I think neonic poisoning is a 'sexy' cause for hive death/CCD. Most people claiming CCD don't regularly monitor varroa mite levels. I think in many cases it is easier to blame a pesticide for the lose of hives than to take the time to monitor and control mites.
Tom[/QUOTE]
I had my hives near treated imidicloprid orange trees for Orange Blossom honey production, I harvested some supers, and extracted some of it and others I stored for winter feed. hives that i gave a super of orange blossom lagged to build up as they went into the honey stores, where other hives build up quickly because they weren't given that Orange Honey super. It didn't kill the colony but they were behind in population compared to my other hives that they weren't ready for Avocado pollination/honey production, it was until then they began to explode in population after they consumed the stored honey (I havent tested the honey, no Lab wanted to do it, would have been Interesting to see). I also had hives near young lemons treated with Imidicloprid they made some honey, but didn't get sick at all, even if I left it there for them. All this was before the trials and suspicions of Imidicloprid on bees, i now avoid keeping bees near such treated fields especially if they bloom heavily and were treated way before bloom. It takes a while for imidicloprid to be taken up by the plant via the roots into the twigs, leaves, flush, bloom, etc........
It appears its the dosage and the crop's physiology of the bloom, Oranges blooms quick and at once, lemons all year round, also the timing of the application of Imidicloprid is a factor as well. They did an experiment in california in regards to Imidicloprid on bee health, (some good data) Lindcove research center. It was Orange blossom, does imidicloprid appear in the nectaries of the plant, yes it does, does it cause harm to a colony(reaches the LD50), yes, but it must reach certain ppb to do so. I will try and find the information online and post it here.
And Varroa.......I lose more bees to varroa than anything else including pesticides, and maybe a rival beek in my area. but pesticides are a lot more easier to blame than other issues such as mites, disease, poor forage which will lead into poor nutrition and succumb much more easier to viruses vecotred by varroa as a result of poor forage.