What is it called when you are scared of flies?

The fear of flies is called musophobia. It is a specific phobia, which is an anxiety disorder characterized by an intense, irrational fear of a specific object or situation. Musophobia can cause significant distress and impairment in a person's life, and may lead to avoidance behaviors such as avoiding places where flies are likely to be present. In some cases, musophobia may also be associated with other anxiety disorders, such as generalized anxiety disorder or social anxiety disorder.