I'm no expert on this topic but these studies below seem convincing even if they were done by the chemical industry. Perhaps the experiments are flawed ....anyone care to comment? OR does anyone have data that shows opposite conclusions? From what I can determine corn and cotton in the US are the most likely large plots of Imidacloprid treated crops in the USA. While the material has other labeled uses corn and cotton appear to be the big tonnage. Thus I don't find the hand wringing and speculation swirling around Imidacloprid very convincing especially when the corn & cotton belt in the USA has been quite absent from any large unexplained bee losses aka CCD. This paper is from Bayer Uptake, translocation and metabolism of imidacloprid in plants http://www.bulletinofinsectology.org/pdfarticles/vol56-2003-035-040sur.pdf Conslusions More than 15 studies with imidacloprid have been car- ried out concerning uptake, translocation and metabo- lism in various plant species mainly after foliar, soil or seed treatment. The uptake after soil or seed treatment is about 5% of the applied dose and the a.s. shows good acropetal mobility within the xylem and poor basipetal translocation within the phloem. Three principal meta- bolic pathways of imidacloprid in plants were identified showing a quick degradation of the a.s., especially after seed or soil application. The findings of the metabolism studies show a clear and consistent picture. It can be concluded that in nearly all crops the metabolic pathway of imidacloprid runs via the same three routes and re- sults in qualitative and quantitative similar composition of the metabolic spectrum. All identified metabolites still contain the 6-chloropicolyl moiety of imidacloprid. Hence, the relevant residue to be analysed in field resi- due trials can be defined as the sum of imidacloprid and its metabolites containing the 6-chloropicolyl moiety, expressed as imidacloprid. The nature of the residue in bee-relevant matrices of oilseeds (sunflower nectar and pollen) was determined to consist of the parent compound imidacloprid only. Field residue trials with imidacloprid after seed-dressing of sunflower, corn and rape revealed that no residues above the limit of quantitation of the residue analytical method were present in pollen and nectar. an older study from Bayer with similar results http://www3.interscience.wiley.com/cgi-bin/abstract/77005622/ABSTRACT Abstract In a greenhouse metabolism study, sunflowers were seed-treated with radiolabelled imidacloprid in a 700 g kg-1 WS formulation (Gaucho® WS 70) at 0.7 mg AI per seed, and the nature of the resulting residues in nectar and pollen was determined. Only the parent compound and no metabolites were detected in nectar and pollen of these seed-treated sunflower plants (limit of detection <0.001 mg kg-1). In standard LD50 laboratory tests, imidacloprid showed high oral toxicity to honeybees (Apis mellifera), with LD50 values between 3.7 and 40.9 ng per bee, corresponding to a lethal food concentration between 0.14 and 1.57 mg kg-1. The residue level of imidacloprid in nectar and pollen of seed-treated sunflower plants in the field was negligible. Under field-growing conditions no residues were detected (limit of detection: 0.0015 mg kg-1) in either nectar or pollen. There were also no detectable residues in nectar and pollen of sunflowers planted as a succeeding crop in soils which previously had been cropped with imidacloprid seed- treated plants. Chronic feeding experiments with sunflower honey fortified with 0.002, 0.005, 0.010 and 0.020 mg kg-1 imidacloprid were conducted to assess potential long-term adverse effects on honeybee colonies. Testing end-points in this 39-day feeding study were mortality, feeding activity, wax/comb production, breeding performance and colony vitality. Even at the highest test concentration, imidacloprid showed no adverse effects on the development of the exposed bee colonies. This no-adverse-effect concentration of 0.020 mg kg-1 compares with a field residue level of less than 0.0015 mg kg-1 ( = limit of detection in the field residue studies) which clearly shows that a sunflower seed dressing with imidacloprid poses no risk to honeybees. This conclusion is confirmed by observations made in more than 10 field studies and several tunnel tests and a French study Experimental study on the toxicity of imidacloprid given in syrup to honey bee (Apis mellifera) colonies http://www3.interscience.wiley.com/cgi-bin/abstract/109630841/ABSTRACT ABSTRACT Two groups of eight honey bee colonies were fed with two different concentrations of imidacloprid in saccharose syrup during summer (each colony was given 1 litre of saccharose syrup containing 0.5 µg litre-1 or 5 µg litre-1 of imidacloprid on 13 occasions). Their development and survival were followed in parallel with control hives (unfed or fed with saccharose syrup) until the end of the following winter. The parameters followed were: adult bee activity (number of bee entering the hive and pollen carrying activity), adult bee population level, capped brood area, frequency of parasitic and other diseases, mortality, number of frames with brood after wintering and a global score of colonies after wintering. The only parameters linked to feeding with imidacloprid-supplemented saccharose syrup when compared with feeding with non-supplemented syrup were: a statistically non-significant higher activity index of adult bees, a significantly higher frequency of pollen carrying during the feeding period and a larger number of capped brood cells. When imidacloprid was no longer applied, activity and pollen carrying were re-established at a similar level for all groups. Repeated feeding with syrup supplemented with imidacloprid did not provoke any immediate or any delayed mortality before, during or following the next winter, whereas such severe effects are described by several French bee keepers as a consequence of imidacloprid use for seed dressing in neighbouring cultures. In any case, during the whole study, mortality was very low in all groups, with no difference between imidacloprid-fed and control colonies. Further research should now address several hypotheses: the troubles described by bee keepers have causes other than imidacloprid; if such troubles are really due to this insecticide, they may only be observed either when bees consume contaminated pollen, when no other sources of food are available, in the presence of synergic factors (that still need to be identified), with some particular races of bees or when colonies are not strong and healthy. 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