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Research about controversial neonicotinoid insecticides

3 March, 2018
Global scientific review reveals effective alternatives to neonicotinoid and fipronil insecticides. eurekalert.org. February 26, 2018. Report finds systemic pesticides not as effective as once thought and cites pest resistance as key reason to end mass uses of the harmful substances. Use of controversial neonicotinoid insecticides ("neonics") in agriculture is not as effective as once thought, and can be replaced by advantageous pest-management alternatives, according to a study1 published today in the Springer journal Environmental Science and Pollution Research.
Research about controversial neonicotinoid insecticides
This latest publication of the Task Force on Systemic Pesticides reviews 200 studies to assess mass use of systemic insecticides in agriculture, focusing on their effects on crop yields and the development of pest resistance to these compounds after two decades. While neonics were first brought into use in 1991, documented resistance to them dates as far back as 1996. The authors identify a diverse range of alternative pest-management strategies available for large-scale crop production, concluding that a new framework is needed for a truly sustainable agricultural model that relies mainly on natural ecosystem services instead of highly toxic chemicals.
"Over-reliance on systemic insecticides for pest control is inflicting serious damage to the environmental services that underpin agricultural productivity," said Task Force co-chair and scientist at France’s National Scientific Research Centre Jean-Marc Bonmatin. "This new research is exciting because it’s proven the existence and feasibility of a number of alternative, integrated pest management models — which are far better for the environment without increasing costs or risks for farmers."
Neonicotinoids and the phenylpyrazole fipronil are the world’s most sold systemic insecticides. They are routinely used in agriculture as seed treatments even where there is no relevant pest threat. After two decades of extensive neonics use, studies2 show these pesticides can have disastrous effects on biodiversity and ecosystems, including harm to pollinators.
"Insecticides are expected to achieve higher yields and net incomes, but this certainly is not always the case," Bonmatin said. "The overwhelming evidence of negative effects on pollinators and arthropods needs to be weighed against the pest control benefits these systemic insecticides are supposed to produce."
Today’s report cites many alternative integrated pest-management approaches that can be implemented in combination: at the landscape level (e.g., ecological corridors), by using better farming methods (e.g., crop rotation, resistant crop varieties), by taking advantage of biocontrol (e.g., predators and parasitoids) and through other means (e.g., traps, naturally derived insecticides).
The study also details results of an innovative insurance system that protects farmers against undue financial risks without causing environmental harm. Through a "mutual fund" insurance model piloted in Italy, a collective of farmers manages a mutual fund stock, creating compensation through an interregional distribution of risks. Compensation is commensurate with the financial resources of the fund, which covers risks that private insurance companies currently do not, including climatic adversities such as flooding and damage by wild animals and pests.
"Crop insurance programs can be tailored to reduce the financial risk to farmers from potential pest infestations without the environmental costs of insecticide use," Bonmatin said. "And on a cost-recovery basis, insurance premiums are far cheaper than insecticides, so farmers’ net incomes rise, too. It’s a win-win approach for farmers and the environment."
The European Union is expected to vote soon on a proposal to expand its 2013 moratorium to cover most uses of neonics. France will phase-out all neonics next September. Canada is proposing to phase-out all agricultural uses of the neonic imidacloprid, with a final decision expected in December.
Separately, Canada has also proposed to cancel some uses of other neonics (clothianadin and thiamethoxam), but would continue to permit their main use as seed treatments.
"Regulators need to realize that if we want sustainable agricultural practices, we need a more restrictive regulatory framework and programs to support farmers making the switch," Bonmatin said. "Our findings on the availability of alternatives will be particularly relevant where new restrictions on neonics are being considered."

References:
1. Furlan, L. et al (2018) An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 3: alternatives to systemic insecticides, Environmental Science and Pollution Research DOI: 10.1007/s11356-017-1052-5
2. Pisa, L. et al (2017) An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 2: impacts on organisms and ecosystems, Environmental Science and Pollution Research DOI: 10.1007/s11356-017-0341-3
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Environmental Risks and Challenges Associated with Neonicotinoid InsecticidesMichelle L. Hladik, Anson R. Main, and Dave GoulsonEnvironmental Science & Technology Article ASAPDOI: 10.1021/acs.est.7b06388
Abstract Image
AbstractNeonicotinoid use has increased rapidly in recent years, with a global shift toward insecticide applications as seed coatings rather than aerial spraying. While the use of seed coatings can lessen the amount of overspray and drift, the near universal and prophylactic use of neonicotinoid seed coatings on major agricultural crops has led to widespread detections in the environment (pollen, soil, water, honey). Pollinators and aquatic insects appear to be especially susceptible to the effects of neonicotinoids with current research suggesting that chronic sublethal effects are more prevalent than acute toxicity. Meanwhile, evidence of clear and consistent yield benefits from the use of neonicotinoids remains elusive for most crops. Future decisions on neonicotinoid use will benefit from weighing crop yield benefits versus environmental impacts to nontarget organisms and considering whether there are more environmentally benign alternatives.

Full text
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Neonicotinoids: risks to bees confirmed. efsa.europa.eu.  February 28, 2018. Most uses of neonicotinoid pesticides represent a risk to wild bees and honeybees, according to assessments published today by EFSA. The Authority has updated its risk assessments of three neonicotinoids – clothianidin, imidacloprid and thiamethoxam – that are currently subject to restrictions in the EU because of the threat they pose to bees.These new conclusions update those published in 2013, after which the European Commission imposed controls on use of the substances.
For the new assessments, which this time cover wild bees – bumblebees and solitary bees – as well as honeybees, EFSA’s Pesticides Unit carried out an extensive data collection exercise, including a systematic literature review, to gather all the scientific evidence published since the previous evaluations.
The team also applied the guidance document developed by EFSA specifically for the risk assessment of pesticides and bees.
Jose Tarazona, Head of EFSA’s Pesticides Unit, said: “The availability of such a substantial amount of data as well as the guidance has enabled us to produce very detailed conclusions.
“There is variability in the conclusions, due to factors such as the bee species, the intended use of the pesticide and the route of exposure. Some low risks have been identified, but overall the risk to the three types of bees we have assessed is confirmed.”
EFSA finalised its conclusions following two separate consultations with pesticide experts in the EU Member States. The experts have supported the conclusions.
As with the previous assessments, exposure of bees to the substances was assessed via three routes: residues in bee pollen and nectar; dust drift during the sowing/application of the treated seeds; and water consumption.
Next steps
EFSA’s conclusions will be shared with risk managers from the European Commission and Member States, who will consider potential amendments to the current restrictions on the use of these pesticides.

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