1. Exposure of honey bees to Imidacloprid (seed treatment) Plant metabolism

1. Bee Safety of ImidaclopridSeed Treatmentto SunflowerJ. Keppler, Ch. Maus, R. Schmuck, A. Nikolakis, T. Schneider

2. 1. Exposure of honey bees to Imidacloprid (seed treatment) • Plant metabolism • Residues in bee-relevant matrices

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

4. 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. 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. Residue levels in bee-relevant plant matrices Maximum residue levels of imidacloprid detected in respective plant matrices in the field LOQ Imidacloprid: 5 ppb LOD Imidacloprid: 1.5 ppb n.d.: not detectable; < LOD Conclusion: residues in bee-relevant matrices of sunflowers never found

7. Residue levels in nectar and pollen Field residue levels of bee-relevant imidacloprid metabolites 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

8. 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. 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. 2. Effects of Imidacloprid (seed treatment) on honey-bees • Acute effects (laboratory) • Chronic effects (laboratory) • Tunnel & field studies

11. Intrinsic acute bee toxicity Imidacloprid • Regulatory LD50 (oral): 3.7 ng/bee • NOEC: 42 ppb • LD50 (contact): 42.9 ng/bee or greater

12. 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. 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. 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. 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. 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. Conclusion on higher tier studies • The field relevant NOAEC is >20 ppb.

18. * 1 ppb = 1 part per billion = 1 µg / kg = 0.000 000 1 % Risk assessment Comparison of maximum exposure and NOAEC 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

19. 18 International tunnel studies Bayer CropScience studies external studies 2001 1995 1998 1996 1999 1997 2000 Various - Countries - Climates - Soils - Bee colonies - Colony sizes 3x 2x BCS-Germany Summer rape BCS-GB/SwedenSummer rape 3x 3x Cultures - Sunflower - Summer rape - Winter rape - Phacelia - Maize BCS-GB/SwedenSunflower BCS-GermanySunflower Hohenheim- Germany,Phacelia AgView, CanadaRape BCS-FranceSunflower BCS-FranceSunflower ACTA, FranceSunflower BBA, GermanyRape BCS-GermanyMais No effect on bees in 18 tunnel studies

20. Bayer CropScience studies external studies CNEVA, FranceSunflower Facanc., HungSunflower Uni Minnes., USARape ACTA, FranceSunflower ACTA, FranceSunflower BCS-GermanySunflower Celle, GerRape Uni Guelph, CANRape BCS-FranceSunflower BCS-FranceSunflower ACTA, FranceSunflower Mayen, GerSunflower Mayen, GerSunflower CONICET, ARGSunflower 2000 1995 1999 1998/2 1998/1 1996 1997 14 International field studies Various - Countries - Climates - Soils - Bee colonies - Colony sizes Cultures - Sunflower - Summer rape - Winter rape - Phacelia - Maize No effect on bees in 14 field studies

21. Thank you very much for your kind attention!