No matter how diligently and thoroughly a Philadelphia restaurant owner and his staff cleaned their operation, they remained baffled by the persistent and annoying presence of flies.
They would clean every day, and mop the floors, explains Jennifer Brumfield, an entomologist with Parsippany, N.J.-based Western Pest Services. “But no one was cleaning the mop head. The flies were breeding in the mop.”
Despite their tiny size — one eighth of an inch or less