Updated: May 8, 2019
Imidacloprid is a neurotoxic insecticide often used and overused by professionals and home gardners alike. It's a neonicotinoid pesticide which means - it uses some of the same defense machinery present in nicotine to kill plant-feeding insects. It's effect or contribution to Bee Colony Collapse Disorder, have been repeatedly investigated and identified by numerous scientists all over the word. A consensus has emerged -imidacloprids. when transferred to flowers and pollen contributes to bee colony collapse. Transfer can occur by 1) systemic up-take when dripping the insecticide in the soil while spraying a target plant, 2) when spraying on the target plant prior to or during flowering, 3) via wind-blown droplets to other flowering plants (e.g. the clover in your yard), and 4) when cleaning out a sprayer or other equipment and pouring the residue into the soils. One of the ways it negatively impacts bees is through its neurotoxic activity. It impairs bee ability to keep their colonies cool which is critical during the hottest months. Developing offspring are hurt and adult immune response is compromised.
Bee Colony Collapse Disorder (BCCD) appears to be a perfect (albeit ugly) storm of chemicals and bee pests, resulting in the loss of colonies and the loss of these important pollinators. It's estimated BCCD has resulted in the loss of more than 10 million beehives between 2007 and 2013, estimated to equal billions of dollars ($$$) lost for almond growers, any stone crop, heck - almost all flowering crops. So if you don't particularly care about bees, I know you care about eating. Who doesn't like almonds?
All things are connected, eventually anyway. Think about exposing yourself to extremes of heat and freezing while you are dizzy with the flu and trying to guide your children through a maze of humanity at the airport. You're likely to get lost, infected by some other bug, and possibly misplace your kids till that super, significant other of yours, rescues everyone.
The chemicals remain widely used in the agriculture and horticulture industry because they are so effective at killing insects and arthropods and they are comparatively inexpensive. They continue to be approved in the US because large-scale ag research supports that the chemical, when applied properly