Today I attended an excellent Native Pollinator Workshop put on by Van-Kal Permaculture. We learned about the role native bee species play, a bit about how to identify them and how to attract them.
But I was especially struck by the talk of the impact "neonicotinoid" pesticides have on bee populations. Beyond Pesticides has a nice list of these here: http://www.beyondpesticides.org/pollinators/chemicals.php
We don't often use pesticides around the home or garden, but when we do, we always try food grade Diatomaceous Earth first. D.E. is an organic alternative that is made from fossilized diotoms, a hard-shelled algae that cuts through the exoskeleton of all insects and causes them to dry out.
This powder then becomes de-activated when exposed to water.
D.E. will kill bees the same way that it kills any insect. But it only kills the one bee exposed, and it only kills in a limited area for a limited time. Using D.E. is like using a Scalpel while chemical pesticides are like dropping a bomb. Chemicals can often be blown around, dragged around, and carried back to nests and hives, killing off entire populations.