"Multiple possible causes of CCD have been identified. In 2007, some authorities attributed the problem to biotic factors such as Varroa mites and insect diseases (i.e., pathogens[5] including Nosema apis and Israel acute paralysis virus).[6][7] Other proposed causes include environmental change-related stresses,[8] malnutrition, pesticides (e.g.. neonicotinoids such as clothianidin and imidacloprid[9][10][11]), and migratory beekeeping. other possibilities have included both cell phone radiation[12][13] and genetically modified (GM) crops with pest control characteristics although no evidence has been found to suggest this.[14][15]
Emphasis mine.
[14] http://www.sierraclub.org/biotech/whatsnew/whatsnew_2007-03-...
[15] http://www.spiegel.de/international/world/collapsing-colonie...
If someone has a greater understanding than the Wikipedia consensus and the sources to back it, please respond (or update Wikipedia!)