In this post, PhD student, Elena Zioga reflects on the decision by the French government to allow neonicotinoid use, in the same week as she published her first paper on pesticide residues in nectar and pollen…
I decided to take few weeks off work, but my research cannot let me go as things are happening. My review paper on pesticide residues in plant pollen and nectar is now published online and I am very happy to share it with the rest of the world (read more here).
However, my joy is highly contained by the sad news that came out on Thursday, 6 August, when the French Agricultural Ministry announced their decision on lifting the ban on neonicotinoid insecticides used as seed treatment for the sugar beet cultivation.
The neonicotinoid compounds clothianidin, imidacloprid and thiamethoxam were being used in the EU as sugar beet seed coatings in order to control the aphid (Myzus persicae) population on the crop and prevent the Beet Yellows Virus transmission (1). According to the estimates by professionals, taken up by the ministerial press release, this disease can cause yield reductions of up to 30% to 50% (2). Thus, the French government acceded to the requests of the sugar beet growers who believe that there is no other viable alternative to neonicotinoids against the aphids. Hence, in addition to the promise of compensation and the launch of a research effort of 5 million euros, the French government announced a “legislative amendment” allowing “for the 2021 campaign and if necessary the two following campaigns at most” exemptions allowing the use of seeds coated with neonicotinoid insecticides, assuring that these exemptions will only concern sugar beet (2).
In France, the 2016 biodiversity law banned the neonicotinoid insecticides as of September 2018 (3). On December 2018, the EU banned the use of these compounds on flowering and outdoors growing crops (4). “These bans are essential to fight against the massive decline of bee colonies and wild pollinators“, said the Ministry of Agriculture and Food, in an August 2018 statement (5). Back then, that decision was supported by voluminous data on the negative impacts of these compounds on pollinators. What has changed two years later? How is it possible to neglect all the past research and go back to zero? How is it possible, from being a leader in the fight against the pollinator killing neonicotinoids in Europe, that France has apparently become a stooge for the agrochemical and industrial agriculture lobbies? In my opinion, this is an unacceptable setback showing that governments, in an effort to keep their voters happy, might sometimes take decisions that are detrimental for the environment.
I am simply wondering why that same French government who decided to ban the neonicotinoid use two years ago is taking the exact opposite decision now, and with a potential three year plan of application! In their defense, they argued that since sugar beet is harvested before flowering in the field, it would not attract pollinators and the use of neonicotinoids in seed coating on this crop would therefore have no adverse consequence on the bees. It was also argued that usually the sugar beet crop is followed by straw cereals, which are not attractive to pollinating insects. In addition, there were reassurances that there will not be any flowering crops planted the following seasons. Are these sufficient arguments to support this setback?
From my point of view, NO, and here is why:
The exposure of bees and other pollinators to neonicotinoids is mainly through wild flowers. A 2015 study clearly showed that the pollen of wild plants growing in the margins of the seed treated crops was highly contaminated with neonicotinoids, and the honey bees were bringing this pollen back to their hives (6). Moreover, neonicotinoid compounds and their metabolites can be very persistent in the soil (with typical half-lives estimated to be of the order 15-300 days) exhibiting a potential for accumulation in soil following repeated applications (7). Neonicotinoids can be found long after their use has ceased both in the cultivated soils and in plants growing there in subsequent years, thus exposing pollinators to a significant risk (8). A 2020 study evaluating the consequences of the 2013 EU moratorium restricting the use of three neonicotinoid insecticides (clothianidin, imidacloprid and thiamethoxam) by monitoring winter oilseed rape crops for five years following the European moratorium (from 2014 to 2018), concluded: “the three neonicotinoids concerned could be detected in the samples taken. In particular, imidacloprid was detected each year, in total in 43% of the samples analyzed, without a decreasing trend over the years but with a strong inter-annual variation” (9).
Substances applied in soils and as seed treatments may be considered low risk for honey bees (Apis mellifera), which do not collect soil material. However, for other wild bee species (e.g. bumble bees and solitary bees) this may be a rather important route of exposure (10). The majority of wild bee species spend a significant time of their life span in the soil as they may built their nest underground, or even use soil material in order to construct their nests (11, 12). A 2019 study, found that “chronic exposure to nesting substrates contaminated with neonicotinoids may represent an important route of exposure that could have considerable physiological and ecological consequences for bees and plant-pollinator interactions” (13), while a study of 2020 claimed that “native bee richness in non-target field margins may be negatively affected by the use of neonicotinoid seed treatments in agroecosystems” (14).
These data clearly show that a possible exemption for the use of neonicotinoids on sugar beet seeds would have serious consequences for the pollinator communities on and around the seed treated fields, by contaminating the environment around these fields with neonicotinoids and thus posing a hazard to pollinators. Going back to planting neonicotinoid-treated sugar beet seeds should not be considered as a temporary solution for limiting the spread of the Beet Yellows Virus, but as contributing to permanent and constant ecological destruction. There were several reasons that triggered the neonicotinoid ban two years ago, the same reasons that are still in effect nowadays. The only change is the addition of more scientific evidence supporting the damaging effects of neonicotinoids to pollinators.
I consider that the French government must therefore not grant an exemption for the use of neonicotinoids and should instead invest more in research towards finding another solution to preventing the spread of the Beet Yellows Virus. This is the only way to keep both the high yields in sugar production and the pollinators safe!
(1) Neonicotinoids in sugar beet cultivation in Central and Northern Europe: Efficacy and environmental impact of neonicotinoid seed treatments and alternative measures. Hauer et al. J. Crop Prot. 2018, 93, 132-142. https://doi.org/10.1016/j.cropro.2016.11.034.
(6) Neonicotinoid Residues in Wildflowers, a Potential Route of Chronic Exposure for Bees. Botías et al. Environ. Sci. Technol. 2015, 49, 21, 12731-12740. https://pubs.acs.org/doi/abs/10.1021/acs.est.5b03459.
(7) Quantification of Imidacloprid Uptake in Maize Crops. Bonmatin et al. J. Agric. Food Chem. 2005, 53, 5336-5341. https://pubs.acs.org/doi/10.1021/jf0479362.
(8) Neonicotinoids, bee disorders and the sustainability of pollinator Services. Van der Sluijs et al. Curr. Opin. Env. Sust. 2013, 5, 293-305. https://doi.org/10.1016/j.cosust.2013.05.007.
(9) Neonicotinoid-induced mortality risk for bees foraging on oilseed rape nectar persists despite EU moratorium. Wintermantel et al. Sci. Total Environ. 2020, 704, 135400. https://doi.org/10.1016/j.scitotenv.2019.135400.
(10) Pesticide Exposure Assessment Paradigm for Stingless Bees. Cham et al. Environ. Entomol. 2019, 48, 36-48. https://doi.org/10.1093/ee/nvy137.
(11) Workshop on Pesticide Exposure Assessment Paradigm for Non-Apis Bees: Foundation and Summaries. Boyle et al. Environ. Entomol. 2019, 48, 4-11. https://doi.org/10.1093/ee/nvy103.
(12) Pesticide Exposure Assessment Paradigm for Solitary Bees. Sgolastra et al. Environ. Entomol. 2019, 48, 22-35. https://doi.org/10.1093/ee/nvy105.
(13) Chronic contact with realistic soil concentrations of imidacloprid affects the mass, immature development speed, and adult longevity of solitary bees. Anderson and Harmon-Threatt. Sci. Rep. 2019, 9, 3724. https://doi.org/10.1038/s41598-019-40031-9.
(14) Reduced species richness of native bees in field margins associated with neonicotinoid concentrations in non-target soils. Main et al. Agric. Ecosyst. Environ. 2020, 287, 106693. https://doi.org/10.1016/j.agee.2019.106693.