1. Key points

• Pesticides travel well beyond the treated plots: dwellings, dust, water, pollen, bee bread and wax can all carry traces of them.
• The French PestiLoge and PestRiv studies mainly document exposures; they do not directly demonstrate a health risk or a loss of colonies.
• The debate over acetamiprid shows that a heavily publicised molecule can mask other risks: pyrethroids, fungicides, mixtures and conditions of application.
• The European regulatory projects discussed in the article raise a central question: what level of effect on bees does a society consider “acceptable”?
• Swiss data on bee bread, wax and surface waters confirm that this problem also concerns the apiaries of Switzerland and temperate Europe.

2. What the study shows

The two articles do not summarise a single experimental study, but offer a critical synthesis of recent data on pesticide exposure and on the evolution of the regulatory framework.

Question. The two parts of the article raise a broad question: what do recent data show about involuntary exposure to pesticides, and what are the French and European regulatory debates changing for bees, pollinators and human health?

Method. The first part draws in particular on two recent French surveys. PestiLoge searched for pesticides in the air and in household dust. PestRiv compared the exposure of people living near vineyards with that of people living far from agricultural land. The second part mainly examines the projects to evolve the European framework for pesticide assessment, in particular the “uniform principles” and the regulatory package known as Omnibus X.

Results. PestiLoge shows that dwellings can contain a mixture of substances of various origins: agricultural pesticides, household biocides, veterinary antiparasitics, mosquito repellents and persistent legacy substances. Agricultural proximity is associated, in this study, with higher glyphosate levels in dust. PestRiv shows that residents living near vineyards are more exposed than non-residents, and that this exposure varies with treatment periods, quantities applied and distance to the vines. These results document exposure; they do not directly measure health effects.

The first part then uses the French controversy around the Loi Duplomb to show how a public debate can focus on a single emblematic molecule. The initial bill sought to lift the French ban on neonicotinoids; the text finally adopted maintained the general ban but opened the way to conditional derogations, in particular when no effective alternatives are available. The French Constitutional Council struck down this provision, so that, within the framework described by the article, the use of neonicotinoids and substances with a similar mode of action remains banned in France.

The article highlights acetamiprid not to portray the molecule as harmless, but to place the risk back in its context. The LD50 values cited are telling: etofenprox and deltamethrin, two pyrethroids mentioned in the article, show LD50 values of about 0.038 and 0.0015 micrograms per bee, compared with 8.09 micrograms per bee for acetamiprid. The message is therefore not that acetamiprid is toxicologically uninteresting, but that real exposure, timing of application, flowering, water collected, spray drift and the other molecules must be brought into the analysis. The second part shifts the discussion to the European level. It recalls that the honey bee is assessed as a component of the environment, and not as livestock producing foodstuffs. This distinction is decisive: in the regulatory interpretation discussed by the article, certain harmful effects can be judged acceptable for the environment. The article particularly criticises the threshold of a 10% reduction in the size of a bee colony, regardless of season, initial colony strength and category of individuals affected.

The proposed revisions of the uniform principles plan to better document certain sublethal effects, effects on larvae, behaviour, survival and colony development. But the article also points out possible regressions, for instance the disappearance of the risk assessment for the consumption of contaminated water by bees, even though such exposure pathways can be relevant at the apiary.

The Omnibus X package is presented by the European Commission as an administrative simplification. The article rather sees in it a deregulation risk: potentially unlimited authorisations for certain active substances, less systematic reassessment in the light of new knowledge, easier procedures for so-called biocontrol substances, and possibilities of provisional or tacit authorisations. The “biocontrol” category is judged particularly problematic when it includes not only microorganisms or simple natural substances, but also organisms derived from new genetic techniques, interfering RNAs (RNAi) or chemically modified molecules of natural origin.

The article finally places these developments in a broader political and economic context: the growing weight of European lobbying, industrial concentration in the crop-protection sector, and the tension between the environmental objectives of the Green Deal and the drive for regulatory simplification. According to the article, the four main groups in the crop-protection sector would represent more than half of the world market, which gives considerable weight to their interests in regulatory debates.

Interpretation. The two texts taken together call for a more realistic reading of pesticide risk: reasoning molecule by molecule is not enough, nor is sticking to laboratory acute toxicity tests. Real exposures are multiple, seasonal, tied to landscapes, to agricultural practices, to domestic uses and to the matrices in which substances accumulate — such as wax, pollen or bee bread.

3. Critical assessment

The strength of this synthesis lies in linking human health, regulation and bees; its main limitation is that it mobilises a great deal of exposure data, but fewer direct lines of evidence for effects at colony level.

The main strength of these two articles is to move beyond the simplistic opposition between “authorised molecule” and “banned molecule”. They show that the real issue lies in exposure: drift, dust, indoor air, water, residues in pollen, recycled wax, mixtures of substances and timing of application. For beekeeping, this approach is more useful than a reading centred on a single product.

Another strength is the reminder that bees are not exposed only in large, attractive crops. They can come into contact with residues via weeds, field margins, water collected, dust, wax, or crops that are not always considered major resources. This point is particularly important for apiaries placed in mosaic agricultural landscapes.

The first limitation is that the two French studies highlighted in the article document mainly exposures. PestRiv does not draw conclusions about the health risk to residents; PestiLoge likewise does not allow a clinical effect to be attributed to a given substance. For bees, the mere presence of residues in the environment or in a hive matrix is not, on its own, enough to demonstrate poisoning or a weakening of the colony.

The second limitation concerns transferability. The debates around the Loi Duplomb belong to the French context. The European framework influences Switzerland but does not automatically apply there in the same way. In Switzerland, authorisations, restrictions of use and conditions of application must be checked in the official register of plant-protection products at the time of publication or practical use. The status of a substance can change rapidly.

The third limitation is that of mixtures. The articles rightly stress that colonies encounter cocktails of substances. But the toxicological evaluation of mixtures remains difficult: effects may be additive, synergistic, antagonistic or simply unknown. The fact that a mixture is detected does not yet say at what dose it acts, nor on which bee stage, nor with what effect on the colony as a whole.

Finally, the Alsatian case mentioned in the first part is interesting, but it remains essentially a professional testimony. It can feed the reflection on the evolution of viticultural practices, but should not be presented as scientific evidence of a generalised drop in bee mortality near vineyards.

4. What related studies show

Related studies mainly confirm the reality of multiple exposures. The Swiss data are particularly useful for linking the French and European debate to the apiaries of our regions.

Swiss data on bee bread. Schaad et al. analysed bee bread sampled from five colonies of a Swiss apiary located in an agricultural area. Thirty pesticides were identified, twenty-six of them quantified. Among the substances found were acetamiprid, thiacloprid, several fungicides — including boscalid, cyprodinil, difenoconazole and trifloxystrobin — as well as herbicides such as prosulfocarb and terbuthylazine. This study does not prove direct damage to colonies, but it confirms that bees can bring back to the hive a mixture of agricultural substances over the course of the season.

Pollen can also feed the contamination of wax. Kast, Müller and Fracheboud followed the temporal entry of pesticides through pollen and their fate in wax, also in a Swiss agricultural environment. Their study shows that several substances present in pollen are subsequently quantifiable in wax. Lipophilic compounds may persist through purification and recycling. For the beekeeper, this result is important: wax is not a simple neutral substrate, but can become an accumulation compartment.

Bee bread complements water monitoring. Stalder et al. propose using bee bread as a terrestrial biomarker of pesticide exposure. In two Swiss apiaries, they detect part of the substances sought in bee bread, with profiles that do not always match those observed in water. Some molecules are better captured by bees than by classical water-monitoring programmes, particularly when their environmental behaviour limits their presence in water samples.

Swiss commercial wax also contains residues. Marti, Kilchenmann and Kast analysed Swiss commercial foundation. Several residues were found, in particular former apicultural acaricides such as coumaphos and tau-fluvalinate, but also other substances such as DEET or piperonyl butoxide. This is a reminder that colony exposure does not come only from the agricultural landscape: it can also pass through the beekeeping equipment, past treatments and the wax-recycling cycle.

Fungicides are not always well captured by classical tests. Fisher et al. tested in field colonies a widely used fungicide, Pristine®, combining boscalid and pyraclostrobin. The study reports a dose-dependent reduction in the lifespan of workers and in colony population size, with effects observed at concentrations relevant to certain agricultural situations. This study should not be transposed mechanically to Swiss vineyards, since the context concerns specific agricultural conditions. It nonetheless supports the idea that laboratory tests based mainly on acute toxicity can underestimate certain effects at colony level.

Fungicide–insecticide mixtures remain a sensitive zone. The review by Schuhmann et al. shows that certain fungicides can increase the toxicity of neonicotinoids or pyrethroids for bees, particularly when the molecules interfere with detoxification systems. This literature does not warrant the conclusion that every fungicide is dangerous in every situation, but it justifies no longer treating them as automatically harmless to pollinators.

Acetamiprid illustrates the limits of LD50 alone. Recent work shows sublethal effects of acetamiprid on neurological, physiological or behavioural parameters in the honey bee. Mackei et al. report disturbances of the brain redox balance after sublethal exposure; Shi et al. describe effects on lifespan and foraging behaviour. These results must be interpreted with caution for the apiary: on their own, they do not demonstrate colony collapse under Swiss conditions. They mainly show that acute toxicity does not capture the full extent of risk.

Bumble bees confirm the importance of a broader assessment. Nicholson et al. monitored 316 colonies of Bombus terrestris at 106 agricultural sites in eight European countries. The pesticides found in the pollen collected by bumble bees were associated with reduced colony performance, especially in simplified and intensive landscapes. This study does not concern the honey bee, but it reinforces the idea that risk assessment must also consider non-Apis pollinators, landscapes and post-authorisation monitoring.

Alpine viticultural and fruit-growing landscapes give converging signals. In South Tyrol, Cech et al. studied contamination of non-agricultural areas close to orchards and vineyards. Drift-mitigation measures appear to have reduced certain contamination levels, without eliminating potential risks for the environment and human health. This context is not Swiss, but it is geographically and agronomically close to certain Alpine regions with perennial crops.

Swiss waters tell a comparable story. Moschet et al. showed that a broad pesticide screening in Swiss rivers detects far more substances than monitoring schemes limited to a few molecules. Spycher et al. more recently emphasise that European strategies for pesticide monitoring in waters remain heterogeneous, while Switzerland has developed a more formalised link between chemical monitoring and regulation. This does not replace apiary monitoring, but confirms the importance of a broad environmental approach.

5. What does this mean at the apiary?

For an apiary in Switzerland or in temperate Europe, the practical message is to observe, document, renew the wax and engage in dialogue with neighbouring growers — without jumping to conclusions from a single residue.

• An apiary near vineyards, orchards, vegetable crops or arable crops deserves particular attention during treatment periods. This does not mean that such locations should be avoided systematically, but that pesticide risk should be integrated into the choice of site, the observation of colonies and the dialogue with growers.
• The presence of residues in pollen, bee bread or wax must be interpreted with caution. It signals an exposure, not necessarily a poisoning. In case of unusual mortality, residues should be cross-checked with other signs: acute mortality in front of the hives, abnormal behaviour, timing of treatments, weather, neighbouring crop and health status of the colonies.
• Wax management remains a concrete lever. The Swiss studies confirm that certain substances can accumulate in wax and survive recycling. Regular comb renewal, setting aside doubtful wax, and caution with very old or heavily contaminated wax appear consistent with these results.
• Fungicides should not be ignored. Even though they are not designed to kill insects, some can contribute to sublethal effects or to interactions with insecticides. This caution is particularly important near intensively treated perennial crops.
• For heavily debated substances, such as acetamiprid, the Swiss beekeeper must check the current situation in the official registers before drawing conclusions. 
• In case of suspected poisoning, the situation must be documented quickly: date, location, photographs, weather, neighbouring crops, products possibly observed, symptoms and evolution of the colonies. The practical link runs directly to the Swiss bee-poisoning protocol sheet, which helps record observations and samples.

Read the original articles

Kievits J., 2026, “Pesticides, abeilles et santé humaine : des cadres réglementaires en mutation. Partie I, la situation nationale”, La Santé de l’Abeille, no. 331, January–February 2026, pp. 63–74.

Kievits J., 2026, “Pesticides, abeilles et santé humaine : des cadres réglementaires en mutation. Partie II, la situation européenne”, La Santé de l’Abeille, no. 333, May–June 2026, pp. 52–65.

 

Further reading on ApiSavoir

• Practical Guide: 3.1.1 Bee Poisoning Protocol Sheet
• Practical Guide: 3.1.2 Bee Poisoning
• Sentinel bees: what hives and wild bees reveal about the environment
• Neonicotinoids
• Wax hygiene: a central lever of colony health
• When combs grow old: impacts on bees and honey quality

 

Bibliography

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Fisher A., DeGrandi-Hoffman G., Smith B., Johnson M., Kaftanoğlu O., Cogley T., Fewell J. & Harrison J., 2020, “Colony field test reveals dramatically higher toxicity of a widely-used mito-toxic fungicide on honey bees (Apis mellifera)”, Environmental Pollution, 115964.

Kast C., Müller J. & Fracheboud M., 2024, “Temporal entry of pesticides through pollen into the bee hive and their fate in beeswax”, Environmental Science and Pollution Research International, 31, pp. 61060–61072.

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