Colony Collapse Disorder is clearly a complex issue. This is the name given to the phenomena where honey bees are abandoning their hives and seemingly disappearing.
Having read various studies and research on this topic and discussed this with some very conscious beekeepers I believe that the most logical explanation is that this is caused from a combination of a few factors that lead to the hive becoming too toxic for the vitality of the colony.
We know that EMF combined with toxins such as pesticides (neonicotinoids are one of the primary aggravators) creates more significant damaging effects on living organisms than either of them on their own. Right now we are living in a time where we have a higher toxic load in our environment from sprayed pesticides and other factors. We also have more microwave radiation than ever before in our environment.
For more information on the combined effects see our recent post on this topic here.
A recent study published in Nature explored the topic of ELF-EMF (low frequency) on Bees and they found that it negatively affected their cognitive and motor abilities.
Here's an expert on how bees are affected by EMF discussing this issue:
Photo By elycefeliz