Scientists investigating the mysterious disappearance of the nation's honey bees are now tracking pesticides and microorganisms as a possible cause.

The disappearing bees have already threatened the livelihood of commercial beekeepers and strained fruit growers. Some beekeepers have even gone as far as refusing to place their hives near chemically treated fields.

Investigators say even though their findings are not definite, they are focusing on the pesticides and microorganisms because of an unnamed pathogen found in dead bees.