neonic's were first used widespread as seed soaks (2000), so that when the farmers planted the seeds, the birds didn't carry them off. such a use did not affect the bees. however, after a while they started using the neonic's as pesticide sprays (2003 and 2004). this expansion of use of neonic's correpsonds exactly with the beginning of bee colony collapse.
so i think its a real good guess that the neonic's are the culprit here. lets pray we move fast enough to save our bees and our own asses!