Like any good adaptation, there are points where Call me by your name (film) is better than Call me by your name (book); one of these is the handling of visual metaphors, and perhaps more burning should say "expansion". This film can be disassembled and reassembled in hundreds of ways, and I believe that in its "simplicity" is what makes it powerful.
If you've already seen the movie, read the book or seen the buzz in social media, you know about the peach scene (if you don't know, go spoil the movie here), but apart from that there's a lot of peach shots, at first I thought it was just a visual joke, but the more it was repeated the more I thought it was something with more meaning; enter the flies: another quite common catch is flies, again, at first it looks like an accident or something that just happened on location and decided to leave, until it becomes too frequent for it to be something that just happened, but I think both elements, mixed together carry a more powerful message.
One of the main themes of Call me by your name is the concept of maturity as an ideal state that lasts an X amount of time and then begins a process of disintegration that is not necessarily anyone's fault, other than the natural flow of time and how things happen. The peaches are the conduit of this analogy, they will be mature for almost the same time window in which Elio and Oliver can be together, then begin to decompose. The flies are in the film as a kind of memento mori, a constant reminder of mortality, people and relationships, they are circling, waiting for the right moment when everything is going to end and become the emissaries of death. Until the final scene where they are over the face of the character, attacking the corpse of what was.