Bees’ exposure to pesticides – careful evaluation needed

Bees’ exposure to pesticides – careful evaluation needed

In the past years, it became clear that bees’ exposure to pesticides is a complex thing. The incidents around neonicotinoids brought to the attention ways of exposure that nobody thought of before. For bees, residues in pollen and nectar were considered the “standard” risk, maybe also the contact during the spraying or with sprayed parts of the plant. But coated seeds? They get into the soil long time before the flowers emerge, so there’s no risk for bees – that was the consensus. Well, history proofed it wrong. The incidents in the Rhine Valley in 2008 and other occurrences brought to attention dust drift and guttation droplets.

In the beginning, I often heard: “We just have to change our approach to risks during sowing.”. Rapidly, there were risk mitigation measures, technical approaches to avoid dust drift. And the advice to offer alternative water sources to avoid that bees take guttation from plants grown from seeds coated with neonicotinoids. We all know that this wasn’t the end of the story. Ten years later, the EU banned all outdoor uses of imidacloprid, clothianidin and thiomethoxam. I already commented on why I think this doesn’t “save the bees“, despite all claims this is the case.

The EU ban and Belgium’s emergency authorisation

After the ban, it was clear that it would take some time to implement the ban. In addition, there is the possibility of emergency authorisations. This week, I stumbled over a post that Belgium applied such an emergency authorisation for beets, lettuce and carrots. These exceptions are valid for 120 days, i.e. three months, and apply only if there are no other reasonable methods to control the pests. Older pesticides, applied before the appearance of neonicotinoids may not be a reasonable alternative due to other issues. Apparently, Belgium considers that this is the case for beets, carrots and lettuce.

Exposure to pesticides is a complex topic as well. From the information given on this decision, I’m sure Belgium evaluated the issue well. And though I agree that there shouldn’t be a risk for HONEY bees by the uses included in the emergency authorisation, there are some considerations that I think are important. First of all, as an advocate of bees, I don’t like this extension from honey bees to “bees”, which are more than 20,000 species worldwide. In Belgium, there is only a small part of this diversity, but, however, many of them nest in the ground. And this way of exposure to pesticides is hardly evaluated. There are also others, listed in a comment under the post. The truth is, we don’t have enough data about “all ways of exposure”, that’s merely impossible.

Bees’ exposure to pesticides – a work in progress

If you’ve read some more articles on this blog, you know that I struggle with simplification. In my opinion, it’s something completely different if you make science and other complex topics available or if you paint them black and white to simplify. I understand that sometimes it’s not easy to avoid, I struggle with it every time I write something. But there are subjects in which simplifying leads to escalation and the situation with neonicotinoids, or, more in general, bees’ exposure to pesticides is such a topic.

It’s important to understand that science is always a work in progress. The available data on exposure, risks etc. are always only snapshotting the situation. This is why the results of studies on the effects and risks of neonicotinoids – and other pesticides – sometimes contradict each other. The agricultural practices in different countries are different. So are their bee or pollinator species or those which live or nest in an agricultural landscape. There are many “what if?”-questions to answer, the topic isn’t as linear as it often seems.

The best way to understand these “what if?”-questions are through monitoring studies. They reflect the given circumstances, the realistic situation during the sowing and the later development of the crop. In the Belgian case, an accompanying monitoring study during the emergency authorisation would surely clarify some of these questions. And, by the way, I would be more than happy to give advice on how to design and perform these studies. Anyway, emergency authorisations need careful evaluation of the circumstances. And careful communication of the reasons and limitations.


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