"The researchers found four common honey bee and bumblebee parasites to be dispersed via flowers: Nosema apis (causes a honey bee disease), Nosema ceranae (causes an emergent disease in honey bees and bumblebees), Crithidia bombi (causes a bumblebee disease) and Apicystis bombi (mostly found in bumblebees). These parasites are known to cause, lethargy, dysentery, colony collapse, and queen death in heavily infected bees. ..."
Read more here: Phys.Org
