The great mystery of bee deaths has been solved. Colony Collapse Disorder is poisoning with a known insect neurotoxin. Clothianidin, a pesticide manufactured by Bayer, has been clearly linked to die offs in Germany and France.
Bayer says that their use is safe for bees, when used according to instructions. This involves using a glue that keeps the pesticides stuck to the seeds on which they're used.
There are many problems with this. Agribusiness corporations are known to evade anything that costs them money. The glue costs money. The equipment and personnel required to apply it costs money. More careful pesticide application to try to keep it from becoming airborne costs money. Obviously, both unscrupulous agribusiness farmers and unknowing small farmers -- not to mention home gardeners -- will, at least occasionally, not use the glue.