Farming's chemicals mix killing more bees - study

Agricultural pesticides sold to farmers ready-mixed into "cocktails" can kill twice as many bees, according to an analysis of 90 studies.

Each measured the impact of environmental stresses such as pesticides and poor nutrition.

Researchers used that data to quantify how combinations of those stresses affected the pollinating insects.

And they say commercial formulas, which contain multiple chemicals, should now require their own licenses.