Where do flies go at night time?

Flies normally fly during the day, which is why they have very good eye sight. They roost in nooks and crannies and so on ready to get a meal from you. The carrot fly, which is a pest of carrots, actually roosts in hedgerows and we devised a means of passing a disease to them in the hedgerow. Unfortunately, unlike the mosquito repellents, that's a very long way from commercial development.