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Bee Safety of Imidacloprid Seed Treatment to Sunflower J. Keppler, Ch. Maus, R. Schmuck, A. Nikolakis, T. Schneider.

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Presentation on theme: "Bee Safety of Imidacloprid Seed Treatment to Sunflower J. Keppler, Ch. Maus, R. Schmuck, A. Nikolakis, T. Schneider."— Presentation transcript:

1 Bee Safety of Imidacloprid Seed Treatment to Sunflower J. Keppler, Ch. Maus, R. Schmuck, A. Nikolakis, T. Schneider

2 Imidacloprid Seed-Dressing Sunflower: Bee Safety Exposure of honey bees to Imidacloprid (seed treatment)  Plant metabolism  Residues in bee-relevant matrices

3 Imidacloprid Seed-Dressing Sunflower: Bee Safety Uptake and translocation rate The overall uptake of seed dressed imidacloprid (incl. other soil applications) into plants is between 1.6 and 4.9 % The metabolism studies resulted as follows:

4 Imidacloprid Seed-Dressing Sunflower: Bee Safety Systemicity Principle As the mobility of imidacloprid in the xylem is high, the acropetal translocation to shoots and leaves is good (systemicity). The highest imidacloprid concentrations in plants are found in the oldest leaves. The translocation of imidacloprid and its metabolites via the phloem (basipetal translocation) to e. g. storage organs, roots, and fruits is low.

5 Imidacloprid Seed-Dressing Sunflower: Bee Safety Discussion of bee-relevant metabolites Bee relevant metabolites were not detected in bee-relevant matrices (pollen and/or nectar) after seed-dressing applications of relevant crop cultures. Nevertheless, the bee relevant metabolites were included in the analytical method for residue studies precautionary.

6 Imidacloprid Seed-Dressing Sunflower: Bee Safety LOQ Imidacloprid: 5 ppb LOD Imidacloprid: 1.5 ppb n.d.: not detectable; < LOD Conclusion: residues in bee-relevant matrices of sunflowers never found Maximum residue levels of imidacloprid detected in respective plant matrices in the field Residue levels in bee-relevant plant matrices Sunflower Nectar > 4 studies Sunflower Pollen > 4studies Imidaclopridn.d.

7 Imidacloprid Seed-Dressing Sunflower: Bee Safety Hydroxy-Imidacloprid: LOQ 5 ppb; LOD 1.5 ppb Olefine-Imidacloprid: LOQ 10 ppb; LOD 3.0 ppb n.d.: not detectable;< LOD Conclusion: bee-relevant metabolites not detectable Residue levels in nectar and pollen Field residue levels of bee-relevant imidacloprid metabolites Sunflower NectarSunflower Pollen Hydroxy –Imidaclopridn.d. Olefine-Imidacloprid n.d.

8 Imidacloprid Seed-Dressing Sunflower: Bee Safety Succeeding crops – soil residues  Imidacloprid should protect seeds and plants during the growth phase, rendering the repeated use of plant protectants superfluous.  A certain degree of stability (persistence) for the a. i. in the soil is therefore necessary.  Residual amounts of imidacloprid in soil become more and more firmly attached to the soil matrix through natural binding processes.  Aged soil residues of imidacloprid are therefore less biologically available and do not pose a risk to the environment.  Numerous studies by independent experts and BCS reveal that imidacloprid is continuously degraded by microbes and is ineffective in the following agricultural cultivation period. Bayer CropScience AG (2002): Environmental fate of imidacloprid, Pflanzenschutznachrichten Bayer, Vol. 55, Special edition)

9 Imidacloprid Seed-Dressing Sunflower: Bee Safety Accumulation Trials over several years – long term dissipation studies with repetitive applications – confirmed that imidacloprid does not accumulate in soil. Bayer CropScience AG (2002): Environmental fate of imidacloprid, Pflanzenschutznachrichten Bayer, Vol. 55, Special edition)

10 Imidacloprid Seed-Dressing Sunflower: Bee Safety Effects of Imidacloprid (seed treatment) on honey-bees  Acute effects (laboratory)  Chronic effects (laboratory)  Tunnel & field studies

11 Imidacloprid Seed-Dressing Sunflower: Bee Safety Intrinsic acute bee toxicity Imidacloprid  Regulatory LD 50 (oral): 3.7 ng/bee  NOEC: 42 ppb  LD 50 (contact): 42.9 ng/bee or greater

12 Imidacloprid Seed-Dressing Sunflower: Bee Safety Acute sublethal effects  Lowest NOEC in reliable olfactory conditioning test: 50 ppb.  No or less pronounced effects for metabolites. BCS conclusion:  No acute sublethal effects e. g. on learning behaviour of bees at acute dietary NOEC of 42 ppb.

13 Imidacloprid Seed-Dressing Sunflower: Bee Safety Chronic lethal effects  Reliable laboratory studies showed no increased mortality after chronic exposure to dietary concentrations of 10 ppb or lower. However, no increased mortality was found for > 20 ppb under more realistic exposure conditions (tunnel or field studies).

14 Imidacloprid Seed-Dressing Sunflower: Bee Safety Chronic sublethal effects  No chronic mortality and no anti-feedant effects < 20 ppb  Hive development not adversely affected at concentrations < 20 ppb  No loss of foraging bees at < 100 ppb BCS conclusion:  NOAEC under field conditions > 20 ppb

15 Imidacloprid Seed-Dressing Sunflower: Bee Safety Effect threshold under field conditions Under field conditions no adverse effects (NOAEC) at 20 ppb  No acute or chronic mortality  No adverse effects on colony strength and brood development  No losses of foraging bees due to impacts on orientation

16 Imidacloprid Seed-Dressing Sunflower: Bee Safety Field-relevant NOAEC value 20 ppb is considered a field-relevant NOAEC since  No chronic mortality occurred at < 20 ppb  No anti-feedant responses occurred at < 20 ppb  Hive performance was not impaired at < 20 ppb  No loss of foraging bees was observed at < 100 ppb

17 Imidacloprid Seed-Dressing Sunflower: Bee Safety Conclusion on higher tier studies  The field relevant NOAEC is > 20 ppb.

18 Imidacloprid Seed-Dressing Sunflower: Bee Safety Imidacloprid residue level detected in the field in relevant matrices of sunflower: < LOD (= 1.5 ppb) NOAEC under field conditions: > 20 ppb  Negligible Risk to Honeybees Risk assessment Comparison of maximum exposure and NOAEC * 1 ppb = 1 part per billion = 1 µg / kg = %

19 Imidacloprid Seed-Dressing Sunflower: Bee Safety BCS-France Sunflower BBA, Germany Rape AgView, Canada Rape Hohenheim- Germany,Phacelia BCS-France Sunflower BCS-Germany Mais BCS-Germany Sunflower BCS-Germany Summer rape BCS-GB/Sweden Sunflower BCS-GB/Sweden Summer rape 3x ACTA, France Sunflower 3x2x Cultures - Sunflower - Summer rape - Winter rape - Phacelia - Maize Various - Countries - Climates - Soils - Bee colonies - Colony sizes No effect on bees in 18 tunnel studies 18 International tunnel studies Bayer CropScience studies external studies

20 Imidacloprid Seed-Dressing Sunflower: Bee Safety / CONICET, ARG Sunflower Celle, Ger Rape Uni Guelph, CAN Rape Uni Minnes., USA Rape Mayen, Ger Sunflower Facanc., Hung Sunflower ACTA, France Sunflower CNEVA, France Sunflower Mayen, Ger Sunflower BCS-Germany Sunflower BCS-France Sunflower 1998/ BCS-France Sunflower ACTA, France Sunflower 14 International field studies Bayer CropScience studies external studies Cultures - Sunflower - Summer rape - Winter rape - Phacelia - Maize Various - Countries - Climates - Soils - Bee colonies - Colony sizes No effect on bees in 14 field studies

21 Imidacloprid Seed-Dressing Sunflower: Bee Safety Thank you very much for your kind attention!


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