‘Conventional pesticides should be the last line of defence’

In April, EU member states voted for a near-total ban on neonicotinoid pesticides, following a review of the evidence linking their use with a reduction in honeybee and wild bee populations. Scientists at the Centre for Ecology & Hydrology published an influential large-scale pan-European field study in June 2017. In this blog post, Professors Richard Pywell and Richard Shore, who lead our Biodiversity and Pollution science areas, respectively, look at the future of crop protection following the ban.

Justification for the ban on neonicotinoids

The new extension to the ban on neonicotinoids to include widely planted crops, such as cereals and sugar beet that are not attractive to bees, reflects concerns about persistence of these compounds in the soil.

There is a risk that some of the neonicotinoid from the seed coatings on wheat and sugar beet will persist in the soil after the crop has been harvested. If a mass-flowering crop, such as oilseed rape, is planted in soils with neonicotinoid residues there is a possibility that the pesticide will be present in the nectar and pollen of the crop, thus potentially exposing bees to the pesticide.

"Now would be a good time to rethink our strategies for crop protection."

These concerns are justified by the recent findings from the CEH Honey Monitoring Scheme that detected widespread neonicotinoid residues in honey associated with oilseed seed rape crops despite the moratorium on their use.

The need for continued monitoring of pesticides

While the European Commission has carried out a review of changes in farmer behaviour in light of the restrictions on neonicotinoid use, it is important that the alternative means of crop protection are carefully monitored to assess their impacts on a wide range of environmental indicators.

This will require continued monitoring of the fate and impacts of pesticide on pollinators and other groups. A good example of this is the recently launched CEH Honey Monitoring Scheme, which works with beekeepers across the UK to collect and analyse honey samples for a range of pesticides.

Honeybee flying in oilseed rape with full pollen basket germany

Future crop protection strategies

Now would be a good time to rethink our strategies for crop protection.

In future, effective and resilient crop protection strategies will need to be truly holistic, requiring the integration of a range of pest and disease control methods.

These might include improved diagnostic and forecasting of pest outbreaks, use of techniques like gene editing to more rapidly produce crop varieties with durable disease resistance, use of traditional control strategies like crop rotation, enhancing underlying natural pest control and the deployment of new biopesticides.

This does not mean no pesticides, rather it means conventional pesticide is the last line of defence rather than the first line, as they are now.

Professor Richard Pywell
Science Area Head, Biodiversity
Centre for Ecology & Hydrology

Professor Richard Shore
Science Area Head, Pollution
Centre for Ecology & Hydrology

 

Additional links:

Staff page of Professor Richard Pywell
Staff page of Professor Richard Shore

Additional information:

  • CEH was funded by Bayer and Syngenta in 2015-2016 to undertake a pan-European experiment on the effects of neonicotinoids on honeybees and wild pollinators. The findings were published in a paper published in June 2017. See our news story.
     
  • A CEH report in 2016 also linked exposure to neonicotinoid-treated oilseed rape crops with long-term population decline of wild bee species across the English countryside. See our news story.
     
  • The CEH Honey Monitoring Scheme detected widespread neonicotinoid residues in honey associated with oilseed rape crops despite the EU moratorium on their use. Its report was published in January 2018. See our news story.

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