In the past six years, over 10 million beehives have died mysteriously. This raised concerns about the defecit in crop bee-pollination and an eventual shortage of produce. Bee populations are now so low in the US that it currently takes 60% of the country’s bee colonies just to pollinate one California crop — almonds.

A new study conducted by the University of Maryland and the US Department of Agriculture has pointed to some of the likely causes of the mass death of bees.

Researches observed pollen that was contaminated on average with nine different pesticides and fungicides. Some samples were contaminated with up to 21 foreign chemicals. Scientists identified eight agricultural chemicals associated with increased risk of infection by a parasite called Nosema ceranae.

“There’s growing evidence that fungicides may be affecting the bees on their own and I think what it highlights is a need to reassess how we label these agricultural chemicals,” Dennis van Engelsdorp, the study’s lead author, said in an interview.

Scientists say there’s not one specific pesticide or fungicide to blame, but that the interaction of multiple pesticides is what’s killing bees.

(Photo: Modern Farmer