Scientists investigating a mysterious ailment that killed many of the nation’s honeybees are concentrating on pesticides and a new pathogen as possible culprits, and some beekeepers are already trying to keep their colonies away from pesticide-exposed fields.

After months of study, researchers are finding it difficult to tie the die-off to any single factor.

[Read](http://www.msnbc.msn.com/id/19233858/ “Read the Story”) (AP via MSNBC)