Multi-pesticide 'cocktails' used on farms can kill twice as many bees as regular pesticides, studies find

"Agricultural pesticides sold to farmers ready-mixed into 'cocktails"' can kill twice as many bees, Victoria Gill reports for BBC News. That's according to an analysis of 90 studies that measured the impact of environmental stressors such as pesticides and poor nutrition. University of Texas at Austin researchers cross-referenced that data to figure out how combinations of those factors affected bees. 

When a pesticide that kills 10 percent of bees is combined with another pesticide that kills 10%, one might expect a cocktail of the two to kill 20% of bees, but a "synergistic effect" could make the combo deadly to 30% to 40% of bees, lead researcher Harry Siviter told Gill.

Such cocktails should be required to have their own license, since pesticides are not generally monitored once they're licensed for use. That would create more of a paper trail when pesticide cocktails harm bees, he said.