It can kill any bug with an exoskeleton easily, but is safe for any mammal to eat. It is a popular way to kill bugs without using insecticide. Permaculture web site Rich Soil explains how DE works: ...

Older nymphs and adult bed bugs can survive up to a year without food. ... Diatomaceous earth absorbs fats and oils from the bed bugs’ exoskeletons. This causes them to dry out and die.