticides.

Recommendation 1:

The ECO recommends that the Ministry of Agriculture and Food and the Ministry of the Environment undertake monitoring to determine the prevalence and effects of neonicotinoids in soil, waterways and wild plants.

This is an article from the 2013/14 Annual Report to the Legislature from the Environmental Commissioner of Ontario.

Citing This Article:
Environmental Commissioner of Ontario. 2014. "Plight of the Pollinators." Managing New Challenges, ECO Annual Report, 2013-14. Toronto, ON : Environmental Commissioner of Ontario. 50-58.