I would be interested to know if anyone has data on the movement of the insecticide imidacloprid into nectar and its subsequent effect on bees. Imidacloprid is a new insecticide that is making rapid inroads in alot of crops primarily for control of sap-sucking homoptera (e.g., whiteflies, aphids) and Colorado potato beetle. It is sold under trade names such as Admire, Provado, Marathon, and Merit in the US, with almost all applications as a soil applied treatment for systemic uptake. The reason I am asking is that I have heard a rumor that when applied in greenhouses it is adversely affecting bumblebees. Frankly I am surprised at that rumor since 1) I did not think that much would be trnslocated to the nectar and 2) no other Hymenoptera (primarily sawflies) that I have seen appear to be affected by imidacloprid. (It does have some limit to its range of effectiveness; for example, spider mites and caterpillars are note controlled by it.) Although the rumor pertained to bumblebees, I am asking a honeybee group as the latter are related species that are more closely researched and observed. My interest is related to the fact that imidacloprid soil treatments are increasingly rapidly and supplanting many formerly used foliar spray treatments of various insecticides. Whitney Cranshaw [log in to unmask]