New studies on effects of fungicides and herbicides on bees

Published 07 December 2021

Horticulture and potatoes Crops Environment Science and technology
Self

November was a busy month for research and updates about plant protection products and their potential impacts on pollinators. NFU senior regulatory affairs adviser Dr Chris Hartfield gives an overview of the findings and latest news.

We’re used to hearing about new research on the impacts of insecticides on bees, but last month we saw two new studies from researchers at Royal Holloway University of London that looked at the effects of fungicides and herbicides.

Impacts of fungicide co-formulants

In the first study, 'Co-formulant in a commercial fungicide product causes lethal and sub-lethal effects in bumble bees', the researchers looked at the impact of the fungicide product Amistar on bumble bees.

They studied the effects of the product and its separate components, including the active ingredient azoxystrobin and surfactant co-formulants known as alcohol ethoxylates. In short, the study found this co-formulant had damaging effects on bees, but the active ingredient did not.

The opinion of the researchers was this shows the possible effects of plant protection product co-formulants need to be assessed as closely as the active ingredients.

Lab-based study

This was a lab-based study and as with all lab-based studies, our key concern is whether or not the dose used in the lab was representative of what bees might be exposed to in real fields, and whether any effects seen in the lab are then seen in real fields when bees are behaving naturally in and around treated crops.

In this study, individual bumble bees were kept in an unnatural situation, starved, then fed sugar solution laced with the fungicide product or its constituent parts.

When we looked closely at the study, we found the dose given to the bees was unrealistically high, to the extent that a bumble bee in a real field would need to consume nearly two hundred times its own body weight in nectar, in a single feed, to get the same level of exposure.

Providing evidence

The study also referenced another study that it says provided some evidence similar effects do occur at a field realistic level. We found the referenced study doesn’t provide this evidence. However, we’re told other as yet unpublished work by the second study’s authors will argue this.

The unfortunate thing about this study on fungicide co-formulants was the reaction to it – it was immediately picked-up and shouted about by some organisations as clear evidence of pesticide impacts on bee populations out in the real world, when in fact, if they took the time to read the paper, the results didn’t show any clear evidence of this at all.

Impacts of glyphosate

Later in November, the same group of researchers published a study about the impacts of glyphosate on bumble bees, on its own and in combination with another stress factor – a common parasite of bees.

Unlike the first study, there was little reaction on social media or in the press to this work. It might have had something to do with the fact the study concluded that glyphosate, as an active ingredient, is unlikely to be harmful to bumble bees either alone, or alongside the parasite.

Glyphosate has, however, made some headlines in the last week, with Germany’s new coalition government restating the commitment made at the beginning of the year to take glyphosate off the German market by the end of 2023. Such a move would potentially go against EU law if glyphosate was re-approved by the EU next year.

Neonicotinoid emergency authorisations assessed by EFSA

Other news that failed to grab much attention in the media was the outcome of the European Food Safety Authority’s (EFSA) assessment of emergency authorisations granted by 11 EU Member States for the use of neonicotinoids on sugar beet in 2020 and 2021.

There was a total of 17 emergency authorisations for plant protection products containing the neonicotinoids clothianidin, imidacloprid, thiamethoxam and thiacloprid. These were granted by Belgium, Croatia, Denmark, Finland, France, Germany, Lithuania, Poland, Romania, Slovakia and Spain.

Regulatory processes

Last year, the European Commission asked its scientific experts in EFSA to assess whether these emergency authorisations were in line with the regulation and justified because there was a danger to crops ‘which cannot be contained by any other reasonable means’.

EFSA concluded that in all 17 cases the emergency authorisations were justified, either because no alternative controls were available or because of the risk the pest could develop resistance to available alternatives.

The NFU has long agreed with the need for plant protection product regulatory processes and related policies to develop over time as our understanding and knowledge improves.

However, this should be based on science and evidence where the starting point is a realistic understanding of the risk. This in turn should help farmers and growers to ensure that any use of plant protection products is justified.

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