Am I missing something here? How can you show a cause and effect relationship with something that is undetectable? Particularly if detectable levels have not shown the suggested effect.

Lora A. Morandin wrote in her PhD thesis (WILD BEES AND AGROECOSYSTEMS)

> Are current agricultural practices harming pollinator populations? Can agricultural methods be modified in ways that promote pollinators and foodproduction? In this thesis I examine the interaction between modern agriculture and wild bees 

> Analysis of imidacloprid residue levels in nectar and pollen of plants grown from treated seeds, or plants grown in fields after soil treatments, have shown low, and, in most cases, *undetectable* levels of imidacloprid.  Field residue levels of imidacloprid in nectar and pollen have not demonstrated harm to honey bees. Results suggest that genetically modified crops and imidacloprid seed treatments, expressing field levels of the proteins and pesticide as tested, will not harm wild bumble bee colonies.

> I did find a negative effect of the nicotinoid insecticide imidacloprid on bumble bee foraging ability when bees were fed elevated doses. However, exposure at realistic levels of imidacloprid encountered in the field did not harm bees. Our finding of negative impact at higher doses emphasizes the importance of following use recommendations in order to prevent negative ecosystem impacts.  I have shown that some new agricultural products and practices negatively impact wild bee populations and crop production while others are not harmful.

Pete

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